{"msg":"操作系统","code":200,"data":{"currentIndex":null,"examId":null,"examTime":null,"questionList":[{"id":"794930397027782657","title":"<p>某计算机系统中的进程管理采用三态模型，那么下图所示的PCB（进程控制块）的组织方式采用（ ），图中（请作答此空）。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/2da8c5acb9ed773777a2924d11001e2d.jpg?x-oss-process=style/ruankaodaren\" title=\"2da8c5acb9ed773777a2924d11001e2d.jpg\" alt=\"1.jpg\"/></p><br/>","analyze":"<p>进程控制块PCB的组织方式如下。</p><p>（1） 线性表方式：不论进程的状态如何，将所有的PCB连续地存放在内存的系统区，这种方式适用于系统中进程数目不多的情况。</p><p>（2） 索引表方式：该方式是线性表方式的改进，系统按照进程的状态分别建立就绪索引表、阻塞索引表等。</p><p>（3） 链接表方式：系统按照进程的状态将进程的PCB组成队列，从而形成就绪队列、阻塞队列、运行队列等。</p><p>运行进程为PCB1、PCB3；就绪进程为PCB2、PCB4、PCB5；阻塞进程为PCB6、PCB7、PCB8、PCB9。</p>","multi":0,"questionType":1,"answer":"C","chooseItem":["794930398999105537"],"itemList":[{"id":"794930398969745409","questionId":"794930397027782657","content":"有1个运行进程，2个就绪进程，4个阻塞进程","answer":0,"chooseValue":"A"},{"id":"794930398982328321","questionId":"794930397027782657","content":"有2个运行进程，3个就绪进程，3个阻塞进程","answer":0,"chooseValue":"B"},{"id":"794930398999105537","questionId":"794930397027782657","content":"有2个运行进程，3个就绪进程，4个阻塞进程","answer":1,"chooseValue":"C"},{"id":"794930399011688449","questionId":"794930397027782657","content":"有3个运行进程，2个就绪进程，4个阻塞进程","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930556310671361","title":"<p>雷达设计人员在设计数字信号处理单元时，其处理器普遍采用DSP芯片（比如TI公司的TMS320C63xx），通常DSP芯片采用哈佛 （Harvard）体系结构，以下关于哈佛体系结构特征的描述，不正确是 （8） 。</p>","analyze":"<p>哈佛体系结构特点是程序存储器与数据存储器分开，每个存储器独立编址、独立访问，有着不同的数据宽度。哈佛体系结构允许在一个机器周期内同时获得指令字和操作数，从而提高了执行速度和数据的吞吐率。</p><p>哈佛体系结构的数据存储区与代码存储区是物理分离的，不可能因数据缓冲区溢出而覆盖执行的代码，从而执行到非法构造的代码。</p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930558185525249"],"itemList":[{"id":"794930558164553729","questionId":"794930556310671361","content":"程序和数据具有独立的存储空间，允许同时取指令和取操作数，并允许在程序空间或数据空间之间互传数据","answer":0,"chooseValue":"A"},{"id":"794930558185525249","questionId":"794930556310671361","content":"处理器内用多总线结构，保证了在一个机器周期内可以多次访问程序空间和数据空间","answer":1,"chooseValue":"B"},{"id":"794930558206496769","questionId":"794930556310671361","content":"哈佛体系结构可以被缓冲区溢出攻击而执行非法代码","answer":0,"chooseValue":"C"},{"id":"794930558223273985","questionId":"794930556310671361","content":"处理器内部采用多处理单元，可以在一个指令周期内同时进行运算","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930320808890369","title":"<p><br/></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">进程</span>P1、P2、P3、P4、P5和P6的前趋图如下所示：</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/d4dda4b0df7fbcce161029ec42cad10d.png?x-oss-process=style/ruankaodaren\"/></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">若用</span><span style=\"font-size: 10.5pt;\">PV操作控制这6个进程的同步与互斥的程序如下，空③和空④处应分别为（49）。</span><br/></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-size: 10.5pt;\"><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/00a24d644e50a859e3c36df27a2e63dd.png?x-oss-process=style/ruankaodaren\"/></span></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p>","analyze":"<p><br/></p><p class=\"MsoNormal\" style=\"text-indent: 21pt; line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\">(49)根据前驱图，P3进程运行结束需要利用两个V操作分别通知P4、P5进程，故空③应为两个V操作；又由于P4执行前需要等待进程P2、P3的结果，需要2个P操作，而P4进程的程序中执行前只有1个P操作，故空④应为1个P操作。采用排除法，对于试题(49)的选项A、选项B、选项C和选项D中，只有选项A满足条件。</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p>","multi":0,"questionType":1,"answer":"A","chooseItem":["794930322713104385"],"itemList":[{"id":"794930322713104385","questionId":"794930320808890369","content":"V(S4)V(S5)和P(S3)","answer":1,"chooseValue":"A"},{"id":"794930322738270209","questionId":"794930320808890369","content":"P(S4)P(S5)和V(S3)","answer":0,"chooseValue":"B"},{"id":"794930322763436033","questionId":"794930320808890369","content":"V(S3)V(S4)和V(S5)","answer":0,"chooseValue":"C"},{"id":"794930322784407553","questionId":"794930320808890369","content":"P(S3)V(S4)和P(S3)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930501365288961","title":"<p><br/></p><p>某计算机系统页面大小为4K，进程P1 的页面变换表如下图示，看P1要访问数据的逻辑地址为十六进制1B1AH，那么该逻辑地址经过变换后，其对应的物理地址应为十六进制。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/95146837012f0fca5492efc585506717.jpg?x-oss-process=style/ruankaodaren\" title=\"95146837012f0fca5492efc585506717.jpg\" alt=\"1.jpg\"/></p><br/>","analyze":"<p>页面大小4K=2^12，页内地址有12位。对应十六进行逻辑地址的B1A，逻辑地址中的1就是页号，通过查表可知对应的物理块号是6，物理地址为6B1AH。</p>","multi":0,"questionType":1,"answer":"C","chooseItem":["794930503248531457"],"itemList":[{"id":"794930503214977025","questionId":"794930501365288961","content":"1B1AH","answer":0,"chooseValue":"A"},{"id":"794930503231754241","questionId":"794930501365288961","content":"3B1AH","answer":0,"chooseValue":"B"},{"id":"794930503248531457","questionId":"794930501365288961","content":"6B1AH","answer":1,"chooseValue":"C"},{"id":"794930503265308673","questionId":"794930501365288961","content":"8B1AH","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930475746480129","title":"假设系统有n（n≥5）个进程共享资源R，且资源R的可用数为5。若采用PV 操作，则相应的信号量S的取值范围应为（7）。","analyze":"当n个进程都需要申请资源R时，只有5个进程占用了资源R，所以有n-5个进程需要等待，这时候信号量S是-（n-5），而当所有进程都不需要申请资源R时，信号量S是5。","multi":0,"questionType":1,"answer":"D","chooseItem":["794930477742968833"],"itemList":[{"id":"794930477642305537","questionId":"794930475746480129","content":"-1～n-1","answer":0,"chooseValue":"A"},{"id":"794930477680054273","questionId":"794930475746480129","content":"-5～5","answer":0,"chooseValue":"B"},{"id":"794930477713608705","questionId":"794930475746480129","content":"-(n-1)～1","answer":0,"chooseValue":"C"},{"id":"794930477742968833","questionId":"794930475746480129","content":"-(n-5)～5","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930402782367745","title":"主存与Cache的地址映射方式中，（ ）方式可以实现主存任意一块装入 Cache 中任意位置，只有装满才需要替换。","analyze":"<p>全相联地址映射：主存的任意一块可以映像到 Cache 中的任意一块。</p><p>直接相联映射：主存中一块只能映像到 Cache 的一个特定的块中。</p><p>组相联的映射：各区中的某一块只能存入缓存的同组号的空间内，但组内各块地址之间则可以任意存放。即从主存的组到Cache的组之间采用直接映像方式，在两个对应的组内部采用全相联映像方式。</p>","multi":0,"questionType":1,"answer":"A","chooseItem":["794930404665610241"],"itemList":[{"id":"794930404665610241","questionId":"794930402782367745","content":"全相联","answer":1,"chooseValue":"A"},{"id":"794930404686581761","questionId":"794930402782367745","content":"直接映射","answer":0,"chooseValue":"B"},{"id":"794930404703358977","questionId":"794930402782367745","content":"组相联","answer":0,"chooseValue":"C"},{"id":"794930404728524801","questionId":"794930402782367745","content":"串并联","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930467223654401","title":"<p> </p><p>假设计算机系统的页面大小为4K，进程P的页面变换表如下表所示。若P要访问的逻辑地址为十六进制3C20H，那么该逻辑地址经过地址变换后，其物理地址应为（4）。</p><p><img style=\"max-width:100%;height:auto\" title=\"5f4f0039361830ea0809b0b0053a95f2.jpg\" alt=\"1.jpg\" src=\"https://image.chaiding.com/ruankao/5f4f0039361830ea0809b0b0053a95f2.jpg?x-oss-process=style/ruankaodaren\"/></p><br/>","analyze":"<p>4K=2^12，使用十六进制表示为1000H，所以逻辑地址转换成物理地址时，后面3位不用改变，只需要改变最左边一位。对于逻辑地址3C20H，页号3对应的物理块号是6，所以物理地址为6C20H。</p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930469127868417"],"itemList":[{"id":"794930469077536769","questionId":"794930467223654401","content":"2048H","answer":0,"chooseValue":"A"},{"id":"794930469094313985","questionId":"794930467223654401","content":"3C20H","answer":0,"chooseValue":"B"},{"id":"794930469111091201","questionId":"794930467223654401","content":"5C20H","answer":0,"chooseValue":"C"},{"id":"794930469127868417","questionId":"794930467223654401","content":"6C20H","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930416170586113","title":"<p>某文件系统采用链式存储管理方案，磁盘块的大小为1024字节。文件Myfile.doc由5个逻辑记录组成，每个逻辑记录的大小与磁盘块的大小相等，并依次存放在121、75、86、65和114号磁盘块上。若需要存取文件的第5120逻辑字节处的信息，应该访问（）号磁盘块。</p>","analyze":"<p>每个逻辑记录的大小与磁盘块的大小相等(1024字节)，而需要存取文件的第5120逻辑字节处的信息，由计算得5120=1024*5，即该处信息在第5个逻辑记录最后一个字节上（注意区分“第5120字节”和“index 5120的字节”，后者是指第5121个），对应的是114号磁盘块。</p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930418129326081"],"itemList":[{"id":"794930418032857089","questionId":"794930416170586113","content":"7","answer":0,"chooseValue":"A"},{"id":"794930418062217217","questionId":"794930416170586113","content":"85","answer":0,"chooseValue":"B"},{"id":"794930418099965953","questionId":"794930416170586113","content":"65","answer":0,"chooseValue":"C"},{"id":"794930418129326081","questionId":"794930416170586113","content":"114","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930360755441665","title":"<p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/87fffca4aad19889956239fc2930de1d.png?x-oss-process=style/ruankaodaren\"/></p>","analyze":"<p><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">本题考查操作系统中</span>PV<span style=\"font-family:宋体\">操作知识点。信号量是一个整型变量，根据控制对象的不同赋不同的值。信号量可分为两类。公用信号量：实现进程间的互斥，初值为资源的数目。私用信号量：实现进程间的同步，初值</span></span><span style=\"font-family: Calibri; font-size: 10.5pt;\">=0</span><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">或某个整数。</span></span><br/></p>","multi":0,"questionType":1,"answer":"A","chooseItem":["794930362596741121"],"itemList":[{"id":"794930362596741121","questionId":"794930360755441665","content":"V(S1)、P(S1)和V(S2)V(S3)","answer":1,"chooseValue":"A"},{"id":"794930362613518337","questionId":"794930360755441665","content":"P(S1)、V(S1)和V(S2)V(S3)","answer":0,"chooseValue":"B"},{"id":"794930362630295553","questionId":"794930360755441665","content":"V(S1)、V(S2)和P(S1)V(S3)","answer":0,"chooseValue":"C"},{"id":"794930362647072769","questionId":"794930360755441665","content":"P(S1)、V(S2)和V(S1)V(S3)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930343609126913","title":"<p><span style=\"text-indent: 20.7pt; font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">计算机运行过程中，</span>CPU <span style=\"font-family:宋体\">需要与外设进行数据交换。采用（ </span></span><span style=\"text-indent: 20.7pt; font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">）控制技术时，</span> CPU <span style=\"font-family:宋体\">与外设可并行工作。</span></span></p><p class=\"MsoNormal\" style=\"text-indent: 20.7pt;\"><br/></p>","analyze":"<p><br/></p><p class=\"MsoNormal\" style=\"text-indent: 20.7pt;\"><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">程序查询方式的原理是：当主机进行</span>I/O<span style=\"font-family:宋体\">操作时，首先发出询问信号，读取设备的状态并根据设备状态决定下一步操作究竟是进行数据传输还是等待。这种控制下，</span><span style=\"font-family:Calibri\">CPU</span><span style=\"font-family:宋体\">一旦启动</span><span style=\"font-family:Calibri\">I/O</span><span style=\"font-family:宋体\">，必须停止现行程序的运行，并在现行程序中插入一段程序。程序查询方式的主要特点是</span><span style=\"font-family:Calibri\">CPU</span><span style=\"font-family:宋体\">有踏步等待现象，</span><span style=\"font-family:Calibri\">CPU</span><span style=\"font-family:宋体\">与</span><span style=\"font-family:Calibri\">I/O</span><span style=\"font-family:宋体\">串行工作。</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"text-indent: 20.7pt;\"><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">程序中断是指计算机执行现行程序的过程中，出现某些急需处理的异常情况和特殊请求，</span>cpu<span style=\"font-family:宋体\">暂时终止现行程序，而转去对随机发生的更紧迫的事件进行处理，在处理完毕后，</span><span style=\"font-family:Calibri\">cpu</span><span style=\"font-family:宋体\">将自动返回原来的程序继续执行。在中断方式中</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\">CPU <span style=\"font-family:宋体\">与外设可并行工作</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">。</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"text-indent: 20.7pt;\"><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">直接内存存取</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\">DMA<span style=\"font-family:宋体\">是指在内存与</span><span style=\"font-family:Calibri\">I/O</span><span style=\"font-family:宋体\">设备间传送数据块的过程中，不需要</span><span style=\"font-family:Calibri\">CPU</span><span style=\"font-family:宋体\">的任何干涉，只需要</span><span style=\"font-family:Calibri\">CPU</span><span style=\"font-family:宋体\">在过程考试启动与过程结束时的处理，实际操作由</span><span style=\"font-family:Calibri\">DMA</span><span style=\"font-family:宋体\">硬件直接执行完成，</span><span style=\"font-family:Calibri\">CPU</span><span style=\"font-family:宋体\">在此传送过程中可做别的事情。在</span><span style=\"font-family:Calibri\">DMA</span><span style=\"font-family:宋体\">方式中</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\">CPU <span style=\"font-family:宋体\">与外设可并行工作</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">。</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"text-indent: 20.7pt;\"><span style=\"font-family: 黑体; font-size: 10.5pt; background: #7F7F7F;\"><span style=\"font-family:黑体\">参考答案</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">：</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\">B</span></p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930345500758017"],"itemList":[{"id":"794930345479786497","questionId":"794930343609126913","content":"程序查询方式和中断方式","answer":0,"chooseValue":"A"},{"id":"794930345500758017","questionId":"794930343609126913","content":"中断方式和DMA方式","answer":1,"chooseValue":"B"},{"id":"794930345521729537","questionId":"794930343609126913","content":"程序查询方式和DMA方式","answer":0,"chooseValue":"C"},{"id":"794930345542701057","questionId":"794930343609126913","content":"程序查询方式、中断方式和DMA方式","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930430263447553","title":"采用微内核结构的操作系统提高了系统的灵活性和可扩展性，（）。","analyze":"<p>在设计微内核OS时，采用了面向对象的技术，其中的“封装”，“继承”，“对象类”和“多态性”，以及在对象之间采用消息传递机制等，都十分有利于提高系统的“正确性”、“可靠性”、“易修改性”、“易扩展性”等，而且还能显著地减少开发系统所付出的开销。采用微内核结构的操作系统与传统的操作系统相比，其优点是提高了系统的灵活性、可扩充性，增强了系统的可靠性，提供了对分布式系统的支持。其原因如下。</p><p>①灵活性和可扩展性：由于微内核OS的许多功能是由相对独立的服务器软件来实现的，当开发了新的硬件和软件时，微内核OS只需在相应的服务器中增加新的功能，或再增加一个专门的服务器。与此同时，也必然改善系统的灵活性，不仅可在操作系统中增加新的功能，还可修改原有功能，以及删除已过时的功能，以形成一个更为精干有效的操作系统。</p><p>②增强了系统的可靠性和可移植性：由于微内核是出于精心设计和严格测试的，容易保证其正确性；另一方面是它提供了规范而精简的应用程序接口(API)，为微内核外部的程序编制高质量的代码创造了条件。此外，由于所有服务器都是运行在用户态，服务器与服务器之间采用的是消息传递通信机制，因此，当某个服务器出现错误时，不会影响内核，也不会影响其他服务器。另外，由于在微内核结构的操作系统中，所有与特定CPU和I/O设备硬件有关的代码，均放在内核和内核下面的硬件隐藏层中，而操作系统其他绝大部分(即各种服务器)均与硬件平台无关，因而，把操作系统移植到另一个计算机硬件平台上所需作的修改是比较小的。</p><p>③提供了对分布式系统的支持：由于在微内核OS中，客户和服务器之间以及服务器和服务器之间的通信，是采用消息传递通信机制进行的，致使微内核OS能很好地支持分布式系统和网络系统。事实上，只要在分布式系统中赋予所有进程和服务器唯一的标识符，在微内核中再配置一张系统映射表(即进程和服务器的标识符与它们所驻留的机器之间的对应表)，在进行客户与服务器通信时，只需在所发送的消息中标上发送进程和接收进程的标识符，微内核便可利用系统映射表将消息发往目标，而无论目标是驻留在哪台机器上。</p>","multi":0,"questionType":1,"answer":"A","chooseItem":["794930432129912833"],"itemList":[{"id":"794930432129912833","questionId":"794930430263447553","content":"并增强了系统的可靠性和可移植性，可运行于分布式系统中","answer":1,"chooseValue":"A"},{"id":"794930432142495745","questionId":"794930430263447553","content":"并增强了系统的可靠性和可移植性，但不适用于分布式系统","answer":0,"chooseValue":"B"},{"id":"794930432163467265","questionId":"794930430263447553","content":"但降低了系统的可靠性和可移植性，可运行于分布式系统中","answer":0,"chooseValue":"C"},{"id":"794930432180244481","questionId":"794930430263447553","content":"但降低了系统的可靠性和可移植性，不适用于分布式系统","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930375099961345","title":"<p>I/O设备管理一般分为4个层次，如下图所示。图中①②③分别对应（ ）<br/></p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/12d9402de098fc602a016a1d561417cf.png?x-oss-process=style/ruankaodaren\"/></p>","analyze":"<p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/a2d7e6bc5660627e8132b469a3990024.png?x-oss-process=style/ruankaodaren\"/></p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930377016758273"],"itemList":[{"id":"794930376953843713","questionId":"794930375099961345","content":"设备驱动程序、虚设备管理、与设备无关的系统软件","answer":0,"chooseValue":"A"},{"id":"794930376974815233","questionId":"794930375099961345","content":"设备驱动程序、与设备无关的系统软件、虚设备管理","answer":0,"chooseValue":"B"},{"id":"794930376995786753","questionId":"794930375099961345","content":"中断处理程序、与设备无关的系统软件、设备驱动程序","answer":0,"chooseValue":"C"},{"id":"794930377016758273","questionId":"794930375099961345","content":"中断处理程序、设备驱动程序、与设备无关的系统软件","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930340773777409","title":"<p><br/></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 0pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">进程</span>P1、P2、P3、P4、P5和P6的前趋图如下所示：</span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 0pt; line-height: 150%;\"><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/9081f24be2baec8826b8b1adb4033aca.png?x-oss-process=style/ruankaodaren\"/></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 0pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">若用</span>PV操作控制这6个进程的同步与互斥的程序如下，</span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">空</span>f和空g处应分别为（48）。</span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 0pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/228c2591276d8d525a097b865096df58.png?x-oss-process=style/ruankaodaren\"/></span></p>","analyze":"<p><br/></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 0pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">对于试题（</span>48)，根据前驱图P5进程开始运行前必须等待P3进程的通知，需要用P (S5)操作测试P3进程是否运行完，故空f应填写P (S5)：P5进程运行结束需要利用V操作通知P6进程，故空g应填写V(S7)。</span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\"><span style=\"font-family: 宋体; font-size: 10.5pt; background: #7F7F7F;\"><span style=\"font-family:宋体\">参考答案</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">：</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\">（48）C</span></p>","multi":0,"questionType":1,"answer":"C","chooseItem":["794930342652825601"],"itemList":[{"id":"794930342623465473","questionId":"794930340773777409","content":"V(S5)和V(S7)","answer":0,"chooseValue":"A"},{"id":"794930342636048385","questionId":"794930340773777409","content":"P(S5)和P(S7)","answer":0,"chooseValue":"B"},{"id":"794930342652825601","questionId":"794930340773777409","content":"P(S5)和V(S7)","answer":1,"chooseValue":"C"},{"id":"794930342665408513","questionId":"794930340773777409","content":"V(S5)和P(S7)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930495610703873","title":"<p>某系统中有3 个并发进程竞争资源R，每个进程都需要4个R，那么至少有( )个R，才能保证系统不会发生死锁。</p>","analyze":"<p>每个进程需要4个R才能执行，则当每个进程都只有3个R时是死锁最坏的情况，即3*3=9个资源是死锁发生的最大资源数，再加1就能保证不发生死锁，因此是10.</p>","multi":0,"questionType":1,"answer":"A","chooseItem":["794930497481363457"],"itemList":[{"id":"794930497481363457","questionId":"794930495610703873","content":"10","answer":1,"chooseValue":"A"},{"id":"794930497519112193","questionId":"794930495610703873","content":"11","answer":0,"chooseValue":"B"},{"id":"794930497556860929","questionId":"794930495610703873","content":"12","answer":0,"chooseValue":"C"},{"id":"794930497586221057","questionId":"794930495610703873","content":"13","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930478653132801","title":"（10）不是操作系统关心的主要问题。","analyze":"操作系统可以管理计算机的软、硬件资源以及为用户与计算机之间提供接口。选项D是由专门的程序去完成的。","multi":0,"questionType":1,"answer":"D","chooseItem":["794930480532180993"],"itemList":[{"id":"794930480490237953","questionId":"794930478653132801","content":"管理计算机裸机","answer":0,"chooseValue":"A"},{"id":"794930480507015169","questionId":"794930478653132801","content":"设计、提供用户程序与计算机硬件系统的界面","answer":0,"chooseValue":"B"},{"id":"794930480519598081","questionId":"794930478653132801","content":"管理计算机系统资源","answer":0,"chooseValue":"C"},{"id":"794930480532180993","questionId":"794930478653132801","content":"高级程序设计语言的编译器","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930405672243201","title":"设指令由取指、分析、执行3个子部件完成，并且每个子部件的时间均为Δt。若采用常规标量单流水线处理机（即该处理机的度为1），连续执行12条指令，共需 （请作答此空） Δt。若采用度为4的超标量流水线处理机，连续执行上述12条指令，只需 （ ） Δt。","analyze":"<p>指令由取指、分析和执行3个子部件完成，n=3，且每个子部件的时间均为Δt。若采用常规标量单流水线处理机（即该处理机的度m=1），连续执行12条（k=12）指令的时空图如图所示。执行这12条指令所需的总时间为：Tk=（k+3-1）*Δt=（12+3）*Δt=14Δt。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/19db08393f77bd0c162d2919e816db0a.jpg?x-oss-process=style/ruankaodaren\" title=\"19db08393f77bd0c162d2919e816db0a.jpg\" alt=\"1.jpg\"/></p><p>若采用度为4（m=4）的超标量流水线处理机，连续执行上述12条（k=12）指令的时空图如图所</p><p>示。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/12f70a9a3e5e0f900a1dd540245ed7f1.jpg?x-oss-process=style/ruankaodaren\" title=\"12f70a9a3e5e0f900a1dd540245ed7f1.jpg\" alt=\"2.jpg\"/>由图可知，执行这12条指令所需的总时间只需要5Δt。</p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930407547097089"],"itemList":[{"id":"794930407526125569","questionId":"794930405672243201","content":"12","answer":0,"chooseValue":"A"},{"id":"794930407547097089","questionId":"794930405672243201","content":"14","answer":1,"chooseValue":"B"},{"id":"794930407563874305","questionId":"794930405672243201","content":"16","answer":0,"chooseValue":"C"},{"id":"794930407580651521","questionId":"794930405672243201","content":"18","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930444410834945","title":"某文件系统采用链式存储管理方案，磁盘块的大小为1024字节。文件Myfile.doc由5个逻辑记录组成，每个逻辑记录的大小与磁盘块的大小相等，并依次存放在121、75、86、65和114号磁盘块上。若需要存取文件的第5120逻辑字节处的信息，应该访问 （ ） 号磁盘块。","analyze":"每个逻辑记录的大小与磁盘块的大小相等(1024字节)，而需要存取文件的第5120逻辑字节处的信息，由计算得5120=1024*5，即该处信息在第5个逻辑记录上，对应的是114号磁盘块。","multi":0,"questionType":1,"answer":"D","chooseItem":["794930446310854657"],"itemList":[{"id":"794930446252134401","questionId":"794930444410834945","content":"7","answer":0,"chooseValue":"A"},{"id":"794930446268911617","questionId":"794930444410834945","content":"85","answer":0,"chooseValue":"B"},{"id":"794930446289883137","questionId":"794930444410834945","content":"65","answer":0,"chooseValue":"C"},{"id":"794930446310854657","questionId":"794930444410834945","content":"114","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930346482225153","title":"<p><br/></p><p class=\"MsoNormal\"><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">更适合用来开发操作系统的编程语言是（ </span></span><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"> <span style=\"font-family:宋体\">）。</span></span></p>","analyze":"<p><br/></p><p class=\"MsoNormal\"><span style=\"font-family: 宋体; font-size: 10.5pt;\">C<span style=\"font-family:宋体\">语言是处于汇编语言和高级语言之间的一种中间型程序设计语言，常被称为中级语言。它既有高级语言的基本特点，又具有汇编语言面向硬件和系统，可以直接访问硬件的功能。</span><span style=\"font-family:Calibri\">C</span><span style=\"font-family:宋体\">语言适用于</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">开发操作系统</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">。</span>C++<span style=\"font-family:宋体\">是</span><span style=\"font-family:Calibri\">C</span><span style=\"font-family:宋体\">语言的继承，它既可以进行</span><span style=\"font-family:Calibri\">C</span><span style=\"font-family:宋体\">语言的过程化程序设计，又可以进行以抽象数据类型为特点的基于对象的程序设计，还可以进行以继承和多态为特点的面向对象的程序设计。</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"text-indent: 20.7pt;\"><span style=\"font-family: 黑体; font-size: 10.5pt; background: #7F7F7F;\"><span style=\"font-family:黑体\">参考答案</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">：</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\">A</span></p>","multi":0,"questionType":1,"answer":"A","chooseItem":["794930348453548033"],"itemList":[{"id":"794930348453548033","questionId":"794930346482225153","content":"C/C++","answer":1,"chooseValue":"A"},{"id":"794930348487102465","questionId":"794930346482225153","content":"Java","answer":0,"chooseValue":"B"},{"id":"794930348516462593","questionId":"794930346482225153","content":"Python","answer":0,"chooseValue":"C"},{"id":"794930348541628417","questionId":"794930346482225153","content":"JavaScript","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930492779548673","title":"<p>某文件管理系统在磁盘上建立了位示图(bitmap) ，记录磁盘的使用情况。若计算机系统的字长为32 位，磁盘的容量为300GB ，物理块的大小为4MB ，那么位示图的大小需要()个字。</p>","analyze":"<p>共有300GB/4MB=75K个物理块，在位示图中，每个物理块占1位，即位示图大小为75*1024=76800bit（注意大写的GB、MB以1024为计量），也就是76800/32=2400个字.</p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930494654402561"],"itemList":[{"id":"794930494629236737","questionId":"794930492779548673","content":"1200","answer":0,"chooseValue":"A"},{"id":"794930494654402561","questionId":"794930492779548673","content":"2400","answer":1,"chooseValue":"B"},{"id":"794930494671179777","questionId":"794930492779548673","content":"6400","answer":0,"chooseValue":"C"},{"id":"794930494700539905","questionId":"794930492779548673","content":"9600","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930411309387777","title":"精简指令系统RISC的特点不包括（ ）","analyze":"CISC系统中的指令可以对主存单元中的数据直接进行处理。典型的 CISC 通常都有指令能够直接对主存单元中的数据进行处理，其执行速度较慢。","multi":0,"questionType":1,"answer":"C","chooseItem":["794930413276516353"],"itemList":[{"id":"794930413247156225","questionId":"794930411309387777","content":"指令数量少。优先选取使用频率最高的一些简单指令和一些常用指令，避免使用复杂指令。","answer":0,"chooseValue":"A"},{"id":"794930413259739137","questionId":"794930411309387777","content":"指令的寻址方式少。通常只支持寄存器寻址方式、立即数寻址方式和相对寻址方式。","answer":0,"chooseValue":"B"},{"id":"794930413276516353","questionId":"794930411309387777","content":"指令可以对主存单元中的数据直接进行处理。典型的 RISC 通常都有指令能够直接对主存单元中的数据进行处理，其执行速度较快。","answer":1,"chooseValue":"C"},{"id":"794930413293293569","questionId":"794930411309387777","content":"以硬布线逻辑控制为主。为了提高操作的执行速度，通常采用硬布线逻辑（组合逻辑）来构建控制器。","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930441592262657","title":"页式存储系统的逻辑地址是由页号和页内地址两部分组成。假定页面的大小为4K，地址变换过程如下图所示，图中逻辑地址用十进制表示。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/d504fad7c1332fa71e5b1c7b37b8748e.jpg?x-oss-process=style/ruankaodaren\" title=\"d504fad7c1332fa71e5b1c7b37b8748e.jpg\" alt=\"1.jpg\"/><br/>图中有效地址经过变换后，十进制物理地址a应为（）。","analyze":"本题考查的是页式存储管理中的地址变换知识。在页式存储管理中，有效地址除页的大小，取整为页号，取余为页内地址。本题页面的大小为4K，有效地址8644除4096，取整为2，取余为452。我们先查页表得物理块号8，因此a的有效地址为8×4096+452= 33220。","multi":0,"questionType":1,"answer":"A","chooseItem":["794930443441950721"],"itemList":[{"id":"794930443441950721","questionId":"794930441592262657","content":"33220","answer":1,"chooseValue":"A"},{"id":"794930443458727937","questionId":"794930441592262657","content":"8644","answer":0,"chooseValue":"B"},{"id":"794930443475505153","questionId":"794930441592262657","content":"4548","answer":0,"chooseValue":"C"},{"id":"794930443492282369","questionId":"794930441592262657","content":"2500","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930433086214145","title":"系统中有R类资源m个，现有n个进程互斥使用。若每个进程对R资源的最大需求为w，那么当m、n、w取下表中的数值时，对于表中的a～e共5种方案，（）可能会发生死锁。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/5235744ba05ad8bb5759a5e88d2b5bd9.jpg?x-oss-process=style/ruankaodaren\" title=\"5235744ba05ad8bb5759a5e88d2b5bd9.jpg\" alt=\"1.jpg\"/>","analyze":"<p>系统中同类资源分配不当将引起死锁。通常情况下，若系统中有m个单位的存储器资源，它被n个进程使用，而每个进程都要求w个单位的存储器资源，则当[n×(w-1)+1]＞m时，系统可能会引起死锁。</p><p>对于情况a：m=2、n=1、w=2，即系统中有两个资源，一个进程使用，该进程最多要求两个资源。由于n×(w-1)+1=1×(2-1)+1=2=m，因此系统不会发生死锁。</p><p>对于情况b：m=2、n=2、w=1，即系统中有两个资源，两个进程使用，每个进程最多要求一个资源。因为n×(w-1)+1=2×(1-1)+1=1＜m=2，所以系统不会发生死锁。</p><p>对于情况c：m=2、n=2、w=2，即系统中有两个资源，两个进程使用，每个进程最多要求两个资源。n×(w-1)+1-2×(2-1)+1=3＞m=2，系统可能会引起死锁。理由是：采用轮流地为每个进程分配存储器资源的分配策略，则第1轮系统先为每个进程分配1个资源；第2轮系统中已无可供分配的资源，使各个进程都处于等待状态，将导致系统发生死锁。</p><p>对于情况d：m=4、n=3、w=2，即系统中有4个资源，3个进程使用，每个进程最多要求两个资源。n×(w-1)+1-3×(2-1)+1=4=m，系统不会发生死锁。理由是：采用轮流地为每个进程分配存储器资源的分配策略，则第1轮系统先为每个进程分配1个存储器资源。系统中还剩1个资源，可以使其中的某个进程得到所需资源而运行完毕。当该进程释放所占用的2个资源后，可以使其他进程得到所需的存储器资源而运行完毕，所以系统不会发生死锁。</p><p>对于情况e：m=4、n=3、w=3，即系统中有4个资源，3个进程使用，每个进程最多要求3个资源。n×(w-1)+1=3×(3-1)+1=7＞m=4，系统可能会引起死锁。理由是：采用的分配策略轮流地为每个进程分配，则第1轮系统先为每个进程分配一个存储器资源；第2轮</p><p>系统为某一个进程分配一个资源之后，系统中已无可供分配的存储器资源，使各个进程都处于等待状态而导致系统发生死锁。</p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930434994622465"],"itemList":[{"id":"794930434944290817","questionId":"794930433086214145","content":"a和b","answer":0,"chooseValue":"A"},{"id":"794930434961068033","questionId":"794930433086214145","content":"b和c","answer":0,"chooseValue":"B"},{"id":"794930434977845249","questionId":"794930433086214145","content":"c和d","answer":0,"chooseValue":"C"},{"id":"794930434994622465","questionId":"794930433086214145","content":"c和e","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930335073718273","title":"<p><br/></p><p class=\"MsoNormal\"><span style=\"mso-spacerun:'yes';font-family:宋体;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">进程</span>P1、P2、P3、P4、P5和P6的前趋图如下所示：</span></p><p class=\"MsoNormal\"><span style=\"mso-spacerun:'yes';font-family:宋体;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/795b534ce4df864de2817aa4cda8d05d.png?x-oss-process=style/ruankaodaren\"/></span></p><p class=\"MsoNormal\"><span style=\"font-family:宋体\">若用</span><span style=\"font-family: 宋体; font-size: 10.5pt;\">PV操作控制这6个进程的同步与互斥的程序如下，那么程序中的空a、空b和空c处应分别为（46）。</span><span style=\"mso-spacerun:'yes';font-family:宋体;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><br/></span></p><p class=\"MsoNormal\"><span style=\"font-family: 宋体; font-size: 10.5pt;\"><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/31f1bd99bf1c5116df96c768b7fece16.png?x-oss-process=style/ruankaodaren\"/></span></p>","analyze":"<p><br/></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 0pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">对于试题（</span>46)，根据前驱图P2进程需要等待P1进程的通知，故需要利用P (S1) 操作测试P1进程是否运行完，P2进程运行结束需要利用V操作分别通知P4进程，所以空a应填V (S2)用以通知P4进程可以执行：前驱图P3进程开始运行前必须等待P1 进程的通知，需要用P操作测试P1进程是否运行完，所以空b应填P (S2)操作测试P1进程是否运行完；P3进程运行结束需要利用V (S4) V (S5)操作通知P4和P5进程可以开始运行，故空c应填V (S4) V (S5)。</span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 0pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\"><span style=\"font-family: 宋体; font-size: 10.5pt; background: #7F7F7F;\"><span style=\"font-family:宋体\">参考答案</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">：</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">（</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\">46）A</span></p>","multi":0,"questionType":1,"answer":"A","chooseItem":["794930336940183553"],"itemList":[{"id":"794930336940183553","questionId":"794930335073718273","content":"V(S3)、P(S2)和V(S4)V(S5)","answer":1,"chooseValue":"A"},{"id":"794930336961155073","questionId":"794930335073718273","content":"P(S3)、P(S2)和V(S4)V(S5)","answer":0,"chooseValue":"B"},{"id":"794930336982126593","questionId":"794930335073718273","content":"V(S2)、P(S3)和P(S4)P(S3)","answer":0,"chooseValue":"C"},{"id":"794930337003098113","questionId":"794930335073718273","content":"V(S2)、V(S3)和P(S3)P(S4)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930317977735169","title":"<p><br/></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">进程</span>P1、P2、P3、P4、P5和P6的前趋图如下所示：</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/74ec6a38fff88e6e0f22287ae65c511e.png?x-oss-process=style/ruankaodaren\"/></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">若用</span><span style=\"font-size: 10.5pt;\">PV操作控制这6个进程的同步与互斥的程序如下，那么程序中的空①和空②处应分别为（48）</span><br/></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-size: 10.5pt;\"><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/abcc9d590714e3c42e78ad1de20522a6.png?x-oss-process=style/ruankaodaren\"/></span></span></p>","analyze":"<p><br/></p><p class=\"MsoNormal\" style=\"text-indent: 21pt; line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\">(48)根据前驱图，P2进程需要等待P1进程的通知，故需要利用P(S1)操作测试P1进程是否运行完，所以空①应填P(S1)，P2进程运行结束需要利用V操作分别通知P3、P4进程，由于P3进程执行前已经用P(S2)，所以空②应填V(S2)。</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"text-indent: 21pt; line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\"><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">参考答案：</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\">(48)</span><span style=\"font-family: 宋体; font-size: 10.5pt;\">B</span><span style=\"font-family: 宋体; font-size: 10.5pt;\"> </span></p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930319856783361"],"itemList":[{"id":"794930319844200449","questionId":"794930317977735169","content":"V(S1)和P(S2)","answer":0,"chooseValue":"A"},{"id":"794930319856783361","questionId":"794930317977735169","content":"P(S1)和V(S2)","answer":1,"chooseValue":"B"},{"id":"794930319873560577","questionId":"794930317977735169","content":"V(S1)和V(S2)","answer":0,"chooseValue":"C"},{"id":"794930319890337793","questionId":"794930317977735169","content":"V(S2)和P(S1)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930489977753601","title":"<p>某计算机系统页面大小为4K ，进程的页面变换表如下所示。若进程的逻辑地址为3D16H。该地址经过变换后，其物理地址应为( )<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/30a6c672daa8b783bda2313dc4854450.png?x-oss-process=style/ruankaodaren\" title=\"30a6c672daa8b783bda2313dc4854450.png\" alt=\"image.png\"/></p>","analyze":"<p>逻辑地3D16H共16位，页面大小为4K=2^12，也即其业内偏移地址长度为12位，才能表示4K大小页面，低12位即D16H为业内偏移，那么高4位3H为逻辑页号，在表中查找可知3对应物理块号为6，因此物理地址为6D16H。</p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930491873579009"],"itemList":[{"id":"794930491827441665","questionId":"794930489977753601","content":"2048H","answer":0,"chooseValue":"A"},{"id":"794930491840024577","questionId":"794930489977753601","content":"4096H","answer":0,"chooseValue":"B"},{"id":"794930491856801793","questionId":"794930489977753601","content":"4D16H","answer":0,"chooseValue":"C"},{"id":"794930491873579009","questionId":"794930489977753601","content":"6D16H","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930481438150657","title":"<p>下列做法中不利于嵌入式应用软件移植的是（17）。</p>","analyze":"<p>本题考查嵌入式系统的基础知识。</p><p>嵌入式应用软件是针对特定应用领域，基于某一固定的硬件平台，用来达到用户预期目标的计算机软件。由于用户任务可能有时间和精度上的要求，因此有些嵌入式应用软件需要特定嵌入式操作系统的支持。嵌入式应用软件和普通应用软件有一定的区别，它不仅要求其准确性、安全性和稳定性等方面能够满足实际应用的需要，而且还要尽可能地进行优化，以减少对系统资源的消耗，降低硬件成本。</p><p>嵌入式软件的特点有：</p><p> (1)嵌入式软件具有独特的实用性。嵌入式软件是为嵌入式系统服务的，这就要求它与外部硬件和设备联系紧密。嵌入式系统以应用为中心，根据应用需求定向开发，面向产业、面向市场，需要特定的行业经验。每种嵌入式软件都有自己独特的应用环境和实用价值。</p><p> (2)嵌入式软件应有灵活的适用性。嵌入式软件通常可以认为是一种模块化软件，它应该能非常方便灵活地运用到各种嵌入式系统中，而不能破坏或更改原有的系统特性和功能。首先它要小巧，不能占用大量资源；其次要使用灵活，应尽量优化配置，减小对系统的整体继承性，升级更换灵活方便。</p><p>综上所述，嵌入式软件和硬件平台密切相关，不同的硬件平台可能使用不同的编译器，直接使用C语言的数据类型，会引入硬件平台和软件平台带来的差异，不利于软件移植。</p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930483350753281"],"itemList":[{"id":"794930483313004545","questionId":"794930481438150657","content":"在软件设计上，采用层次化设计和模块化设计","answer":0,"chooseValue":"A"},{"id":"794930483350753281","questionId":"794930481438150657","content":"在数据类型上，尽量直接使用C语言的数据类型","answer":1,"chooseValue":"B"},{"id":"794930483388502017","questionId":"794930481438150657","content":"将不可移植的部分局域化，集中在某几个特定的文件之中","answer":0,"chooseValue":"C"},{"id":"794930483417862145","questionId":"794930481438150657","content":"软件体系结构设计时，在操作系统和应用软件之间引入一个中间件层","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930447229407233","title":"关系R、S如下图所示，关系代数表达式π1，5，6(σ1＞5(R×S))= （）。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/eda7eb3f92f9f4a0cc24510ad70c7ad6.jpg?x-oss-process=style/ruankaodaren\" title=\"eda7eb3f92f9f4a0cc24510ad70c7ad6.jpg\" alt=\"1.jpg\"/>","analyze":"<p>分析关系表达式π1，5，6(σ1＞5(R×S))：关系表达式σ1＞5(R×S)意为从关系中选取满足条件R.A大于S.B的元组，从关系R中可以看出只有元组(10，11，12)满足条件，而关系S中可以看出只有元组(3，7，11)和元组(4，7，6)满足条件，即σ1＞5(R×S)的结果如下所示。</p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/6231a4fa8fa652797b8290eb0ff08bd7.jpg?x-oss-process=style/ruankaodaren\" title=\"6231a4fa8fa652797b8290eb0ff08bd7.jpg\" alt=\"1.jpg\"/><p>π1，5，6意为投影R的第一个属性列A，S的第二个属性列B和S的第三个属性列C。从上分析可见正确的答案是选项B。</p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930449095872513"],"itemList":[{"id":"794930449074900993","questionId":"794930447229407233","content":"<img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/34684ef36424f480cc89f53184835544.jpg?x-oss-process=style/ruankaodaren\" title=\"34684ef36424f480cc89f53184835544.jpg\" alt=\"1.jpg\"/>","answer":0,"chooseValue":"A"},{"id":"794930449095872513","questionId":"794930447229407233","content":"<img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/e4c41e9d7c38e517a361e4ed0ca33e00.jpg?x-oss-process=style/ruankaodaren\" title=\"e4c41e9d7c38e517a361e4ed0ca33e00.jpg\" alt=\"2.jpg\"/>","answer":1,"chooseValue":"B"},{"id":"794930449108455425","questionId":"794930447229407233","content":"<img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/cc73b61894c2585f5da4bea8f07de5a8.jpg?x-oss-process=style/ruankaodaren\" title=\"cc73b61894c2585f5da4bea8f07de5a8.jpg\" alt=\"3.jpg\"/>","answer":0,"chooseValue":"C"},{"id":"794930449125232641","questionId":"794930447229407233","content":"<img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/6bcc0d3fa0379fe6a7bb4253638954c6.jpg?x-oss-process=style/ruankaodaren\" title=\"6bcc0d3fa0379fe6a7bb4253638954c6.jpg\" alt=\"4.jpg\"/>","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930538010923009","title":"<p>采用微内核结构的操作系统设计的基本思想是内核只完成操作系统最基本的功能并在核心态下运行，其他功能运行在用户态，其结构图如图1所示。图中空（a）、（b）、（c）和（d）应分别选择如下所示①~④中的哪一项? （1） 。</p><p>①文件和存储器服务器 ②进程调度及进程间通信 ③核心态 ④用户态</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/f78c8663280e4bcf1701901d3c8dc7e7.jpg?x-oss-process=style/ruankaodaren\" title=\"f78c8663280e4bcf1701901d3c8dc7e7.jpg\" alt=\"111.jpg\"/></p><br/>","analyze":"微内核结构（客户/服务器结构）的操作系统设计的基本思想是内核只完成操作系统最基本的功能并在核心态下运行，其他功能运行在用户态，其结构图如图2所示。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/895e1e9ba74b888819224a891193b59e.jpg?x-oss-process=style/ruankaodaren\" title=\"895e1e9ba74b888819224a891193b59e.jpg\" alt=\"111.jpg\"/>","multi":0,"questionType":1,"answer":"A","chooseItem":["794930540217126913"],"itemList":[{"id":"794930540217126913","questionId":"794930538010923009","content":"①、②、④和③","answer":1,"chooseValue":"A"},{"id":"794930540233904129","questionId":"794930538010923009","content":"④、③、②和①","answer":0,"chooseValue":"B"},{"id":"794930540263264257","questionId":"794930538010923009","content":"③、④、②和①","answer":0,"chooseValue":"C"},{"id":"794930540292624385","questionId":"794930538010923009","content":"③、①、④和②","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930332238368769","title":"<p><span style=\"font-family: 宋体; font-size: 10.5pt;\">DMA工作方式是在</span><span style=\"text-decoration:underline;\"><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">（</span>17）</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">之间建立直接的数据通路。</span></span><br/></p>","analyze":"<p><br/></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 20.7pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\">DMA方式（Direct Memory Access，也称为成组数据传送方式)，有时也称为直接内存操作。一个设备接口试图通过总线直接向另一个设备发送数据(一般是大批量的数据），它会先向CPU发送DMA请求信号，向CPU提出接管总线控制权的总线请求，CPU收到该信号后，在当前的总线周期结束后，会按DMA信号的优先级和提出DMA请求的先后顺序响应DMA信号。CPU对某个设备接口响应DMA请求时，会让出总线控制权，于是在DMA控制器的管理下，外设和存储器直接进行数据交换，而不需CPU干预。数据传送完毕后，设备接口会向CPU发送DMA结束信号，交还总线控制权。</span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 0pt; line-height: 150%;\"><span style=\"font-family: 宋体; font-size: 10.5pt; background: #7F7F7F;\"><span style=\"font-family:宋体\">参考答案</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">：</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\">C</span><strong><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></strong></p>","multi":0,"questionType":1,"answer":"C","chooseItem":["794930334113222657"],"itemList":[{"id":"794930334079668225","questionId":"794930332238368769","content":"CPU与外设","answer":0,"chooseValue":"A"},{"id":"794930334096445441","questionId":"794930332238368769","content":"CPU与主存","answer":0,"chooseValue":"B"},{"id":"794930334113222657","questionId":"794930332238368769","content":"主存与外设","answer":1,"chooseValue":"C"},{"id":"794930334125805569","questionId":"794930332238368769","content":"外设与外设","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930337930039297","title":"<p><br/></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 0pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">进程</span>P1、P2、P3、P4、P5和P6的前趋图如下所示：</span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 0pt; line-height: 150%;\"><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/8723ac560372e5adb6ff3451aaa90a82.png?x-oss-process=style/ruankaodaren\"/></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 0pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">若用</span>PV操作控制这6个进程的同步与互斥的程序如下，空d和空e处应分别为</span><span style=\"text-decoration:underline;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">（</span>47）</span></span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\">。</span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 0pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/c2b78e38cbb7ee7a322de8d86ecb63d3.png?x-oss-process=style/ruankaodaren\"/></span></p>","analyze":"<p><br/></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 20.7pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">对于试题（</span>47)，根据前驱图P4进程开始运行前必须等待P2和P3进程的通知，需要用P (S3)操作测试P2进程是否运行完，用P (S4)操作测试P3进程是否运行完，所以空d应填P (S3) P (S4), P4进程运行结束需要利用V (S6)操作通知P5进程，所以空e应填V (S6)。</span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 20.7pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\"><span style=\"font-family: 宋体; font-size: 10.5pt; background: #7F7F7F;\"><span style=\"font-family:宋体\">参考答案</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">：</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\">（47）B</span></p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930339813281793"],"itemList":[{"id":"794930339792310273","questionId":"794930337930039297","content":"V(S3)V(S4)和V(S6)","answer":0,"chooseValue":"A"},{"id":"794930339813281793","questionId":"794930337930039297","content":"P(S3)P(S4)和V(S6)","answer":1,"chooseValue":"B"},{"id":"794930339838447617","questionId":"794930337930039297","content":"P(S3)V(S4)和V(S6)","answer":0,"chooseValue":"C"},{"id":"794930339859419137","questionId":"794930337930039297","content":"P(S3)V(S4)和P(S6)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930570328035329","title":"<p>假设计算机系统的页面大小为4K，进程P的页面变换表如下表所示。若P要访问的逻辑地址为十六进制3C20H，那么该逻辑地址经过地址变换后，其物理地址应为（）。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/185ce687ff6806e682d176f05c47cdc4.png?x-oss-process=style/ruankaodaren\" title=\"185ce687ff6806e682d176f05c47cdc4.png\" alt=\"image.png\"/></p>","analyze":"<p>4K=2^12，使用十六进制表示为1000H，所以逻辑地址转换成物理地址时，后面3位不用改变，只需要改变最左边一位。对于逻辑地址3C20H，页号3对应的物理块号是6，所以物理地址为6C20H。</p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930572425187329"],"itemList":[{"id":"794930572374855681","questionId":"794930570328035329","content":"2048H","answer":0,"chooseValue":"A"},{"id":"794930572391632897","questionId":"794930570328035329","content":"3C20H","answer":0,"chooseValue":"B"},{"id":"794930572408410113","questionId":"794930570328035329","content":"5C20H","answer":0,"chooseValue":"C"},{"id":"794930572425187329","questionId":"794930570328035329","content":"6C20H","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930553450156033","title":"在支持多线程的操作系统中，假设进程 P 创建了若干个线程，那么 （6）是不能被其他线程共享的。","analyze":"<p>同一线程中可共享资源有：该进程代码段、该进程的全局变量、该进程中打开的文件、定时器、进程的当前目录和进程用户ID与进程组ID等。</p><p>不能共享的资源有：线程的栈指针、调度优先级等。</p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930555333398529"],"itemList":[{"id":"794930555291455489","questionId":"794930553450156033","content":"该进程的代码段","answer":0,"chooseValue":"A"},{"id":"794930555308232705","questionId":"794930553450156033","content":"该进程中打开的文件","answer":0,"chooseValue":"B"},{"id":"794930555320815617","questionId":"794930553450156033","content":"该进程的全局变量","answer":0,"chooseValue":"C"},{"id":"794930555333398529","questionId":"794930553450156033","content":"调度优先级","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930528066228225","title":"<p>假设计算机系统的页面大小为4K，进程P的页面变换表如下表所示。若P要动问的逻辑地址为十六进制3C20H，那么该逻辑地址经过地址变换后，其物理地址应为（）。</p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/46be690859a5650d777fea1eeceb49d3.png?x-oss-process=style/ruankaodaren\" title=\"46be690859a5650d777fea1eeceb49d3.png\" alt=\"image.png\"/>","analyze":"<p>4K=2^12，使用十六进制表示为1000H，所以逻辑地址转换成物理地址时，后面3位不用改变，只需要改变最左边一位。对于逻辑地址3C20H，页号3对应的物理块号是6，所以物理地址为6C20H。</p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930530331152385"],"itemList":[{"id":"794930530285015041","questionId":"794930528066228225","content":"2048H","answer":0,"chooseValue":"A"},{"id":"794930530297597953","questionId":"794930528066228225","content":"3C20H","answer":0,"chooseValue":"B"},{"id":"794930530314375169","questionId":"794930528066228225","content":"5C20H","answer":0,"chooseValue":"C"},{"id":"794930530331152385","questionId":"794930528066228225","content":"6C20H","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930326521532417","title":"<p><br/></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">嵌入式系统初始化过程主要有</span>3个环节，按照自底向上、从硬件到软件的次序依次为</span><span style=\"text-decoration:underline;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">（</span>51）</span></span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">。</span></span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p>","analyze":"<p><br/></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">试题解析：</span></span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">嵌入式系统初始化过程可以分为</span>3个主要环节，按照自底向上、从硬件到软件的次序依次为：片级初始化、板级初始化和系统级初始化。</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\">①片级初始化：完成嵌入式微处理器的初始化，包括设置嵌入式微处理器的核心寄存器和控制寄存器、嵌入式微处理器核心工作模式和嵌入式微处理器的局部总线模式等。片级初始化把嵌入式微处理器从上电时的默认状态逐步设置成系统所要求的工作状态。这是一个纯硬件的初始化过程。</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\">②板级初始化：完成嵌入式微处理器以外的其他硬件设备的初始化。另外，还需设置某些软件的数据结构和参数，为随后的系统级初始化和应用程序的运行建立硬件和软件环境。这是一个同时包含软硬件两部分在内的初始化过程。</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\">③系统初始化：该初始化过程以软件初始化为主，主要进行操作系统的初始化。BSP将对嵌入式微处理器的控制权转交给嵌入式操作系统，由操作系统完成余下的初始化操作，包含加载和初始化与硬件无关的设备驱动程序，建立系统内存区，加载并初始化其他系统软件模块，如网络系统、文件系统等。最后，操作系统创建应用程序环境，并将控制权交给应用程序的入口。</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">参考答案：</span></span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\">(51)</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\">B</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930328404774913"],"itemList":[{"id":"794930328387997697","questionId":"794930326521532417","content":"片级初始化→系统级初始化→板级初始化","answer":0,"chooseValue":"A"},{"id":"794930328404774913","questionId":"794930326521532417","content":"片级初始化→板级初始化→系统级初始化","answer":1,"chooseValue":"B"},{"id":"794930328421552129","questionId":"794930326521532417","content":"系统级初始化→板级初始化→片级初始化","answer":0,"chooseValue":"C"},{"id":"794930328438329345","questionId":"794930326521532417","content":"系统级初始化→片级初始化→板级初始化","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930498504773633","title":"<p>实时操作系统中，外部事件必须（ ）</p>","analyze":"<p>实时是规定的时间内做出正确的回应。</p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930500434153473"],"itemList":[{"id":"794930500362850305","questionId":"794930498504773633","content":"一个时间片内处理","answer":0,"chooseValue":"A"},{"id":"794930500388016129","questionId":"794930498504773633","content":"一个周期时间内处理","answer":0,"chooseValue":"B"},{"id":"794930500413181953","questionId":"794930498504773633","content":"一个机器周期内处理","answer":0,"chooseValue":"C"},{"id":"794930500434153473","questionId":"794930498504773633","content":"被控对象允许的时间内","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930408495009793","title":"设指令由取指、分析、执行3个子部件完成，并且每个子部件的时间均为△t。若采用常规标量单流水线处理机（即该处理机的度为1），连续执行12条指令，共需 （ ） △t。若采用度为4的超标量流水线处理机，连续执行上述12条指令，只需（请作答此空）△t。","analyze":"<p>指令由取指、分析和执行3个子部件完成，n=3，且每个子部件的时间均为Δt。若采用常规标量单流水线处理机（即该处理机的度m=1），连续执行12条（k=12）指令的时空图如图所示。执行这12条指令所需的总时间为：Tk=（k+3-1）*Δt=（12+3）*Δt=14Δt。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/90dfd6141eacf0f7ed9d3fb019ff76ba.jpg?x-oss-process=style/ruankaodaren\" title=\"90dfd6141eacf0f7ed9d3fb019ff76ba.jpg\" alt=\"1.jpg\"/></p><p>若采用度为4（m=4）的超标量流水线处理机，连续执行上述12条（k=12）指令的时空图如图所示。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/257b5f227f575d5943e4c9c4ca75c7f2.jpg?x-oss-process=style/ruankaodaren\" title=\"257b5f227f575d5943e4c9c4ca75c7f2.jpg\" alt=\"2.jpg\"/></p><p>由图可知，执行这12条指令所需的总时间只需要5Δt。</p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930410365669377"],"itemList":[{"id":"794930410348892161","questionId":"794930408495009793","content":"3","answer":0,"chooseValue":"A"},{"id":"794930410365669377","questionId":"794930408495009793","content":"5","answer":1,"chooseValue":"B"},{"id":"794930410382446593","questionId":"794930408495009793","content":"7","answer":0,"chooseValue":"C"},{"id":"794930410399223809","questionId":"794930408495009793","content":"9","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930399921852417","title":"<p>某文件系统采用多级索引结构，若磁盘块的大小为4 KB字节，每个块号需占4字节，那么采用二级索引结构时的文件最大长度可占用（ ）个物理块。</p>","analyze":"<p>本题考查索引文件结构，在索引文件结构中，二级间接索引是指索引节点对应的盘块保存索引表，在索引表指向的盘块中依然保存索引表。由于每个索引表可以存4 KB/4=1024个块号，所以二级索引可对应1024×1024个物理块。</p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930401805094913"],"itemList":[{"id":"794930401792512001","questionId":"794930399921852417","content":"1024","answer":0,"chooseValue":"A"},{"id":"794930401805094913","questionId":"794930399921852417","content":"1024×1024","answer":1,"chooseValue":"B"},{"id":"794930401817677825","questionId":"794930399921852417","content":"2048×2048","answer":0,"chooseValue":"C"},{"id":"794930401834455041","questionId":"794930399921852417","content":"4096×4096","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930391365472257","title":"<p>在磁盘调度管理中，应先进行移臂调度，再进行旋转调度。假设磁盘移动臂位于21号柱面上，进程的请求序列如下表所示。如果采用最短移臂调度算法，那么系统的响应序列应为（ ）。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/6d5b6dff4545d10d43d3702616fd8b6f.jpg?x-oss-process=style/ruankaodaren\" title=\"6d5b6dff4545d10d43d3702616fd8b6f.jpg\" alt=\"1.jpg\"/></p>","analyze":"<p>根据题干要求，先进行移臂调度，找到对应柱面。然后进行旋转调度，找到对应磁头和扇区。</p><p>由表可知①⑤⑦在17柱面（21-17=4），②③⑧在23柱面（23-21=2），④⑥在32柱面（32-21=9）。因此按最短移臂算法，应该是23柱面→17柱面→32柱面→38柱面，只有D项满足。</p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930393261297665"],"itemList":[{"id":"794930393210966017","questionId":"794930391365472257","content":"②⑧③④⑤①⑦⑥⑨","answer":0,"chooseValue":"A"},{"id":"794930393231937537","questionId":"794930391365472257","content":"②③⑧④⑥⑨①⑤⑦","answer":0,"chooseValue":"B"},{"id":"794930393248714753","questionId":"794930391365472257","content":"①②③④⑤⑥⑦⑧⑨","answer":0,"chooseValue":"C"},{"id":"794930393261297665","questionId":"794930391365472257","content":"②⑧③⑤⑦①④⑥⑨","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930438744330241","title":"嵌入式系统硬件初始化过程分为3个主要环节，按照自下而上、从硬件到软件的次序依次是（）","analyze":"嵌入式系统硬件初始化是设计一个完整的板级支持包(BSP)需要完成的工作之一，它可以分为3个主要环节，按照自底向上、从硬件到软件的次序依次为：①片级初始化；②板级初始化；③系统级初始化，详细描述如下表所示。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/72399f4e1e0f939a5d0a46e8abda4e7d.jpg?x-oss-process=style/ruankaodaren\" title=\"72399f4e1e0f939a5d0a46e8abda4e7d.jpg\" alt=\"1.jpg\"/>","multi":0,"questionType":1,"answer":"C","chooseItem":["794930440652738561"],"itemList":[{"id":"794930440610795521","questionId":"794930438744330241","content":"板级→系统级→片级","answer":0,"chooseValue":"A"},{"id":"794930440631767041","questionId":"794930438744330241","content":"系统级→板级→片级","answer":0,"chooseValue":"B"},{"id":"794930440652738561","questionId":"794930438744330241","content":"片级→板级→系统级","answer":1,"chooseValue":"C"},{"id":"794930440677904385","questionId":"794930438744330241","content":"系统级→片级→板级","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930550514143233","title":"某系统中有6个并发进程竞争资源R。假设每个进程都需要3个R，那么最少需要有 （5） 个R，才能保证系统不会发生死锁。","analyze":"至少需要资源数=并发进程数×(每个进程所需资源数-1)+1=6×(3-1)+1=13","multi":0,"questionType":1,"answer":"D","chooseItem":["794930552539992065"],"itemList":[{"id":"794930552451911681","questionId":"794930550514143233","content":"10","answer":0,"chooseValue":"A"},{"id":"794930552485466113","questionId":"794930550514143233","content":"11","answer":0,"chooseValue":"B"},{"id":"794930552514826241","questionId":"794930550514143233","content":"12","answer":0,"chooseValue":"C"},{"id":"794930552539992065","questionId":"794930550514143233","content":"13","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930357928480769","title":"<p><span style=\"font-family:宋体\">以下关于程序访问局部性原理的叙述，错误的是</span><span style=\"font-family: Calibri; font-size: 12pt;\"> </span><span style=\"font-family:宋体\">（</span><span style=\"font-family:Calibri\"> </span><span style=\"font-family:宋体\">） 。</span></p><p class=\"p\"><br/></p>","analyze":"<p><br/></p><p class=\"p\"><span style=\"font-family: Calibri; font-size: 12pt;\"><span style=\"font-family:宋体\">本题考查存储系统知识。</span></span><span style=\"font-family: Calibri; font-size: 12pt;\"></span></p><p class=\"p\"><span style=\"font-family: Calibri; font-size: 12pt;\"><span style=\"font-family:宋体\">程序访问的局部性原理包含量方面的含义：一是时间局部性，指程序在最近的未来要用到的信息肯可能是现在正在使用的信息；二是空间局部性，指最近的未来要用到的信息与现在正在使用的信息很可能在空间上是相邻的或相近的，这是因为程序中大多数指令是顺序存放且顺序执行的，数据一般也是聚簇存储在一起的。</span></span><span style=\"font-family: Calibri; font-size: 12pt;\"></span></p><p class=\"p\"><span style=\"font-family: Calibri; font-size: 12pt;\"><span style=\"font-family:宋体\">程序访问局部性原理是存储层次得以构成和管理的主要依据。根据该原理，可以把空间位置相临近的信息作为一</span>“<span style=\"font-family:宋体\">块</span><span style=\"font-family:Calibri\">”</span><span style=\"font-family:宋体\">放到容量最小的第一级存储器</span><span style=\"font-family:Calibri\">M1</span><span style=\"font-family:宋体\">中，在最近未来的一段时间内多次连续访存很可能都在</span><span style=\"font-family:Calibri\">M1</span><span style=\"font-family:宋体\">的同一</span><span style=\"font-family:Calibri\">“</span><span style=\"font-family:宋体\">块</span><span style=\"font-family:Calibri\">”</span><span style=\"font-family:宋体\">中，从而使整个存储系统的访问速度接近于</span><span style=\"font-family:Calibri\">M1</span><span style=\"font-family:宋体\">的速度。</span></span><span style=\"font-family: Calibri; font-size: 12pt;\"></span></p><p class=\"p\"><strong><span class=\"15\" style=\"font-family: "Times New Roman";\"><span style=\"font-family:宋体\">答案</span></span></strong><span style=\"font-family: Calibri; font-size: 12pt;\">D </span></p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930359841083393"],"itemList":[{"id":"794930359794946049","questionId":"794930357928480769","content":"程序访问具有时间局部性，即最近将要用的信息很可能是正在使用的信息","answer":0,"chooseValue":"A"},{"id":"794930359815917569","questionId":"794930357928480769","content":"程序访问具有空间局部性，即最近将要用的信息很可能与正在使用的信息在存储空间上是相邻的","answer":0,"chooseValue":"B"},{"id":"794930359828500481","questionId":"794930357928480769","content":"程序访问局部性是构成层次结构的存储系统的主要依据","answer":0,"chooseValue":"C"},{"id":"794930359841083393","questionId":"794930357928480769","content":"程序访问局部性是确定存储系统的性能指标（命中率、平均访问时间、访问效率等）的主要依据","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930323702960129","title":"<p><br/></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">进程</span>P1、P2、P3、P4、P5和P6的前趋图如下所示：</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/d0d6bb6e44064d58952c87e53467f49b.png?x-oss-process=style/ruankaodaren\"/></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">若用</span>PV操作控制这6个进程的同步与互斥的程序如下，空⑤和空⑥处应分别为（50）。</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/b21bd0b9cd39581d754e9db7ba267a10.png?x-oss-process=style/ruankaodaren\"/></span></p>","analyze":"<p><br/></p><p class=\"MsoNormal\" style=\"text-indent: 21pt; line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">根据前驱图</span>P4、P5进程执行完都需要通知P6进程，P6进程运行前执行了P(S6)和P(S7)，而P5进程执行完后执行了V(S7)，故P4进程应该执行V(S6)，即空⑤应填V(S6)。又因为P5进程开始运行前必须等待P3进程的通知，需要用P(S5)操作测试P3进程是否运行完。故空⑥应填写P(S5)。</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">参考答案：</span></span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\">(50)</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"> D</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930325611368449"],"itemList":[{"id":"794930325561036801","questionId":"794930323702960129","content":"P(S6)和V(S5)","answer":0,"chooseValue":"A"},{"id":"794930325582008321","questionId":"794930323702960129","content":"P(S6)和P(S5)","answer":0,"chooseValue":"B"},{"id":"794930325594591233","questionId":"794930323702960129","content":"V(S5)和V(S6)","answer":0,"chooseValue":"C"},{"id":"794930325611368449","questionId":"794930323702960129","content":"V(S6)和P(S5)","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930435913175041","title":"以下关于嵌入式系统的软件设计的描述中，说法错误的是（）。","analyze":"<p>在嵌入式开发过程中有主机和目标机的角se之分。主机是执行编译、链接和定址过程的计算机；目标机是指运行嵌入式软件的硬件平台。首先须把应用程序转换成可以在目标机上运行的二进制代码。这一过程包含3个步骤，分别为编译、链接和定址。</p><p>①编译过程由交叉编译器实现。所谓交叉编译器就是运行在一个计算机平台上并为另一个平台产生代码的编译器。</p><p>②编译过程产生的所有目标文件被链接成一个目标文件，称为链接过程。</p><p>③定址过程会把物理存储器地址指定给目标文件的每个相对偏移处。该过程生成的文件就是可以在嵌入式平台上执行的二进制文件。</p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930437783834625"],"itemList":[{"id":"794930437767057409","questionId":"794930435913175041","content":"把应用程序转换成可以在目标机上运行的二进制代码，通常需要经过编译、链接和定址等3个步骤","answer":0,"chooseValue":"A"},{"id":"794930437783834625","questionId":"794930435913175041","content":"编译过程生成的文件就是可以在嵌入式平台上执行的二进制文件","answer":1,"chooseValue":"B"},{"id":"794930437804806145","questionId":"794930435913175041","content":"定址过程会把物理存储器地址指定给目标文件的每个相对偏移处","answer":0,"chooseValue":"C"},{"id":"794930437821583361","questionId":"794930435913175041","content":"编译过程产生的所有目标文件被链接成一个目标文件","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930363553042433","title":"<p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/e6defefcec379b19ffe2b14349aa23fc.png?x-oss-process=style/ruankaodaren\"/></p>","analyze":"<p><span style=\"text-indent: 20.7pt; font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">本题考查操作系统中</span>PV<span style=\"font-family:宋体\">操作知识点。信号量是一个整型变量，根据控制对象的不同赋不同的值。信号量可分为两类。公用信号量：实现进程间的互斥，初值为资源的数目。私用信号量：实现进程间的同步，初值</span></span><span style=\"text-indent: 20.7pt; font-family: Calibri; font-size: 10.5pt;\">=0</span><span style=\"text-indent: 20.7pt; font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">或某个整数。</span></span><br/></p><p class=\"MsoNormal\" style=\"text-indent:20.7000pt;\"><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">本题中</span>PV<span style=\"font-family:宋体\">操作顺序如下：</span></span><span style=\"mso-spacerun:'yes';font-family:Calibri;mso-fareast-font-family:宋体;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"text-indent:20.7000pt;\"><span style=\"mso-spacerun:'yes';font-family:Calibri;mso-fareast-font-family:宋体;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\">Begin</span><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"> BeginP1<span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">V(S1)</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">end</span><span style=\"font-family:宋体\">；题目中</span><span style=\"font-family:Calibri\">a</span><span style=\"font-family:宋体\">处填写</span><span style=\"font-family:Calibri\">V(S1)</span><span style=\"font-family:宋体\">；</span></span><span style=\"mso-spacerun:'yes';font-family:Calibri;mso-fareast-font-family:宋体;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"text-indent:20.7000pt;\"><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\">BeginP(S1)<span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">P2</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">V(S2)</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">V(S3)</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">end</span><span style=\"font-family:宋体\">；题目中</span><span style=\"font-family:Calibri\">b</span><span style=\"font-family:宋体\">处填写</span><span style=\"font-family:Calibri\">P(S1)</span><span style=\"font-family:宋体\">，</span><span style=\"font-family:Calibri\">c</span><span style=\"font-family:宋体\">处填写</span><span style=\"font-family:Calibri\">V(S2)</span><span style=\"font-family:宋体\">和</span><span style=\"font-family:Calibri\">V(S3)BeginP(S2)</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">P3</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">V(S4)</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">end</span><span style=\"font-family:宋体\">；题目中</span><span style=\"font-family:Calibri\">d</span><span style=\"font-family:宋体\">处填写</span><span style=\"font-family:Calibri\">P(S2)</span><span style=\"font-family:宋体\">，</span><span style=\"font-family:Calibri\">e</span><span style=\"font-family:宋体\">处填写</span><span style=\"font-family:Calibri\">V(S4)</span></span><span style=\"mso-spacerun:'yes';font-family:Calibri;mso-fareast-font-family:宋体;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"text-indent:20.7000pt;\"><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\">BeginP(S3)<span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">P4</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">V(S5)</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">end</span><span style=\"font-family:宋体\">；题目中</span><span style=\"font-family:Calibri\">f</span><span style=\"font-family:宋体\">处填写</span><span style=\"font-family:Calibri\">P(S3)</span><span style=\"font-family:宋体\">，</span></span><span style=\"mso-spacerun:'yes';font-family:Calibri;mso-fareast-font-family:宋体;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"text-indent:20.7000pt;\"><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\">BeginP(S4)<span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">P(S5);P5</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">end</span><span style=\"font-family:宋体\">；题目中</span><span style=\"font-family:Calibri\">g</span><span style=\"font-family:宋体\">处填写</span><span style=\"font-family:Calibri\">P(S4)</span><span style=\"font-family:宋体\">和</span><span style=\"font-family:Calibri\">P(S5)</span><span style=\"font-family:宋体\">。得到本题选项。</span></span><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930365465645057"],"itemList":[{"id":"794930365444673537","questionId":"794930363553042433","content":"V(S2)和P(S4)","answer":0,"chooseValue":"A"},{"id":"794930365465645057","questionId":"794930363553042433","content":"P(S2)和V(S4)","answer":1,"chooseValue":"B"},{"id":"794930365490810881","questionId":"794930363553042433","content":"P(S2)和P(S4)","answer":0,"chooseValue":"C"},{"id":"794930365511782401","questionId":"794930363553042433","content":"V(S2)和V(S4)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930372260417537","title":"<p><span style=\"font-family:宋体\">系统级初始化主要任务是（</span><span style=\"font-family:Calibri\">28</span><span style=\"font-family:宋体\">）。</span><br/></p><p class=\"MsoNormal\" style=\"text-indent:20.7000pt;\"><br/></p>","analyze":"<p><br/></p><p class=\"MsoNormal\" style=\"text-indent:20.7000pt;\"><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">系统初始化过程可以分为</span>3<span style=\"font-family:宋体\">个主要环节，按照自底向上、从硬件到软件的次序依次为：片级初始化、板级初始化和系统级初始化。</span></span><span style=\"mso-spacerun:'yes';font-family:Calibri;mso-fareast-font-family:宋体;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"text-indent:20.7000pt;\"><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">系统初始化：该初始化过程以软件初始化为主，主要进行操作系统的初始化。</span></span><span style=\"mso-spacerun:'yes';font-family:Calibri;mso-fareast-font-family:宋体;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\">BSP</span><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">将对嵌入式微处理器的控制权转交给嵌入式操作系统，由操作系统完成余下的初始化操作，包含加载和初始化与硬件无关的设备驱动程序，建立系统内存区，加载并初始化其他系统软件模块，如网络系统、文件系统等。最后，操作系统创建应用程序环境，并将控制权交给应用程序的入口。</span></span><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p>","multi":0,"questionType":1,"answer":"C","chooseItem":["794930374160437249"],"itemList":[{"id":"794930374126882817","questionId":"794930372260417537","content":"完成嵌入式微处理器的初始化","answer":0,"chooseValue":"A"},{"id":"794930374143660033","questionId":"794930372260417537","content":"完成嵌入式微处理器以外的其他硬件设备的初始化","answer":0,"chooseValue":"B"},{"id":"794930374160437249","questionId":"794930372260417537","content":"以软件初始化为主，主要进行操作系统的初始化","answer":1,"chooseValue":"C"},{"id":"794930374177214465","questionId":"794930372260417537","content":"设置嵌入式微处理器的核心寄存器和控制寄存器工作状态","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930355114102785","title":"<p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/2a0a409aae5d02c3829fa523612d6b33.png?x-oss-process=style/ruankaodaren\"/></p>","analyze":"<p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/31e819073e3f9543ce797a330cd82d20.png?x-oss-process=style/ruankaodaren\"/></p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930356972179457"],"itemList":[{"id":"794930356955402241","questionId":"794930355114102785","content":"P（S4）和V（S4）V（S5）","answer":0,"chooseValue":"A"},{"id":"794930356972179457","questionId":"794930355114102785","content":"V（S5）和P（S4）P（S5）","answer":1,"chooseValue":"B"},{"id":"794930356993150977","questionId":"794930355114102785","content":"V（S3）和V（S4）V（S5）","answer":0,"chooseValue":"C"},{"id":"794930357014122497","questionId":"794930355114102785","content":"P（S3）和P（S4）V（P5）","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930329361076225","title":"<p><br/></p><p class=\"MsoNormal\"><span style=\"mso-spacerun:'yes';font-family:宋体;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">按照</span>Cache地址映像的块冲突概率，从高到低排列的是</span><span style=\"text-decoration:underline;\"><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">（</span>15）</span></span><span style=\"mso-spacerun:'yes';font-family:宋体;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">。</span></span></p>","analyze":"<p><br/></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 20.7pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">直接映像是指在进行映像的工作时，规定各区中的某一信息块只能映像到</span>Cache中的一个固定的信息块中</span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">。</span></span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 21pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">全相联映像是指主存中的每一个字块可映像到</span>Cache任何一个字块位置上。</span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 21pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">组相联映像方式是直接映像和全相联映像的一种折衷方案</span></span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">，</span></span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">这种方法将存储空间分为若干组，各组之间是直接映像，而组内各块之间则是全相联映像。</span></span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 21pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">进行地址映像时，直接映像方式下冲突概率最高，全相联映像方式下冲突概率最低。</span></span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"margin-left: 0pt; text-indent: 0pt; line-height: 150%;\"><span style=\"font-family: 宋体; font-size: 10.5pt; background: #7F7F7F;\"><span style=\"font-family:宋体\">参考答案</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">：</span></span><span style=\"font-family: 宋体; font-size: 10.5pt;\">B</span><strong><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></strong></p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930331273678849"],"itemList":[{"id":"794930331231735809","questionId":"794930329361076225","content":"全相联映像→直接映像→组相联映像","answer":0,"chooseValue":"A"},{"id":"794930331273678849","questionId":"794930329361076225","content":"直接映像→组相联映像→全相联映像","answer":1,"chooseValue":"B"},{"id":"794930331298844673","questionId":"794930329361076225","content":"组相联映像→全相联映像→直接映像","answer":0,"chooseValue":"C"},{"id":"794930331319816193","questionId":"794930329361076225","content":"直接映像→全相联映像→组相联映像","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930394188238849","title":"<p>某计算机系统中的进程管理采用三态模型，那么下图所示的PCB（进程控制块）的组织方式采用（请作答此空），图中（）。</p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/ed31f0ccfca66539d30e5880ca6f52e8.jpg?x-oss-process=style/ruankaodaren\" title=\"ed31f0ccfca66539d30e5880ca6f52e8.jpg\" alt=\"1.jpg\"/>","analyze":"<p>进程控制块PCB的组织方式如下。</p><p>（1） 线性表方式：不论进程的状态如何，将所有的PCB连续地存放在内存的系统区，这种方式适用于系统中进程数目不多的情况。</p><p>（2） 索引表方式：该方式是线性表方式的改进，系统按照进程的状态分别建立就绪索引表、阻塞索引表等。</p><p>（3） 链接表方式：系统按照进程的状态将进程的PCB组成队列，从而形成就绪队列、阻塞队列、运行队列等。</p><p>运行进程为PCB1、PCB3；就绪进程为PCB2、PCB4、PCB5；阻塞进程为PCB6、PCB7、PCB8、PCB9。</p>","multi":0,"questionType":1,"answer":"C","chooseItem":["794930396075675649"],"itemList":[{"id":"794930396042121217","questionId":"794930394188238849","content":"顺序方式","answer":0,"chooseValue":"A"},{"id":"794930396058898433","questionId":"794930394188238849","content":"链接方式","answer":0,"chooseValue":"B"},{"id":"794930396075675649","questionId":"794930394188238849","content":"索引方式","answer":1,"chooseValue":"C"},{"id":"794930396092452865","questionId":"794930394188238849","content":"Hash","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930369374736385","title":"<p><span style=\"font-family:宋体\">嵌入式系统初始化过程主要有</span><span style=\"font-family: 宋体; font-size: 10.5pt; text-indent: 20.7pt;\">3</span><span style=\"font-family:宋体\">个环节，按照自底向上、从硬件到软件的次序依次为（</span><span style=\"font-family:Calibri\"> </span><span style=\"font-family:宋体\">）。</span></p>","analyze":"<p><span style=\"font-family:宋体\">系统初始化过程可以分为</span><span style=\"font-family: 宋体; font-size: 10.5pt; text-indent: 20.7pt;\">3</span><span style=\"font-family:宋体\">个主要环节，按照自底向上、从硬件到软件的次序依次为：片级初始化、板级初始化和系统级初始化。</span><br/></p><p class=\"MsoNormal\" style=\"text-indent:20.7000pt;\"><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">系统初始化：该初始化过程以软件初始化为主，主要进行操作系统的初始化。</span></span><span style=\"mso-spacerun:'yes';font-family:Calibri;mso-fareast-font-family:宋体;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\">BSP</span><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">将对嵌入式微处理器的控制权转交给嵌入式操作系统，由操作系统完成余下的初始化操作，包含加载和初始化与硬件无关的设备驱动程序，建立系统内存区，加载并初始化其他系统软件模块，如网络系统、文件系统等。最后，操作系统创建应用程序环境，并将控制权交给应用程序的入口。</span></span><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930371316699137"],"itemList":[{"id":"794930371299921921","questionId":"794930369374736385","content":"片级初始化→系统级初始化→板级初始化","answer":0,"chooseValue":"A"},{"id":"794930371316699137","questionId":"794930369374736385","content":"片级初始化→板级初始化→系统级初始化","answer":1,"chooseValue":"B"},{"id":"794930371329282049","questionId":"794930369374736385","content":"系统级初始化→板级初始化→片级初始化","answer":0,"chooseValue":"C"},{"id":"794930371346059265","questionId":"794930369374736385","content":"系统级初始化→片级初始化→板级初始化","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930515504287745","title":"<p>前趋图(Precedence Graph)是一个有向无环图，记为:→= {(Pi，Pj)Pi must complete before Pj may start}。假设系统中进程P={P1，P2，P3，P4，P5，P6，P7，P8}，且进程的前驱图如下:</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/6edd9d9ad078ae95837c1872aa67f821.png?x-oss-process=style/ruankaodaren\" title=\"6edd9d9ad078ae95837c1872aa67f821.png\" alt=\"image.png\"/><br/></p><p>那么，该前驱图可记为（ ）。</p><p><br/></p>","analyze":"<p>(Pi，Pj)表示前驱图的一个进程之间的逻辑关系，该图一共有11个逻辑关系。记为→={(P1，P2)，(P1，P3)，(P2，P3)，(P2，P5)，(P3，P6)，(P3，P4)，(P4，P7)，(P5，P6)，(P6，P7)，(P6，P8)， (P7， P8) }</p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930517437861889"],"itemList":[{"id":"794930517391724545","questionId":"794930515504287745","content":"→={(P1，P2)，(P1，P3)，(P1，P4)，(P2，P5)，(P3，P5)，(P4，P7)，(P5，P6)，(P6，P7)，(P6，P8)，(P7，P8)}","answer":0,"chooseValue":"A"},{"id":"794930517408501761","questionId":"794930515504287745","content":"→={(P1，P2)，(P3，P1)，(P4，P1)，(P5，P2)，(P5，P3)，(P6，P4)，(P7，P5)，(P7，P6)，(P6，P8)，(P8，P7)}","answer":0,"chooseValue":"B"},{"id":"794930517421084673","questionId":"794930515504287745","content":"→={(P1，P2)，(P1，P3)，(P1，P4)，(P2，P5)，(P3，P6)，(P4，P7)，(P5，P6)，(P6，P7)，(P6，P8)，(P7，P8)}","answer":0,"chooseValue":"C"},{"id":"794930517437861889","questionId":"794930515504287745","content":"→={(P1，P2)，(P1，P3)，(P2，P3)，(P2，P5)，(P3，P6)，(P3，P4)，(P4，P7)，(P5，P6)，(P6，P7)，(P6，P8)， (P7， P8) }","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930464400887809","title":"<p>嵌入式系统由硬件部分和软件部分构成。以下不属于嵌入式系统软件的是（1）。</p>","analyze":"<p><br/></p><p>嵌入式系统由硬件部分和软件部分构成。通常将嵌入式软件分为：①嵌入式系统软件；②嵌入式应用软件；③嵌入式支撑软件等3大类。每类软件的功能及应用实例如下表所示。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/192f935f8bed1429776f03b625d79c45.jpg?x-oss-process=style/ruankaodaren\" title=\"192f935f8bed1429776f03b625d79c45.jpg\" alt=\"1.jpg\"/></p><br/>","multi":0,"questionType":1,"answer":"A","chooseItem":["794930466246381569"],"itemList":[{"id":"794930466246381569","questionId":"794930464400887809","content":"系统内核","answer":1,"chooseValue":"A"},{"id":"794930466271547393","questionId":"794930464400887809","content":"驱动程序","answer":0,"chooseValue":"B"},{"id":"794930466296713217","questionId":"794930464400887809","content":"FPGA编程软件","answer":0,"chooseValue":"C"},{"id":"794930466313490433","questionId":"794930464400887809","content":"嵌入式中间件","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930366421946369","title":"<p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/23794eef1fdca03aa1c299e27abab526.png?x-oss-process=style/ruankaodaren\"/></p>","analyze":"<p><span style=\"text-indent: 20.7pt; font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">本题考查操作系统中</span>PV<span style=\"font-family:宋体\">操作知识点。信号量是一个整型变量，根据控制对象的不同赋不同的值。信号量可分为两类。公用信号量：实现进程间的互斥，初值为资源的数目。私用信号量：实现进程间的同步，初值</span></span><span style=\"text-indent: 20.7pt; font-family: Calibri; font-size: 10.5pt;\">=0</span><span style=\"text-indent: 20.7pt; font-family: 宋体; font-size: 10.5pt;\"><span style=\"font-family:宋体\">或某个整数。</span></span><br/></p><p class=\"MsoNormal\" style=\"text-indent:20.7000pt;\"><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">本题中</span>PV<span style=\"font-family:宋体\">操作顺序如下：</span></span><span style=\"mso-spacerun:'yes';font-family:Calibri;mso-fareast-font-family:宋体;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"text-indent:20.7000pt;\"><span style=\"mso-spacerun:'yes';font-family:Calibri;mso-fareast-font-family:宋体;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\">Begin</span><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"> BeginP1<span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">V(S1)</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">end</span><span style=\"font-family:宋体\">；题目中</span><span style=\"font-family:Calibri\">a</span><span style=\"font-family:宋体\">处填写</span><span style=\"font-family:Calibri\">V(S1)</span><span style=\"font-family:宋体\">；</span></span><span style=\"mso-spacerun:'yes';font-family:Calibri;mso-fareast-font-family:宋体;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"text-indent:20.7000pt;\"><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\">BeginP(S1)<span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">P2</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">V(S2)</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">V(S3)</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">end</span><span style=\"font-family:宋体\">；题目中</span><span style=\"font-family:Calibri\">b</span><span style=\"font-family:宋体\">处填写</span><span style=\"font-family:Calibri\">P(S1)</span><span style=\"font-family:宋体\">，</span><span style=\"font-family:Calibri\">c</span><span style=\"font-family:宋体\">处填写</span><span style=\"font-family:Calibri\">V(S2)</span><span style=\"font-family:宋体\">和</span><span style=\"font-family:Calibri\">V(S3)BeginP(S2)</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">P3</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">V(S4)</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">end</span><span style=\"font-family:宋体\">；题目中</span><span style=\"font-family:Calibri\">d</span><span style=\"font-family:宋体\">处填写</span><span style=\"font-family:Calibri\">P(S2)</span><span style=\"font-family:宋体\">，</span><span style=\"font-family:Calibri\">e</span><span style=\"font-family:宋体\">处填写</span><span style=\"font-family:Calibri\">V(S4)</span></span><span style=\"mso-spacerun:'yes';font-family:Calibri;mso-fareast-font-family:宋体;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"text-indent:20.7000pt;\"><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\">BeginP(S3)<span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">P4</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">V(S5)</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">end</span><span style=\"font-family:宋体\">；题目中</span><span style=\"font-family:Calibri\">f</span><span style=\"font-family:宋体\">处填写</span><span style=\"font-family:Calibri\">P(S3)</span><span style=\"font-family:宋体\">，</span></span><span style=\"mso-spacerun:'yes';font-family:Calibri;mso-fareast-font-family:宋体;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"text-indent:20.7000pt;\"><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\">BeginP(S4)<span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">P(S5);P5</span><span style=\"font-family:宋体\">；</span><span style=\"font-family:Calibri\">end</span><span style=\"font-family:宋体\">；题目中</span><span style=\"font-family:Calibri\">g</span><span style=\"font-family:宋体\">处填写</span><span style=\"font-family:Calibri\">P(S4)</span><span style=\"font-family:宋体\">和</span><span style=\"font-family:Calibri\">P(S5)</span><span style=\"font-family:宋体\">。得到本题选项。</span></span><span style=\"mso-spacerun:'yes';font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:'Times New Roman';font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p>","multi":0,"questionType":1,"answer":"C","chooseItem":["794930368410046465"],"itemList":[{"id":"794930368376492033","questionId":"794930366421946369","content":"P(S3)和V(S4)V(S5)","answer":0,"chooseValue":"A"},{"id":"794930368393269249","questionId":"794930366421946369","content":"V(S3)和P(S4)P(S5)","answer":0,"chooseValue":"B"},{"id":"794930368410046465","questionId":"794930366421946369","content":"P(S3)和P(S4)P(S5)","answer":1,"chooseValue":"C"},{"id":"794930368422629377","questionId":"794930366421946369","content":"V(S3)和V(S4)V(S5)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930349460180993","title":"<p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/78a5fbbbe9e8e65bbdda2363d6369617.png?x-oss-process=style/ruankaodaren\"/></p>","analyze":"<p>略<br/></p>","multi":0,"questionType":1,"answer":"C","chooseItem":["794930351368589313"],"itemList":[{"id":"794930351318257665","questionId":"794930349460180993","content":"V（S1）P（S2）和V（S3）","answer":0,"chooseValue":"A"},{"id":"794930351347617793","questionId":"794930349460180993","content":"P（S1）V（S2）和V（S3）","answer":0,"chooseValue":"B"},{"id":"794930351368589313","questionId":"794930349460180993","content":"V（S1）V（S2）和V（S3）","answer":1,"chooseValue":"C"},{"id":"794930351393755137","questionId":"794930349460180993","content":"P（S1）P（S2）和V（S3）","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930504179666945","title":"某文件系统采用链式存储管理方案，磁盘块的大小为1024字节。文件Myfile.doc由5个逻辑记录组成，每个逻辑记录的大小与磁盘块的大小相等，并依次存放在121、75、86、65和114号磁盘块上。若需要存取文件的第5120逻辑字节处的信息，应该访问（ ） 号磁盘块。","analyze":"每个逻辑记录的大小与磁盘块的大小相等(1024字节)，而需要存取文件的第5120逻辑字节处的信息，由计算得5120=1024*5，即该处信息在第5个逻辑记录上，对应的是114号磁盘块。","multi":0,"questionType":1,"answer":"D","chooseItem":["794930506083880961"],"itemList":[{"id":"794930506025160705","questionId":"794930504179666945","content":"7","answer":0,"chooseValue":"A"},{"id":"794930506046132225","questionId":"794930504179666945","content":"85","answer":0,"chooseValue":"B"},{"id":"794930506062909441","questionId":"794930504179666945","content":"65","answer":0,"chooseValue":"C"},{"id":"794930506083880961","questionId":"794930504179666945","content":"114","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930573373100033","title":"<p><strong>请作答第<span style=\"color: red\">1</span>空。</strong></p><p>某文件系统采用索引节点管理，其磁盘索引块和磁盘数据块大小均为1KB且每个文件索引节点有8个地址项iaddr[0]～iaddr[7]，每个地址项大小为4字节，其中iaddr[0]～iaddr[4]采用直接地址索引，iaddr[5]和iaddr[6]采用一级间接地址索引，iaddr[7] 采用二级间接地索引。若用户要访问文件userA中逻辑块号为4和5的信息，则系统应分别采用（），该文件系统可表示的单个文件最大长度是（）KB。</p>","analyze":"<p>每个索引块和磁盘数据块大小为1KB，地址项大小4B，所以一个块可以索引1KB/4B=256个地址。所以：</p><p>直接地址索引范围：0-4，一级间接地址索引范围5-516，二级间接索引的地址范围是517-517+256*256+516=66052。逻辑块号为4和5分别在直接地址范围和一级间接地址范围。由于地址是从0开始，所以单个文件最大长度是66053。<br/></p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930575260536833"],"itemList":[{"id":"794930575243759617","questionId":"794930573373100033","content":"直接地址访问和直接地址访问","answer":0,"chooseValue":"A"},{"id":"794930575260536833","questionId":"794930573373100033","content":"直接地址访问和一级间接地址访问","answer":1,"chooseValue":"B"},{"id":"794930575277314049","questionId":"794930573373100033","content":"一级问接地址访问和一级间接地址访问","answer":0,"chooseValue":"C"},{"id":"794930575294091265","questionId":"794930573373100033","content":"一级间接地址访问和二级间接地址访问","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930518343831553","title":"<p><strong>请作答第<span style=\"color: red\">1</span>空。</strong></p><p>进程P1、P2、P3、P4、P5和P6的前趋图如下所示。用PV操作控制这6个进程之间同步与互斥的程序如下，程序中的空①和空②处应分别为（）， 空③和空④处应分别为（），空⑤和空⑥处应分别为（）。</p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/25d38ab44ec1c8af4c251e6332a68021.png?x-oss-process=style/ruankaodaren\" title=\"25d38ab44ec1c8af4c251e6332a68021.png\" alt=\"image.png\"/><br/><p>begin</p><p> S1，S2，S3，S4，S5，S6：semaphore； //定义信号量</p><p> S1:=0；S2：=0；S3:=0；S4=0；S5:=0；S6:=0；</p><p> Cobegin</p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/b8bc533ea9307201cdc97794652b5b45.png?x-oss-process=style/ruankaodaren\" title=\"b8bc533ea9307201cdc97794652b5b45.png\" alt=\"image.png\"/><p><br/></p> Coend；<br/><p>end.</p>","analyze":"<p>信号量的分配如下图所示。</p><p> <img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/3457a826082f8f010bb724a2e309c194.png?x-oss-process=style/ruankaodaren\" title=\"3457a826082f8f010bb724a2e309c194.png\" alt=\"image.png\"/></p><p>这里进程P1和P6分别是第一个进程和最后一个进程，因此P1只有V操作，信号量是S1，即V（S1）。P6只有P操作，信号量是S5和S6，结果为P（S5）、P（S6），中间进程P2、P3、P4、P5既有P操作也有V操作 ，分别是P2：P（S1）、V（S2）、V（S3），P3：P（S2）、V（S4），P4：P（S3）、V（S5），P5：P（S4）、V（S6）。</p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930520331931649"],"itemList":[{"id":"794930520214491137","questionId":"794930518343831553","content":"V(S1)和PS2)P(S3)","answer":0,"chooseValue":"A"},{"id":"794930520273211393","questionId":"794930518343831553","content":"V(S1)和V(S2)V(S3)","answer":0,"chooseValue":"B"},{"id":"794930520306765825","questionId":"794930518343831553","content":"P(S1)和P(S2)V(S3)","answer":0,"chooseValue":"C"},{"id":"794930520331931649","questionId":"794930518343831553","content":"P(S1)和V(S2)V(S3)","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930484336414721","title":"<p><strong>请作答第<span style=\"color: red\">1</span>空。</strong></p><p>进程P1、P2、P3和P4的前趋图如下所示<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/654def81b9879fc91d9e01d0ad176bb8.png?x-oss-process=style/ruankaodaren\" title=\"654def81b9879fc91d9e01d0ad176bb8.png\" alt=\"image.png\"/><br/></p><p>若用PV操作控制进程P1～P4并发执行的过程，则需要设置5个信号量S1、S2、S3、S4和S5，且信号量S1～S5的初值都等于0。下图中a、b和c处应分别填写（ ）；d、e和f处应分别填写（ ）。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/d77f9dfab3a245590fc25f8c21e3e118.png?x-oss-process=style/ruankaodaren\" title=\"d77f9dfab3a245590fc25f8c21e3e118.png\" alt=\"image.png\"/><br/></p>","analyze":"<p>因为P1是P2和P3的前驱，当P1执行完需通知P2和P3，应采用V(S1)V(S2)操作分别通知P2和P3，故a处应填写V(S1)V(S2)；又因为P2是P1和P3的后继，当P2执行前应测试P1和P3是否执行完，应采用P(S1)P(S4)操作测试P1和P3是否执行完，故b处应填写P(S1)P(S4)；同理，P2是P4的前驱，当P2执行完应通知P4，应采用V(S3)操作分别通知P4，故C处应填写V(S3)。</p><p>因为P3是P1的后继，当P3执行前应测试P1是否执行完，应采用P(S2)操作测试P1是否执行完，故d处应填写P(S2)；又因为P3是P2和P4的前驱，当P3执行完应通知P2和P4，应采用V(S4)V(S5)操作通知P5，故e处应填写V(S4)V(S5)；P4是P2和P3的后继，当P4执行前应测试P2和P3是否执行完，应采用P(S3)P(S5)操作测试P2和P3是否执行完，故f处应填写P(S3)P(S5)。</p>","multi":0,"questionType":1,"answer":"C","chooseItem":["794930486219657217"],"itemList":[{"id":"794930486186102785","questionId":"794930484336414721","content":"V(S1)V(S2)、P(S1)V(S3)和V(S4)","answer":0,"chooseValue":"A"},{"id":"794930486202880001","questionId":"794930484336414721","content":"P(S1)V(S2)、P(S1)P(S2)和V(S1)<br/>","answer":0,"chooseValue":"B"},{"id":"794930486219657217","questionId":"794930484336414721","content":"V(S1)V(S2)、P(S1)P(S3)和V(S4)<br/>","answer":1,"chooseValue":"C"},{"id":"794930486232240129","questionId":"794930484336414721","content":"P(S1)P(S2)、V(S1)P(S3)和V(S2)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930450043785217","title":"<p><strong>请作答第<span style=\"color: red\">1</span>空。</strong></p><p>某数据库中有员工关系E、产品关系P、仓库关系W和库存关系I，其中：员工关系E(employeeID，name，department)中的属性为：员工编号，姓名，部门：产品关系P (productID，name，model，size，color)中的属性为：产品编号，产品名称，型号，尺寸，颜色：仓库关系W(warehouseID，name，address，employeeID.中的属性为：仓库编号，仓库名称，地址，负责人编号；库存关系I(warehouseID，productlD，quantity)中的属性为仓库编号，产品编号和产品数量。</p><p>a．若要求仓库关系的负责人引用员工关系的员工编号，员工关系E的员工编号、仓库关系w的仓库编号和产品关系P的产品编号不能为空且唯一标识一个记录，并且仓库的地址不能为空，则依次要满足的完整性约束是（请作答此空）。</p><p>b．若需得到每种产品的名称和该产品的总库存量，则对应的查询语句为：</p><p> SELELCT name, SUM(quantity)</p><p> FROM P, I</p><p> WHERE （）</p><p> c．若需得到在所有仓库中都存在的产品的名称，则对应的查询语句为：</p><p><br/></p><p> SELECT name FROM P</p><p> WHERE (50) </p><p> (SELECT * FROM W</p><p> WHERE NOT EXISTS</p><p> (SELECT * FROM I</p><p> WHERE P. productID=l.productID AND W. warehouselD=l.warehouseID.)</p>","analyze":"关系模型的完整性规则是对关系的某种约束条件，关系模型中可以有三类完整性约束：实体完整性、参照完整性和用户定义的完整性。实体完整性规定基本关系的主属性不能取空值。由于员工关系E中的员工编号、仓库关系w中的仓库编号和产品关系P中的产品编号都不能为空且唯一标识一个记录，所以应满足实体完整性约束：参照完整性规定实体间引用的完整性，本表中外码的值必须取空值或者在被引用的表中存在的相对应的主码值。由于仓库关系的负责人引用了员工关系的员工编号，所以应满足参照完整性约束；实体完整性和参照完整性是所有数据库系统都要支持的完整性约束。而用户定义的完整性是针对某一具体关系数据库的约束条件，它反映某一具体应用所涉及的数据必须满足的语义要求。根据题目要求：仓库的地址不能为空，所以也应满足用户定义完整性约束。从上述完整性说明来看，正确答案应为A。","multi":0,"questionType":1,"answer":"A","chooseItem":["794930451906056193"],"itemList":[{"id":"794930451906056193","questionId":"794930450043785217","content":"实体完整性、参照完整性、用户定义完整性","answer":1,"chooseValue":"A"},{"id":"794930451922833409","questionId":"794930450043785217","content":"参照完整性、实体完整性、用户定义完整性","answer":0,"chooseValue":"B"},{"id":"794930451939610625","questionId":"794930450043785217","content":"用户定义完整性、实体完整性、参照完整性","answer":0,"chooseValue":"C"},{"id":"794930451956387841","questionId":"794930450043785217","content":"实体完整性、用户定义完整性、参照完整性","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930470046420993","title":"<p><strong>请作答第<span style=\"color: red\">1</span>空。</strong></p><p>某文件系统采用索引节点管理，其磁盘索引块和磁盘数据块大小均为1KB字节且每个文件索引节点有8个地址项iaddr[0]～iaddr[7]，每个地址项大小为4字节，其中iaddr[0]～iaddr[4]采用直接地址索引，iaddr[5]和iaddr[6]采用一级间接地址索引，iaddr[7] 采用二级间接地址索引。若用户要访问文件userA中逻辑块号为4和5的信息，则系统应分别采用（5），该文件系统可表示的单个文件最大长度是（6）KB。</p>","analyze":"<p>每个索引块和磁盘数据块大小为1KB，地址项大小4B，所以一个块可以索引1KB/4B=256个地址。所以：</p><p>直接地址索引范围：0-4，一级间接地址索引范围5-516，二级间接索引的地址范围是517-517+256*256+516=66052。逻辑块号为4和5分别在直接地址范围和一级间接地址范围。由于地址是从0开始，所以单个文件最大长度是66053。</p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930471917080577"],"itemList":[{"id":"794930471896109057","questionId":"794930470046420993","content":"直接地址访问和直接地址访问","answer":0,"chooseValue":"A"},{"id":"794930471917080577","questionId":"794930470046420993","content":"直接地址访问和一级间接地址访问","answer":1,"chooseValue":"B"},{"id":"794930471933857793","questionId":"794930470046420993","content":"一级间接地址访问和一级间接地址访问","answer":0,"chooseValue":"C"},{"id":"794930471950635009","questionId":"794930470046420993","content":"一级间接地址访问和二级间接地址访问","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930541332811777","title":"<p><strong>请作答第<span style=\"color: red\">1</span>空。</strong></p><p>进程P1、P2、P3、P4和P5的前趋图如下图所示：</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/441039c80db53045b3b7ac5808fe4ed6.jpg?x-oss-process=style/ruankaodaren\" title=\"441039c80db53045b3b7ac5808fe4ed6.jpg\" alt=\"111.jpg\" width=\"242\" height=\"116\"/></p><p>若用PV操作控制这5个进程的同步与互斥的程序如下，那么程序中的空①和空②处应分别为 （2） ；空③和空④处应分别为 （3） ；空⑤和空⑥处应分别为 （4） 。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/389d6a23e71945c690c0019c301e0946.png?x-oss-process=style/ruankaodaren\" title=\"389d6a23e71945c690c0019c301e0946.png\" alt=\"image.png\" width=\"206\" height=\"188\"/></p>","analyze":"<p>PV操作中的P，是荷兰语Passeren的缩写，意为“通过（pass）”；V是荷兰语vrijgeven的缩写，意为“释放（give）”。</p><p>根据前驱图，进程P1执行完毕后需要利用V（S1）、V（S2）通知进程P2、P3，所以①填V（S2）。</p><p>进程P2中，需要利用P（S1）判断前驱进程P1是否运行完毕。因此②填P（S1）。进程P2执行完毕后需要利用V（S3）、V（S4）、V（S5）通知进程P3、P4、P5。</p><p>进程P3中，需要利用P（S2）、P（S3）判断前驱进程P1、P2是否运行完毕，所以③填P（S3）。进程P3执行完毕后需要利用V（S6）通知进程P5，所以④填V（S6）。</p><p>进程P4中，需要利用P（S4）判断前驱进程P2是否运行完毕。进程P4执行完毕后需要利用V（S7）通知进程P5，所以⑤填P（S4）。</p><p>进程P5中，需要利用P（S5）、P（S6）、P（S7）判断前驱进程P2、P3、P4是否运行完毕，所以⑥填P（S6）P（S7）。</p><p>将前驱图标明信号，如下图所示，可以更直观的解题。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/0d4d592bf37c56c5b38e0a80c08f8069.jpg?x-oss-process=style/ruankaodaren\" title=\"0d4d592bf37c56c5b38e0a80c08f8069.jpg\" alt=\"111.jpg\"/></p><br/>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930543593541633"],"itemList":[{"id":"794930543551598593","questionId":"794930541332811777","content":"V（S1）和P（S2）","answer":0,"chooseValue":"A"},{"id":"794930543564181505","questionId":"794930541332811777","content":"P（S1）和V（S2）","answer":0,"chooseValue":"B"},{"id":"794930543576764417","questionId":"794930541332811777","content":"V（S1）和V（S2）","answer":0,"chooseValue":"C"},{"id":"794930543593541633","questionId":"794930541332811777","content":"V（S2）和P（S1）","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930507006627841","title":"<p><strong>请作答第<span style=\"color: red\">1</span>空。</strong></p><p>若某分页管理的虚拟存储器共有8个页面，每页为1024个字节，实际主存为 4096 个字节，采用页表法进行地址映像。若页表的内容如下表所示，则发生页面失效的全部虚页号为（ ），虚拟地址1023所对应的主存实地址页内偏移地址为（ ），主存实地址为（ ）。</p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/ddecbd414bb1380bae73df6cd736b447.jpg?x-oss-process=style/ruankaodaren\" title=\"ddecbd414bb1380bae73df6cd736b447.jpg\" alt=\"1.jpg\"/>","analyze":"在页表中已经列出未装入的虚页号分别是2、3、5、7，也就是说这些页面不在主存中。现已给出虚拟地址为1023，其虚页号应为∶虚地址/页面大小，那1023/1024=0，故其虚页号应为 0。页内编移量等于虚地址-（虚页号×页面大小），即 1023-0=1023。实存地址为∶实页号×页面大小+页内编移地址，查表可以看到它所对应的实页号为3，即3×1024+1023=4095，得到实存地址为4095。","multi":0,"questionType":1,"answer":"A","chooseItem":["794930508864704513"],"itemList":[{"id":"794930508864704513","questionId":"794930507006627841","content":"2、3、5、7","answer":1,"chooseValue":"A"},{"id":"794930508889870337","questionId":"794930507006627841","content":"0、1、4、6","answer":0,"chooseValue":"B"},{"id":"794930508915036161","questionId":"794930507006627841","content":"1、5、6、7","answer":0,"chooseValue":"C"},{"id":"794930508940201985","questionId":"794930507006627841","content":"0、2、3、4","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930590678798337","title":"<p><strong>请作答第<span style=\"color: red\">1</span>空。</strong></p>在进程资源有向图中，圆圈表示进程，方框表示资源，方框内的小圆数表示资源数。当有向边（或称请求边）由进程指向资源时，表示申请一个资源；当有向边（或称分配边）由资源指向进程时，表示获得一个资源。假设系统中有三个进程Pl、P2和P3，两种资源R1、 R2，且R1的资源数等于3，R2的资源数等于3。如果进程资源图如图（a）和图（b）所示，那么图（a）中 （5） ；图（b）中 （6） 。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/d848624a6fba06d4b3467ea0f582f9dc.png?x-oss-process=style/ruankaodaren\" title=\"d848624a6fba06d4b3467ea0f582f9dc.png\" alt=\"image.png\"/>","analyze":"<p>（1）R表示资源，P表示进程，方框的小圆圈表示资源数。</p><p>（2）R→P（R指向P）：表示分配一个资源R给进程P；P→R（P指向R）：表示进程P申请一个资源R。</p><p>（3）阻塞节点：当R资源分配完毕，此时还有进程P向R申请资源，则该进程P成为阻塞节点。</p><p>（4）非阻塞节点：进程P向R申请资源，此时R还有资源分配，则该进程P成为非阻塞节点。</p><p>（5）不可化简：图中所有节点都是阻塞节点。</p><p>（6）可化简：将非阻塞节点周围的箭头删去，只保留阻塞节点的箭头。如果新图中，原阻塞节点变为非阻塞节点，则可以化简。</p><p>分析图（a），进程P1、P2、P3总共分配2个R1资源，申请1个R1资源，显然R1资源够用；进程P1、P2、P3各分配1个R2资源，R2资源分配完毕，但此时各自还需要申请1个R2。显然，P1、P2、P3都是阻塞节点，因此该图不可以化简，是死锁的。</p><p>分析图（b），P1、P2、P3各分配1个R2资源，但P1还需要申请1个R2无法得到满足因此P1是阻塞节点。P1、P2各分配1个R1资源，但P2还需要申请2个R1无法得到满足，因此P2是阻塞节点。P3节点不需要申请资源，因此是非阻塞节点。当进程P3运行完毕，可以释放获得的R1、R2资源。此时，P2可以由阻塞节点变为非阻塞节点，因此该图是可以化简的。</p><p>参考答案：（5）A；（6）C</p>","multi":0,"questionType":1,"answer":"A","chooseItem":["794930592532680705"],"itemList":[{"id":"794930592532680705","questionId":"794930590678798337","content":"P1、P2、P3都是阻塞节点，该图不可以化简，是死锁的","answer":1,"chooseValue":"A"},{"id":"794930592553652225","questionId":"794930590678798337","content":"P1、P2、P3都是非阻塞节点，该图可以化简，是非死锁的","answer":0,"chooseValue":"B"},{"id":"794930592574623745","questionId":"794930590678798337","content":"P1、P2是非阻塞节点，P3是阻塞节点，该图不可以化简，是死锁的","answer":0,"chooseValue":"C"},{"id":"794930592591400961","questionId":"794930590678798337","content":"P3是非阻塞节点，P1、P3是阻塞节点，该图可以化简，是非死锁的","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930584857104385","title":"<p><strong>请作答第<span style=\"color: red\">1</span>空。</strong></p><p>前驱图是一个有向无环图，记为→={（Pi，Pj），Pi完成时间先于P j开始时间}。假设系统中进程P={P1，P2，P3，P4，P5，P6，P7，P 8}，且进程的前驱图如下。那么该前驱图可记为 （3） ，图中 （4） 。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/fea264bbce541d9ee8ccbbc2675f111a.png?x-oss-process=style/ruankaodaren\" title=\"fea264bbce541d9ee8ccbbc2675f111a.png\" alt=\"image.png\"/></p>","analyze":"前趋图是一个有向无环图，用于描述进程之间执行的顺序关系。前趋图结点表示进程、程序段，有向边表示节点之间的前驱关系。<p>前趋图中结点间的前驱关系图中用“→”表示，因此，本题有前驱关系的十个结点对，分别是（P1，P2），（P1，P4），（P2，P3），（P2，P5），（P3，P4），（P3，P6），（P4，P7），（P5，P6），（P6，P8），（p7，p6）。</p><p>有向无环图根据箭头方向判断是否存在环路，本题图中不存在环路。</p><p>前趋图显示的是进程之间的同步关系，与互斥无关。</p><p>P2、P3、P4之间存在依赖关系，所以P2比P4先执行完成；P5与P7之间不存在依赖关系，所以不能判断其先后关系。</p><p>参考答案：（3）B；（4）D</p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930586782289921"],"itemList":[{"id":"794930586761318401","questionId":"794930584857104385","content":"→={（P1，P2），（P1，P3），（P1，P4），（P2，P5），（P3，P2），（P3，P4），（P3，P6），（P4，P7），（P5，P8）","answer":0,"chooseValue":"A"},{"id":"794930586782289921","questionId":"794930584857104385","content":"→={（P1，P2），（P1，P4），（P2，P3），（P2，P5），（P3，P4），（P3，P6），（P4，P7），（P5，P6），（P6，P8），（p7，p6）}","answer":1,"chooseValue":"B"},{"id":"794930586803261441","questionId":"794930584857104385","content":"→={（P1，P2），（P1，P4），（P2，P5），（P3，P2），（P3，P4），（P3，P6），（P4，P6），（P4，P7），（P6，P8），（p7，p8）}","answer":0,"chooseValue":"C"},{"id":"794930586832621569","questionId":"794930584857104385","content":"→={（P1，P2），（P1，P3），（P2，P4），（P2，P5），（P3，P2），（P3，P4），（P3，P5），（P4，P7），（P6，P8），（p7，p8）}","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930559154409473","title":"<p><strong>请作答第<span style=\"color: red\">1</span>空。</strong></p><p>进程P1、P2、P3、P4、P5和P6的前趋图如下所示。用PV操作控制这6个进程之间同步与互斥的程序如下，程序中的空①和空②处应分别为（）， 空③和空④处应分别为（），空⑤和空⑥处应分别为（）。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/80140d24578af1c13bef5bcdcbe6c25b.png?x-oss-process=style/ruankaodaren\" title=\"80140d24578af1c13bef5bcdcbe6c25b.png\" alt=\"image.png\"/><br/></p><p>begin</p><p> S1，S2，S3，S4，S5，S6：semaphore； //定义信号量</p><p> S1:=0；S2：=0；S3:=0；S4=0；S5:=0；S6:=0；</p><p> Cobegin</p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/81d12d46ca708e06e3f83ccc06dcd12b.png?x-oss-process=style/ruankaodaren\" title=\"81d12d46ca708e06e3f83ccc06dcd12b.png\" alt=\"image.png\"/><br/><p> Coend；</p><p>end.</p>","analyze":"信号量的分配如下图所示。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/58799487a5e192951709b12ceee723c6.png?x-oss-process=style/ruankaodaren\" title=\"58799487a5e192951709b12ceee723c6.png\" alt=\"image.png\"/><br/><p>这里进程P1和P6分别是第一个进程和最后一个进程，因此P1只有V操作，信号量是S2，即V（S2）。P6只有P操作，信号量是S5和S6，结果为P（S5）、P（S6），中间进程P2、P3、P4、P5既有P操作也有V操作 ，分别是P2：P（S1）、V（S2）、V（S3），P3：P（S2）、V（S4），P4：P（S3）、V（S5），P5：P（S4）、V（S6）。</p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930561117343745"],"itemList":[{"id":"794930561041846273","questionId":"794930559154409473","content":"V(S1)和PS2)P(S3）","answer":0,"chooseValue":"A"},{"id":"794930561067012097","questionId":"794930559154409473","content":"V(S1)和V(S2)V(S3)","answer":0,"chooseValue":"B"},{"id":"794930561092177921","questionId":"794930559154409473","content":"P(S1)和P(S2)V(S3)","answer":0,"chooseValue":"C"},{"id":"794930561117343745","questionId":"794930559154409473","content":"P(S1)和V(S2)V(S3)","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930531392311297","title":"<p><strong>请作答第<span style=\"color: red\">1</span>空。</strong></p><p>某文件系统采用索引节点管理，其磁盘索引块和磁盘数据块大小均为1KB字节且每个文件索引节点有8个地址项iaddr[0]～iaddr[7]，每个地址项大小为4字节，其中iaddr[0]～iaddr[4]采用直接地址索引，iaddr[5]和iaddr[6]采用一级间接地址索引，iaddr[7] 采用二级间接地址索引。若用户要访问文件userA中逻辑块号为4和5的信息，则系统应分别采用（），该文件系统可表示的单个文件最大长度是（）KB。</p>","analyze":"<p>每个索引块和磁盘数据块大小为1KB，地址项大小4B，所以一个块可以索引1KB/4B=256个地址。所以：</p><p>直接地址索引范围：0-4，一级间接地址索引范围5-516，二级间接索引的地址范围是517-517+256*256+516=66052。逻辑块号为4和5分别在直接地址范围和一级间接地址范围。由于地址是从0开始，所以单个文件最大长度是66053。</p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930533611098113"],"itemList":[{"id":"794930533594320897","questionId":"794930531392311297","content":"直接地址访问和直接地址访问","answer":0,"chooseValue":"A"},{"id":"794930533611098113","questionId":"794930531392311297","content":"直接地址访问和一级间接地址访问","answer":1,"chooseValue":"B"},{"id":"794930533627875329","questionId":"794930531392311297","content":"一级问接地址访问和一级间接地址访问","answer":0,"chooseValue":"C"},{"id":"794930533644652545","questionId":"794930531392311297","content":"一级间接地址访问和二级间接地址访问","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930458713411585","title":"<p><strong>请作答第<span style=\"color: red\">1</span>空。</strong></p><p>微内核的操作系统(OS)结构如图所示，图中①和②分别工作在 （ ）方式下，与传统的OS结构模式相比，采用微内核的OS结构模式的优点是提高了系统的灵活性、可扩充性，（ ）。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/a425045e0594ee1649c6efe9155ec3db.jpg?x-oss-process=style/ruankaodaren\" title=\"a425045e0594ee1649c6efe9155ec3db.jpg\" alt=\"系分4444444444444444444444.jpg\"/></p>","analyze":"<p>现代操作系统大多拥有两种工作状态：核心态和用户态。我们使用的一般应用程序工作在用户态，而内核模块和最基本的操作系统核心工作在核心态。</p><p>微内核结构由一个非常简单的硬件抽象层和一组比较关键的原语或系统调用组成，这些原语仅仅包括了建立一个系统必需的几个部分，如线程管理，地址空间和进程间通信等。微内核的目标是将系统服务的实现和系统的基本操作规则分离开来。例如，进程的输入/输出锁定服务可以由运行在微内核之外的一个服务组件来提供。这些非常模块化的用户态服务用于完成操作系统中比较高级的操作，这样的设计使内核中最核心的部分的设计更简单。一个服务组件的失效并不会导致整个系统的崩溃，内核需要做的，仅仅是重新启动这个组件，而不必影响其他的部分。</p><p>微内核技术的主要优点如下：</p><p>统一的接口，在用户态和核心态之间无须进程识别。</p><p>可伸缩性好，能适应硬件更新和应用变化。</p><p>可移植性好，所有与具体机器特征相关的代码，全部隔离在微内核中，如果操作系统要移植到不同的硬件平台上，只需修改微内核中极少代码即可。</p><p>实时性好，微内核可以方便地支持实时处理。</p><p>安全可靠性高，微内核将安全性作为系统内部特性来进行设计，对外仅使用少量应用编程接口。</p><p>支持分布式系统，支持多处理器的体系结构和高度并行的应用程序。</p><p>真正面向对象的操作系统。</p><p>由于操作系统核心常驻内存，而微内核结构精简了操作系统的核心功能，内核规模比较小，一些功能都移到了外存上，所以微内核结构十分适合嵌入式的专用系统，对于通用性较广的系统，将使CPU的通信开销增大，从而影响到计算机的运行速度。</p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930460621819905"],"itemList":[{"id":"794930460605042689","questionId":"794930458713411585","content":"核心态和用户态","answer":0,"chooseValue":"A"},{"id":"794930460621819905","questionId":"794930458713411585","content":"用户态和核心态","answer":1,"chooseValue":"B"},{"id":"794930460642791425","questionId":"794930458713411585","content":"用户态和用户态","answer":0,"chooseValue":"C"},{"id":"794930460659568641","questionId":"794930458713411585","content":"核心态和核心态","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930579140268033","title":"<p><strong>请作答第<span style=\"color: red\">1</span>空。</strong></p>在一个单CPU的计算机系统中，采用可剥夺式（也称抢占式）优先级的进程调度方案，且所有任务可以并行使用I/O设备。下表列出了三个任务T1、T2、T3的优先级、独立运行时占用CPU和I/O设备的时间。如果操作系统的开销忽略不计，这三个任务从同时启动到全部结束的总时间为 （1） ms，CPU的繁忙时间共有 （2） ms。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/2705a85a2c98c5bae1a0a9b44ad2859d.png?x-oss-process=style/ruankaodaren\" title=\"2705a85a2c98c5bae1a0a9b44ad2859d.png\" alt=\"image.png\"/>","analyze":"<p>时间分析如下图所示。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/b38672af03f38866a3e4874c6abe3ff7.png?x-oss-process=style/ruankaodaren\" title=\"b38672af03f38866a3e4874c6abe3ff7.png\" alt=\"image.png\"/><br/>由图可知，第1题应该是87ms。</p><p>CPU的空闲时间是18ms，繁忙时间是87-18=69ms。</p><p>参考答案：（1）C；（2）D</p><p><br/></p><br/>","multi":0,"questionType":1,"answer":"C","chooseItem":["794930581019316225"],"itemList":[{"id":"794930580989956097","questionId":"794930579140268033","content":"41","answer":0,"chooseValue":"A"},{"id":"794930581002539009","questionId":"794930579140268033","content":"71","answer":0,"chooseValue":"B"},{"id":"794930581019316225","questionId":"794930579140268033","content":"87","answer":1,"chooseValue":"C"},{"id":"794930581031899137","questionId":"794930579140268033","content":"123","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930421686095873","title":"<p><strong>请作答第<span style=\"color: red\">1</span>空。</strong></p><p>进程P1、P2、P3、P4、P5和P6的前趋图如下所示：</p><p><br/></p><p>若用PV操作控制这6个进程的同步与互斥的程序如下，那么程序中的空a、空b和空c处应分别为（1）；空d和空e处应分别为（2）；空f和空g处应分别为（3）。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/1ca45bb5217f7013a881f17c5ac96727.jpg?x-oss-process=style/ruankaodaren\" title=\"1ca45bb5217f7013a881f17c5ac96727.jpg\" alt=\"1.jpg\"/></p><p>begin</p><p> S1，S2，S3，S4，S5，S6，S7：semaphore； //定义信号量</p><p> S1:=0；S2：=0；S3:=0；S4=0；S5:=0；S6:=0；S7:=0；</p><p> Cobegin</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/2633837fb39cb8b482009769c69d9053.jpg?x-oss-process=style/ruankaodaren\" title=\"2633837fb39cb8b482009769c69d9053.jpg\" alt=\"2.jpg\"/> Coend；</p><p>end</p>","analyze":"P2进程需要等待P1进程的通知，需要进行P (S1) 操作测试P1进程是否运行完，P2进程运行结束需要进行V操作分别通知P4进程，所以空a应填V (S2)用以通知P4进程可以执行；前驱图P3进程开始运行前必须等待P1 进程的通知，需要用P操作测试P1进程是否运行完，所以空b应填P (S2)操作测试P1进程是否运行完；P3进程运行结束需要利用V (S4) V (S5)操作通知P4和P5进程可以开始运行，故空c应填V (S4) V (S5)。","multi":0,"questionType":1,"answer":"A","chooseItem":["794930423636447233"],"itemList":[{"id":"794930423636447233","questionId":"794930421686095873","content":"V(S3)、P(S2)和V(S4)V(S5）","answer":1,"chooseValue":"A"},{"id":"794930423653224449","questionId":"794930421686095873","content":"P(S3)、P(S2)和V(S4)V(S5)","answer":0,"chooseValue":"B"},{"id":"794930423670001665","questionId":"794930421686095873","content":"V(S2)、P(S3)和P(S4)P(S3）","answer":0,"chooseValue":"C"},{"id":"794930423686778881","questionId":"794930421686095873","content":"V(S2)、V(S3)和P(S3)P(S4)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930461569732609","title":"<p><strong>请作答第<span style=\"color: red\">2</span>空。</strong></p><p>微内核的操作系统(OS)结构如图所示，图中①和②分别工作在 （ ）方式下，与传统的OS结构模式相比，采用微内核的OS结构模式的优点是提高了系统的灵活性、可扩充性，（ ）。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/a425045e0594ee1649c6efe9155ec3db.jpg?x-oss-process=style/ruankaodaren\" title=\"a425045e0594ee1649c6efe9155ec3db.jpg\" alt=\"系分4444444444444444444444.jpg\"/></p>","analyze":"<p>现代操作系统大多拥有两种工作状态：核心态和用户态。我们使用的一般应用程序工作在用户态，而内核模块和最基本的操作系统核心工作在核心态。</p><p>微内核结构由一个非常简单的硬件抽象层和一组比较关键的原语或系统调用组成，这些原语仅仅包括了建立一个系统必需的几个部分，如线程管理，地址空间和进程间通信等。微内核的目标是将系统服务的实现和系统的基本操作规则分离开来。例如，进程的输入/输出锁定服务可以由运行在微内核之外的一个服务组件来提供。这些非常模块化的用户态服务用于完成操作系统中比较高级的操作，这样的设计使内核中最核心的部分的设计更简单。一个服务组件的失效并不会导致整个系统的崩溃，内核需要做的，仅仅是重新启动这个组件，而不必影响其他的部分。</p><p>微内核技术的主要优点如下：</p><p>统一的接口，在用户态和核心态之间无须进程识别。</p><p>可伸缩性好，能适应硬件更新和应用变化。</p><p>可移植性好，所有与具体机器特征相关的代码，全部隔离在微内核中，如果操作系统要移植到不同的硬件平台上，只需修改微内核中极少代码即可。</p><p>实时性好，微内核可以方便地支持实时处理。</p><p>安全可靠性高，微内核将安全性作为系统内部特性来进行设计，对外仅使用少量应用编程接口。</p><p>支持分布式系统，支持多处理器的体系结构和高度并行的应用程序。</p><p>真正面向对象的操作系统。</p><p>由于操作系统核心常驻内存，而微内核结构精简了操作系统的核心功能，内核规模比较小，一些功能都移到了外存上，所以微内核结构十分适合嵌入式的专用系统，对于通用性较广的系统，将使CPU的通信开销增大，从而影响到计算机的运行速度。</p>","multi":0,"questionType":1,"answer":"A","chooseItem":["794930463436197889"],"itemList":[{"id":"794930463436197889","questionId":"794930461569732609","content":"并增强了可靠性，可运行于分布式系统中","answer":1,"chooseValue":"A"},{"id":"794930463452975105","questionId":"794930461569732609","content":"并增强了可靠性，但不适用于分布式系统","answer":0,"chooseValue":"B"},{"id":"794930463465558017","questionId":"794930461569732609","content":"但降低了可靠性，可运行于分布式系统中","answer":0,"chooseValue":"C"},{"id":"794930463482335233","questionId":"794930461569732609","content":"但降低了可靠性，不适用于分布式系统","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930593505759233","title":"<p><strong>请作答第<span style=\"color: red\">2</span>空。</strong></p>在进程资源有向图中，圆圈表示进程，方框表示资源，方框内的小圆数表示资源数。当有向边（或称请求边）由进程指向资源时，表示申请一个资源；当有向边（或称分配边）由资源指向进程时，表示获得一个资源。假设系统中有三个进程Pl、P2和P3，两种资源R1、 R2，且R1的资源数等于3，R2的资源数等于3。如果进程资源图如图（a）和图（b）所示，那么图（a）中 （5） ；图（b）中 （6） 。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/d848624a6fba06d4b3467ea0f582f9dc.png?x-oss-process=style/ruankaodaren\" title=\"d848624a6fba06d4b3467ea0f582f9dc.png\" alt=\"image.png\"/>","analyze":"<p>（1）R表示资源，P表示进程，方框的小圆圈表示资源数。</p><p>（2）R→P（R指向P）：表示分配一个资源R给进程P；P→R（P指向R）：表示进程P申请一个资源R。</p><p>（3）阻塞节点：当R资源分配完毕，此时还有进程P向R申请资源，则该进程P成为阻塞节点。</p><p>（4）非阻塞节点：进程P向R申请资源，此时R还有资源分配，则该进程P成为非阻塞节点。</p><p>（5）不可化简：图中所有节点都是阻塞节点。</p><p>（6）可化简：将非阻塞节点周围的箭头删去，只保留阻塞节点的箭头。如果新图中，原阻塞节点变为非阻塞节点，则可以化简。</p><p>分析图（a），进程P1、P2、P3总共分配2个R1资源，申请1个R1资源，显然R1资源够用；进程P1、P2、P3各分配1个R2资源，R2资源分配完毕，但此时各自还需要申请1个R2。显然，P1、P2、P3都是阻塞节点，因此该图不可以化简，是死锁的。</p><p>分析图（b），P1、P2、P3各分配1个R2资源，但P1还需要申请1个R2无法得到满足因此P1是阻塞节点。P1、P2各分配1个R1资源，但P2还需要申请2个R1无法得到满足，因此P2是阻塞节点。P3节点不需要申请资源，因此是非阻塞节点。当进程P3运行完毕，可以释放获得的R1、R2资源。此时，P2可以由阻塞节点变为非阻塞节点，因此该图是可以化简的。</p><p>参考答案：（5）A；（6）C</p>","multi":0,"questionType":1,"answer":"C","chooseItem":["794930595397390337"],"itemList":[{"id":"794930595355447297","questionId":"794930593505759233","content":"P1、P2、P3都是非阻塞节点，该图可以化简，是非死锁的","answer":0,"chooseValue":"A"},{"id":"794930595376418817","questionId":"794930593505759233","content":"P1、P2、P3都是阻塞节点，该图不可以化简，是死锁的","answer":0,"chooseValue":"B"},{"id":"794930595397390337","questionId":"794930593505759233","content":"P3是非阻塞节点，P1、P2是阻塞节点，该图可以化简，是非死锁的","answer":1,"chooseValue":"C"},{"id":"794930595422556161","questionId":"794930593505759233","content":"P1、P2是非阻塞节点，P3是阻塞节点，该图不可以化简，是死锁的","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930534705811457","title":"<p><strong>请作答第<span style=\"color: red\">2</span>空。</strong></p><p>某文件系统采用索引节点管理，其磁盘索引块和磁盘数据块大小均为1KB字节且每个文件索引节点有8个地址项iaddr[0]～iaddr[7]，每个地址项大小为4字节，其中iaddr[0]～iaddr[4]采用直接地址索引，iaddr[5]和iaddr[6]采用一级间接地址索引，iaddr[7] 采用二级间接地址索引。若用户要访问文件userA中逻辑块号为4和5的信息，则系统应分别采用（），该文件系统可表示的单个文件最大长度是（）KB。</p>","analyze":"<p>每个索引块和磁盘数据块大小为1KB，地址项大小4B，所以一个块可以索引1KB/4B=256个地址。所以：</p><p>直接地址索引范围：0-4，一级间接地址索引范围5-516，二级间接索引的地址范围是517-517+256*256+516=66052。逻辑块号为4和5分别在直接地址范围和一级间接地址范围。由于地址是从0开始，所以单个文件最大长度是66053。</p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930536953958401"],"itemList":[{"id":"794930536903626753","questionId":"794930534705811457","content":"517","answer":0,"chooseValue":"A"},{"id":"794930536920403969","questionId":"794930534705811457","content":"1029","answer":0,"chooseValue":"B"},{"id":"794930536937181185","questionId":"794930534705811457","content":"65797","answer":0,"chooseValue":"C"},{"id":"794930536953958401","questionId":"794930534705811457","content":"66053","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930581950451713","title":"<p><strong>请作答第<span style=\"color: red\">2</span>空。</strong></p>在一个单CPU的计算机系统中，采用可剥夺式（也称抢占式）优先级的进程调度方案，且所有任务可以并行使用I/O设备。下表列出了三个任务T1、T2、T3的优先级、独立运行时占用CPU和I/O设备的时间。如果操作系统的开销忽略不计，这三个任务从同时启动到全部结束的总时间为 （1） ms，CPU的繁忙时间共有 （2） ms。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/2705a85a2c98c5bae1a0a9b44ad2859d.png?x-oss-process=style/ruankaodaren\" title=\"2705a85a2c98c5bae1a0a9b44ad2859d.png\" alt=\"image.png\"/>","analyze":"<p>时间分析如下图所示。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/b38672af03f38866a3e4874c6abe3ff7.png?x-oss-process=style/ruankaodaren\" title=\"b38672af03f38866a3e4874c6abe3ff7.png\" alt=\"image.png\"/><br/>由图可知，第1题应该是87ms。</p><p>CPU的空闲时间是18ms，繁忙时间是87-18=69ms。</p><p>参考答案：（1）C；（2）D</p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930583900803073"],"itemList":[{"id":"794930583829499905","questionId":"794930581950451713","content":"15","answer":0,"chooseValue":"A"},{"id":"794930583854665729","questionId":"794930581950451713","content":"18","answer":0,"chooseValue":"B"},{"id":"794930583879831553","questionId":"794930581950451713","content":"58","answer":0,"chooseValue":"C"},{"id":"794930583900803073","questionId":"794930581950451713","content":"69","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930587755368449","title":"<p><strong>请作答第<span style=\"color: red\">2</span>空。</strong></p><p>前驱图是一个有向无环图，记为→={（Pi，Pj），Pi完成时间先于P j开始时间}。假设系统中进程P={P1，P2，P3，P4，P5，P6，P7，P 8}，且进程的前驱图如下。那么该前驱图可记为 （3） ，图中 （4） 。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/fea264bbce541d9ee8ccbbc2675f111a.png?x-oss-process=style/ruankaodaren\" title=\"fea264bbce541d9ee8ccbbc2675f111a.png\" alt=\"image.png\"/></p>","analyze":"<p>前趋图是一个有向无环图，用于描述进程之间执行的顺序关系。前趋图结点表示进程、程序段，有向边表示节点之间的前驱关系。</p><p>前趋图中结点间的前驱关系图中用“→”表示，因此，本题有前驱关系的十个结点对，分别是（P1，P2），（P1，P4），（P2，P3），（P2，P5），（P3，P4），（P3，P6），（P4，P7），（P5，P6），（P6，P8），（p7，p6）。</p><p>有向无环图根据箭头方向判断是否存在环路，本题图中不存在环路。</p><p>前趋图显示的是进程之间的同步关系，与互斥无关。</p><p>P2、P3、P4之间存在依赖关系，所以P2比P4先执行完成；P5与P7之间不存在依赖关系，所以不能判断其先后关系。</p><p>参考答案：（3）B；（4）D</p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930589764440065"],"itemList":[{"id":"794930589672165377","questionId":"794930587755368449","content":"图中存在环路，所以本图有误。","answer":0,"chooseValue":"A"},{"id":"794930589705719809","questionId":"794930587755368449","content":"P3、P5、P7都指向P6，它们之间存在互斥关系。","answer":0,"chooseValue":"B"},{"id":"794930589735079937","questionId":"794930587755368449","content":"P5一定比P7先执行完成。","answer":0,"chooseValue":"C"},{"id":"794930589764440065","questionId":"794930587755368449","content":"P2一定比P4先执行完成。","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930544839249921","title":"<p><strong>请作答第<span style=\"color: red\">2</span>空。</strong></p><p>进程P1、P2、P3、P4和P5的前趋图如下图所示：</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/441039c80db53045b3b7ac5808fe4ed6.jpg?x-oss-process=style/ruankaodaren\" title=\"441039c80db53045b3b7ac5808fe4ed6.jpg\" alt=\"111.jpg\" width=\"242\" height=\"116\"/></p><p>若用PV操作控制这5个进程的同步与互斥的程序如下，那么程序中的空①和空②处应分别为 （2） ；空③和空④处应分别为 （3） ；空⑤和空⑥处应分别为 （4） 。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/389d6a23e71945c690c0019c301e0946.png?x-oss-process=style/ruankaodaren\" title=\"389d6a23e71945c690c0019c301e0946.png\" alt=\"image.png\" width=\"206\" height=\"188\"/></p>","analyze":"<p>PV操作中的P，是荷兰语Passeren的缩写，意为“通过（pass）”；V是荷兰语vrijgeven的缩写，意为“释放（give）”。</p><p>根据前驱图，进程P1执行完毕后需要利用V（S1）、V（S2）通知进程P2、P3，所以①填V（S2）。</p><p>进程P2中，需要利用P（S1）判断前驱进程P1是否运行完毕。因此②填P（S1）。进程P2执行完毕后需要利用V（S3）、V（S4）、V（S5）通知进程P3、P4、P5。</p><p>进程P3中，需要利用P（S2）、P（S3）判断前驱进程P1、P2是否运行完毕，所以③填P（S3）。进程P3执行完毕后需要利用V（S6）通知进程P5，所以④填V（S6）。</p><p>进程P4中，需要利用P（S4）判断前驱进程P2是否运行完毕。进程P4执行完毕后需要利用V（S7）通知进程P5，所以⑤填P（S4）。</p><p>进程P5中，需要利用P（S5）、P（S6）、P（S7）判断前驱进程P2、P3、P4是否运行完毕，所以⑥填P（S6）P（S7）。</p><p>将前驱图标明信号，如下图所示，可以更直观的解题。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/0d4d592bf37c56c5b38e0a80c08f8069.jpg?x-oss-process=style/ruankaodaren\" title=\"0d4d592bf37c56c5b38e0a80c08f8069.jpg\" alt=\"111.jpg\"/></p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930546722492417"],"itemList":[{"id":"794930546709909505","questionId":"794930544839249921","content":"V（S4）和V（S5）","answer":0,"chooseValue":"A"},{"id":"794930546722492417","questionId":"794930544839249921","content":"P（S3）和V（S6）","answer":1,"chooseValue":"B"},{"id":"794930546739269633","questionId":"794930544839249921","content":"V（S3）和V（S4）","answer":0,"chooseValue":"C"},{"id":"794930546756046849","questionId":"794930544839249921","content":"P（S4）和P（S3）","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930562035896321","title":"<p><strong>请作答第<span style=\"color: red\">2</span>空。</strong></p><p>进程P1、P2、P3、P4、P5和P6的前趋图如下所示。用PV操作控制这6个进程之间同步与互斥的程序如下，程序中的空①和空②处应分别为（）， 空③和空④处应分别为（），空⑤和空⑥处应分别为（）。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/80140d24578af1c13bef5bcdcbe6c25b.png?x-oss-process=style/ruankaodaren\" title=\"80140d24578af1c13bef5bcdcbe6c25b.png\" alt=\"image.png\"/><br/></p><p>begin</p><p> S1，S2，S3，S4，S5，S6：semaphore； //定义信号量</p><p> S1:=0；S2：=0；S3:=0；S4=0；S5:=0；S6:=0；</p><p> Cobegin</p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/81d12d46ca708e06e3f83ccc06dcd12b.png?x-oss-process=style/ruankaodaren\" title=\"81d12d46ca708e06e3f83ccc06dcd12b.png\" alt=\"image.png\"/><br/><p> Coend；</p><p>end.</p>","analyze":"信号量的分配如下图所示。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/58799487a5e192951709b12ceee723c6.png?x-oss-process=style/ruankaodaren\" title=\"58799487a5e192951709b12ceee723c6.png\" alt=\"image.png\"/><br/><p>这里进程P1和P6分别是第一个进程和最后一个进程，因此P1只有V操作，信号量是S2，即V（S2）。P6只有P操作，信号量是S5和S6，结果为P（S5）、P（S6），中间进程P2、P3、P4、P5既有P操作也有V操作 ，分别是P2：P（S1）、V（S2）、V（S3），P3：P（S2）、V（S4），P4：P（S3）、V（S5），P5：P（S4）、V（S6）。</p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930563952693249"],"itemList":[{"id":"794930563923333121","questionId":"794930562035896321","content":"V(S3)和P(S3)","answer":0,"chooseValue":"A"},{"id":"794930563952693249","questionId":"794930562035896321","content":"V(S4)和P(S3)","answer":1,"chooseValue":"B"},{"id":"794930563982053377","questionId":"794930562035896321","content":"P(S3)和P(S4)","answer":0,"chooseValue":"C"},{"id":"794930564011413505","questionId":"794930562035896321","content":"V(S4)和P(S4)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930472864993281","title":"<p><strong>请作答第<span style=\"color: red\">2</span>空。</strong></p><p>某文件系统采用索引节点管理，其磁盘索引块和磁盘数据块大小均为1KB字节且每个文件索引节点有8个地址项iaddr[0]～iaddr[7]，每个地址项大小为4字节，其中iaddr[0]～iaddr[4]采用直接地址索引，iaddr[5]和iaddr[6]采用一级间接地址索引，iaddr[7] 采用二级间接地址索引。若用户要访问文件userA中逻辑块号为4和5的信息，则系统应分别采用（5），该文件系统可表示的单个文件最大长度是（6）KB。</p>","analyze":"<p>每个索引块和磁盘数据块大小为1KB，地址项大小4B，所以一个块可以索引1KB/4B=256个地址。所以：</p><p>直接地址索引范围：0-4，一级间接地址索引范围5-516，二级间接索引的地址范围是517-517+256*256+516=66052。逻辑块号为4和5分别在直接地址范围和一级间接地址范围。由于地址是从0开始，所以单个文件最大长度是66053。</p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930474765012993"],"itemList":[{"id":"794930474718875649","questionId":"794930472864993281","content":"517","answer":0,"chooseValue":"A"},{"id":"794930474739847169","questionId":"794930472864993281","content":"1029","answer":0,"chooseValue":"B"},{"id":"794930474752430081","questionId":"794930472864993281","content":"65797","answer":0,"chooseValue":"C"},{"id":"794930474765012993","questionId":"794930472864993281","content":"66053","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930452870746113","title":"<p><strong>请作答第<span style=\"color: red\">2</span>空。</strong></p><p>某数据库中有员工关系E、产品关系P、仓库关系W和库存关系I，其中：员工关系E(employeeID，name，department)中的属性为：员工编号，姓名，部门：产品关系P (productID，name，model，size，color)中的属性为：产品编号，产品名称，型号，尺寸，颜色：仓库关系W(warehouseID，name，address，employeeID.中的属性为：仓库编号，仓库名称，地址，负责人编号；库存关系I(warehouseID，productlD，quantity)中的属性为仓库编号，产品编号和产品数量。</p><p>a．若要求仓库关系的负责人引用员工关系的员工编号，员工关系E的员工编号、仓库关系w的仓库编号和产品关系P的产品编号不能为空且唯一标识一个记录，并且仓库的地址不能为空，则依次要满足的完整性约束是（请作答此空）。</p><p>b．若需得到每种产品的名称和该产品的总库存量，则对应的查询语句为：</p><p> SELELCT name, SUM(quantity)</p><p> FROM P, I</p><p> WHERE （）</p><p> c．若需得到在所有仓库中都存在的产品的名称，则对应的查询语句为：</p><p><br/></p><p> SELECT name FROM P</p><p> WHERE (50) </p><p> (SELECT * FROM W</p><p> WHERE NOT EXISTS</p><p> (SELECT * FROM I</p><p> WHERE P. productID=l.productID AND W. warehouselD=l.warehouseID.)</p>","analyze":"<p>SQL查询是数据库中非常重要的内容。该SQL查询要求对查询结果进行分组，即具有相同名称的产品的元组为一组，然后计算每组的库存数量。由此可排除A、B和D，所以本题正确答案为C。 </p>","multi":0,"questionType":1,"answer":"C","chooseItem":["794930454850457601"],"itemList":[{"id":"794930454787543041","questionId":"794930452870746113","content":"P. productID=l.productID;","answer":0,"chooseValue":"A"},{"id":"794930454821097473","questionId":"794930452870746113","content":"P. productID=I.productID ORDER BY name;","answer":0,"chooseValue":"B"},{"id":"794930454850457601","questionId":"794930452870746113","content":"P. productID=I.productID GROUP BY name;","answer":1,"chooseValue":"C"},{"id":"794930454879817729","questionId":"794930452870746113","content":"P. productlD=I.productlD GROUP BY name, quantity;","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930521405673473","title":"<p><strong>请作答第<span style=\"color: red\">2</span>空。</strong></p><p>进程P1、P2、P3、P4、P5和P6的前趋图如下所示。用PV操作控制这6个进程之间同步与互斥的程序如下，程序中的空①和空②处应分别为（）， 空③和空④处应分别为（），空⑤和空⑥处应分别为（）。</p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/25d38ab44ec1c8af4c251e6332a68021.png?x-oss-process=style/ruankaodaren\" title=\"25d38ab44ec1c8af4c251e6332a68021.png\" alt=\"image.png\"/><br/><p>begin</p><p> S1，S2，S3，S4，S5，S6：semaphore； //定义信号量</p><p> S1:=0；S2：=0；S3:=0；S4=0；S5:=0；S6:=0；</p><p> Cobegin</p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/b8bc533ea9307201cdc97794652b5b45.png?x-oss-process=style/ruankaodaren\" title=\"b8bc533ea9307201cdc97794652b5b45.png\" alt=\"image.png\"/><p><br/></p> Coend；<br/><p>end.</p>","analyze":"<p>信号量的分配如下图所示。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/ffb309b13f7a8fa02e277f1c8d2fb28e.png?x-oss-process=style/ruankaodaren\" title=\"ffb309b13f7a8fa02e277f1c8d2fb28e.png\" alt=\"image.png\"/> </p><p>这里进程P1和P6分别是第一个进程和最后一个进程，因此P1只有V操作，信号量是S1，即V（S1）。P6只有P操作，信号量是S5和S6，结果为P（S5）、P（S6），中间进程P2、P3、P4、P5既有P操作也有V操作 ，分别是P2：P（S1）、V（S2）、V（S3），P3：P（S2）、V（S4），P4：P（S3）、V（S5），P5：P（S4）、V（S6）。</p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930523649626113"],"itemList":[{"id":"794930523632848897","questionId":"794930521405673473","content":"V(S3)和P(S3)","answer":0,"chooseValue":"A"},{"id":"794930523649626113","questionId":"794930521405673473","content":"V(S4)和P(S3)","answer":1,"chooseValue":"B"},{"id":"794930523666403329","questionId":"794930521405673473","content":"P(S3)和P(S4)","answer":0,"chooseValue":"C"},{"id":"794930523678986241","questionId":"794930521405673473","content":"V(S4)和P(S4)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930509850365953","title":"<p><strong>请作答第<span style=\"color: red\">2</span>空。</strong></p><p>若某分页管理的虚拟存储器共有8个页面，每页为1024个字节，实际主存为 4096 个字节，采用页表法进行地址映像。若页表的内容如下表所示，则发生页面失效的全部虚页号为（ ），虚拟地址1023所对应的主存实地址页内偏移地址为（ ），主存实地址为（ ）。</p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/ddecbd414bb1380bae73df6cd736b447.jpg?x-oss-process=style/ruankaodaren\" title=\"ddecbd414bb1380bae73df6cd736b447.jpg\" alt=\"1.jpg\"/>","analyze":"在页表中已经列出未装入的虚页号分别是2、3、5、7，也就是说这些页面不在主存中。现已给出虚拟地址为1023，其虚页号应为∶虚地址/页面大小，那1023/1024=0，故其虚页号应为 0。页内编移量等于虚地址-（虚页号×页面大小），即 1023-0=1023。实存地址为∶实页号×页面大小+页内编移地址，查表可以看到它所对应的实页号为3，即3×1024+1023=4095，得到实存地址为4095。","multi":0,"questionType":1,"answer":"B","chooseItem":["794930511695859713"],"itemList":[{"id":"794930511679082497","questionId":"794930509850365953","content":"656","answer":0,"chooseValue":"A"},{"id":"794930511695859713","questionId":"794930509850365953","content":"1023","answer":1,"chooseValue":"B"},{"id":"794930511712636929","questionId":"794930509850365953","content":"2047","answer":0,"chooseValue":"C"},{"id":"794930511729414145","questionId":"794930509850365953","content":"4095","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930424588554241","title":"<p><strong>请作答第<span style=\"color: red\">2</span>空。</strong></p><p>进程P1、P2、P3、P4、P5和P6的前趋图如下所示：</p><p><br/></p><p>若用PV操作控制这6个进程的同步与互斥的程序如下，那么程序中的空a、空b和空c处应分别为（1）；空d和空e处应分别为（2）；空f和空g处应分别为（3）。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/1ca45bb5217f7013a881f17c5ac96727.jpg?x-oss-process=style/ruankaodaren\" title=\"1ca45bb5217f7013a881f17c5ac96727.jpg\" alt=\"1.jpg\"/></p><p>begin</p><p> S1，S2，S3，S4，S5，S6，S7：semaphore； //定义信号量</p><p> S1:=0；S2：=0；S3:=0；S4=0；S5:=0；S6:=0；S7:=0；</p><p> Cobegin</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/2633837fb39cb8b482009769c69d9053.jpg?x-oss-process=style/ruankaodaren\" title=\"2633837fb39cb8b482009769c69d9053.jpg\" alt=\"2.jpg\"/> Coend；</p><p>end</p>","analyze":"根据前驱图P4进程开始运行前必须等待P2和P3进程的通知，需要进行P (S3)操作测试P2进程是否运行完，用P (S4)操作测试P3进程是否运行完，所以空d应填P (S3) P (S4)，P4进程运行结束需要利用V (S6)操作通知P5进程，所以空e应填V (S6)。","multi":0,"questionType":1,"answer":"B","chooseItem":["794930426484379649"],"itemList":[{"id":"794930426463408129","questionId":"794930424588554241","content":"V(S3)V(S4)和V(S6）","answer":0,"chooseValue":"A"},{"id":"794930426484379649","questionId":"794930424588554241","content":"P(S3)P(S4)和V(S6)","answer":1,"chooseValue":"B"},{"id":"794930426501156865","questionId":"794930424588554241","content":"P(S3)V(S4)和V(S6）","answer":0,"chooseValue":"C"},{"id":"794930426517934081","questionId":"794930424588554241","content":"P(S3)V(S4)和P(S6)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930576321695745","title":"<p><strong>请作答第<span style=\"color: red\">2</span>空。</strong></p><p>某文件系统采用索引节点管理，其磁盘索引块和磁盘数据块大小均为1KB且每个文件索引节点有8个地址项iaddr[0]～iaddr[7]，每个地址项大小为4字节，其中iaddr[0]～iaddr[4]采用直接地址索引，iaddr[5]和iaddr[6]采用一级间接地址索引，iaddr[7] 采用二级间接地索引。若用户要访问文件userA中逻辑块号为4和5的信息，则系统应分别采用（），该文件系统可表示的单个文件最大长度是（）KB。</p>","analyze":"<p>每个索引块和磁盘数据块大小为1KB，地址项大小4B，所以一个块可以索引1KB/4B=256个地址。所以：</p><p>直接地址索引范围：0-4，一级间接地址索引范围5-516，二级间接索引的地址范围是517-517+256*256+516=66052。逻辑块号为4和5分别在直接地址范围和一级间接地址范围。由于地址是从0开始，所以单个文件最大长度是66053。</p>","multi":0,"questionType":1,"answer":"D","chooseItem":["794930578230104065"],"itemList":[{"id":"794930578171383809","questionId":"794930576321695745","content":"517","answer":0,"chooseValue":"A"},{"id":"794930578188161025","questionId":"794930576321695745","content":"1029","answer":0,"chooseValue":"B"},{"id":"794930578209132545","questionId":"794930576321695745","content":"65797","answer":0,"chooseValue":"C"},{"id":"794930578230104065","questionId":"794930576321695745","content":"66053","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930487150792705","title":"<p><strong>请作答第<span style=\"color: red\">2</span>空。</strong></p><p>进程P1、P2、P3和P4的前趋图如下所示<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/654def81b9879fc91d9e01d0ad176bb8.png?x-oss-process=style/ruankaodaren\" title=\"654def81b9879fc91d9e01d0ad176bb8.png\" alt=\"image.png\"/><br/></p><p>若用PV操作控制进程P1～P4并发执行的过程，则需要设置5个信号量S1、S2、S3、S4和S5，且信号量S1～S5的初值都等于0。下图中a、b和c处应分别填写（ ）；d、e和f处应分别填写（ ）。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/d77f9dfab3a245590fc25f8c21e3e118.png?x-oss-process=style/ruankaodaren\" title=\"d77f9dfab3a245590fc25f8c21e3e118.png\" alt=\"image.png\"/><br/></p>","analyze":"<p>因为P1是P2和P3的前驱，当P1执行完需通知P2和P3，应采用V(S1)V(S2)操作分别通知P2和P3，故a处应填写V(S1)V(S2)；又因为P2是P1和P3的后继，当P2执行前应测试P1和P3是否执行完，应采用P(S1)P(S4)操作测试P1和P3是否执行完，故b处应填写P(S1)P(S4)；同理，P2是P4的前驱，当P2执行完应通知P4，应采用V(S3)操作分别通知P4，故C处应填写V(S3)。</p><p>因为P3是P1的后继，当P3执行前应测试P1是否执行完，应采用P(S2)操作测试P1是否执行完，故d处应填写P(S2)；又因为P3是P2和P4的前驱，当P3执行完应通知P2和P4，应采用V(S4)V(S5)操作通知P5，故e处应填写V(S4)V(S5)；P4是P2和P3的后继，当P4执行前应测试P2和P3是否执行完，应采用P(S3)P(S5)操作测试P2和P3是否执行完，故f处应填写P(S3)P(S5)。</p>","multi":0,"questionType":1,"answer":"A","chooseItem":["794930489013063681"],"itemList":[{"id":"794930489013063681","questionId":"794930487150792705","content":"P(S2)、V(S3)V(S5)和P(S4)P(S5)","answer":1,"chooseValue":"A"},{"id":"794930489029840897","questionId":"794930487150792705","content":"V(S2)、P(S3)V(S5)和V(S4)P(S5)","answer":0,"chooseValue":"B"},{"id":"794930489046618113","questionId":"794930487150792705","content":"P(S2)、V(S3)P(S5)和P(S4)V(S5)","answer":0,"chooseValue":"C"},{"id":"794930489063395329","questionId":"794930487150792705","content":"V(S2)、V(S3)P(S5)和P(S4)V(S5)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930455798370305","title":"<p><strong>请作答第<span style=\"color: red\">3</span>空。</strong></p><p>某数据库中有员工关系E、产品关系P、仓库关系W和库存关系I，其中：员工关系E(employeeID，name，department)中的属性为：员工编号，姓名，部门：产品关系P (productID，name，model，size，color)中的属性为：产品编号，产品名称，型号，尺寸，颜色：仓库关系W(warehouseID，name，address，employeeID.中的属性为：仓库编号，仓库名称，地址，负责人编号；库存关系I(warehouseID，productlD，quantity)中的属性为仓库编号，产品编号和产品数量。</p><p>a．若要求仓库关系的负责人引用员工关系的员工编号，员工关系E的员工编号、仓库关系w的仓库编号和产品关系P的产品编号不能为空且唯一标识一个记录，并且仓库的地址不能为空，则依次要满足的完整性约束是（请作答此空）。</p><p>b．若需得到每种产品的名称和该产品的总库存量，则对应的查询语句为：</p><p> SELELCT name, SUM(quantity)</p><p> FROM P, I</p><p> WHERE （）</p><p> c．若需得到在所有仓库中都存在的产品的名称，则对应的查询语句为：</p><p><br/></p><p> SELECT name FROM P</p><p> WHERE (50) </p><p> (SELECT * FROM W</p><p> WHERE NOT EXISTS</p><p> (SELECT * FROM I</p><p> WHERE P. productID=l.productID AND W. warehouselD=l.warehouseID.)</p>","analyze":"得到在所有仓库中都存在的产品的名称的查询要求可等价理解为：查询这样的产品，没有一个仓库不保存该产品。所以本题正确答案为B。 ","multi":0,"questionType":1,"answer":"B","chooseItem":["794930457744527361"],"itemList":[{"id":"794930457715167233","questionId":"794930455798370305","content":"EXISTS","answer":0,"chooseValue":"A"},{"id":"794930457744527361","questionId":"794930455798370305","content":"NOTEXISTS","answer":1,"chooseValue":"B"},{"id":"794930457773887489","questionId":"794930455798370305","content":"IN","answer":0,"chooseValue":"C"},{"id":"794930457803247617","questionId":"794930455798370305","content":"NOTIN","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930547662016513","title":"<p><strong>请作答第<span style=\"color: red\">3</span>空。</strong></p><p>进程P1、P2、P3、P4和P5的前趋图如下图所示：</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/441039c80db53045b3b7ac5808fe4ed6.jpg?x-oss-process=style/ruankaodaren\" title=\"441039c80db53045b3b7ac5808fe4ed6.jpg\" alt=\"111.jpg\" width=\"242\" height=\"116\"/></p><p>若用PV操作控制这5个进程的同步与互斥的程序如下，那么程序中的空①和空②处应分别为 （2） ；空③和空④处应分别为 （3） ；空⑤和空⑥处应分别为 （4） 。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/389d6a23e71945c690c0019c301e0946.png?x-oss-process=style/ruankaodaren\" title=\"389d6a23e71945c690c0019c301e0946.png\" alt=\"image.png\" width=\"206\" height=\"188\"/></p>","analyze":"<p>PV操作中的P，是荷兰语Passeren的缩写，意为“通过（pass）”；V是荷兰语vrijgeven的缩写，意为“释放（give）”。</p><p>根据前驱图，进程P1执行完毕后需要利用V（S1）、V（S2）通知进程P2、P3，所以①填V（S2）。</p><p>进程P2中，需要利用P（S1）判断前驱进程P1是否运行完毕。因此②填P（S1）。进程P2执行完毕后需要利用V（S3）、V（S4）、V（S5）通知进程P3、P4、P5。</p><p>进程P3中，需要利用P（S2）、P（S3）判断前驱进程P1、P2是否运行完毕，所以③填P（S3）。进程P3执行完毕后需要利用V（S6）通知进程P5，所以④填V（S6）。</p><p>进程P4中，需要利用P（S4）判断前驱进程P2是否运行完毕。进程P4执行完毕后需要利用V（S7）通知进程P5，所以⑤填P（S4）。</p><p>进程P5中，需要利用P（S5）、P（S6）、P（S7）判断前驱进程P2、P3、P4是否运行完毕，所以⑥填P（S6）P（S7）。</p><p>将前驱图标明信号，如下图所示，可以更直观的解题。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/0d4d592bf37c56c5b38e0a80c08f8069.jpg?x-oss-process=style/ruankaodaren\" title=\"0d4d592bf37c56c5b38e0a80c08f8069.jpg\" alt=\"111.jpg\"/></p>","multi":0,"questionType":1,"answer":"B","chooseItem":["794930549549453313"],"itemList":[{"id":"794930549524287489","questionId":"794930547662016513","content":"P（S5）和V（S6）P（S7）","answer":0,"chooseValue":"A"},{"id":"794930549549453313","questionId":"794930547662016513","content":"P（S4）和P（S6）P（S7）","answer":1,"chooseValue":"B"},{"id":"794930549574619137","questionId":"794930547662016513","content":"V（S5）和V（S6）P（S7）","answer":0,"chooseValue":"C"},{"id":"794930549595590657","questionId":"794930547662016513","content":"V（S6）和P（S5）P（S7）","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930427436486657","title":"<p><strong>请作答第<span style=\"color: red\">3</span>空。</strong></p><p>进程P1、P2、P3、P4、P5和P6的前趋图如下所示：</p><p><br/></p><p>若用PV操作控制这6个进程的同步与互斥的程序如下，那么程序中的空a、空b和空c处应分别为（1）；空d和空e处应分别为（2）；空f和空g处应分别为（3）。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/1ca45bb5217f7013a881f17c5ac96727.jpg?x-oss-process=style/ruankaodaren\" title=\"1ca45bb5217f7013a881f17c5ac96727.jpg\" alt=\"1.jpg\"/></p><p>begin</p><p> S1，S2，S3，S4，S5，S6，S7：semaphore； //定义信号量</p><p> S1:=0；S2：=0；S3:=0；S4=0；S5:=0；S6:=0；S7:=0；</p><p> Cobegin</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/2633837fb39cb8b482009769c69d9053.jpg?x-oss-process=style/ruankaodaren\" title=\"2633837fb39cb8b482009769c69d9053.jpg\" alt=\"2.jpg\"/> Coend；</p><p>end</p>","analyze":"根据前驱图P5进程开始运行前必须等待P3进程的通知，需要用P (S5)操作测试P3进程是否运行完，故空f应填写P (S5)：P5进程运行结束需要利用V操作通知P6进程，故空g应填写V(S7)。","multi":0,"questionType":1,"answer":"C","chooseItem":["794930429332312065"],"itemList":[{"id":"794930429302951937","questionId":"794930427436486657","content":"V(S5)和V(S7）","answer":0,"chooseValue":"A"},{"id":"794930429315534849","questionId":"794930427436486657","content":"P(5)和P(S7)","answer":0,"chooseValue":"B"},{"id":"794930429332312065","questionId":"794930427436486657","content":"P(S5)和V(S7）","answer":1,"chooseValue":"C"},{"id":"794930429344894977","questionId":"794930427436486657","content":"V(S5)和P(S7)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930564925771777","title":"<p><strong>请作答第<span style=\"color: red\">3</span>空。</strong></p><p>进程P1、P2、P3、P4、P5和P6的前趋图如下所示。用PV操作控制这6个进程之间同步与互斥的程序如下，程序中的空①和空②处应分别为（）， 空③和空④处应分别为（），空⑤和空⑥处应分别为（）。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/80140d24578af1c13bef5bcdcbe6c25b.png?x-oss-process=style/ruankaodaren\" title=\"80140d24578af1c13bef5bcdcbe6c25b.png\" alt=\"image.png\"/><br/></p><p>begin</p><p> S1，S2，S3，S4，S5，S6：semaphore； //定义信号量</p><p> S1:=0；S2：=0；S3:=0；S4=0；S5:=0；S6:=0；</p><p> Cobegin</p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/81d12d46ca708e06e3f83ccc06dcd12b.png?x-oss-process=style/ruankaodaren\" title=\"81d12d46ca708e06e3f83ccc06dcd12b.png\" alt=\"image.png\"/><br/><p> Coend；</p><p>end.</p>","analyze":"信号量的分配如下图所示。<br/><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/58799487a5e192951709b12ceee723c6.png?x-oss-process=style/ruankaodaren\" title=\"58799487a5e192951709b12ceee723c6.png\" alt=\"image.png\"/><br/><p>这里进程P1和P6分别是第一个进程和最后一个进程，因此P1只有V操作，信号量是S2，即V（S2）。P6只有P操作，信号量是S5和S6，结果为P（S5）、P（S6），中间进程P2、P3、P4、P5既有P操作也有V操作 ，分别是P2：P（S1）、V（S2）、V（S3），P3：P（S2）、V（S4），P4：P（S3）、V（S5），P5：P（S4）、V（S6）。</p>","multi":0,"questionType":1,"answer":"A","chooseItem":["794930566792237057"],"itemList":[{"id":"794930566792237057","questionId":"794930564925771777","content":"V(S6)和P(S5)","answer":1,"chooseValue":"A"},{"id":"794930566825791489","questionId":"794930564925771777","content":"V(S5)和P(S6)","answer":0,"chooseValue":"B"},{"id":"794930566859345921","questionId":"794930564925771777","content":"P(S5)和V(S6)","answer":0,"chooseValue":"C"},{"id":"794930566884511745","questionId":"794930564925771777","content":"P(S5)和V(S5)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930512647966721","title":"<p><strong>请作答第<span style=\"color: red\">3</span>空。</strong></p><p>若某分页管理的虚拟存储器共有8个页面，每页为1024个字节，实际主存为 4096 个字节，采用页表法进行地址映像。若页表的内容如下表所示，则发生页面失效的全部虚页号为（ ），虚拟地址1023所对应的主存实地址页内偏移地址为（ ），主存实地址为（ ）。</p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/ddecbd414bb1380bae73df6cd736b447.jpg?x-oss-process=style/ruankaodaren\" title=\"ddecbd414bb1380bae73df6cd736b447.jpg\" alt=\"1.jpg\"/>","analyze":"在页表中已经列出未装入的虚页号分别是2、3、5、7，也就是说这些页面不在主存中。现已给出虚拟地址为1023，其虚页号应为∶虚地址/页面大小，那1023/1024=0，故其虚页号应为 0。页内编移量等于虚地址-（虚页号×页面大小），即 1023-0=1023。实存地址为∶实页号×页面大小+页内编移地址，查表可以看到它所对应的实页号为3，即3×1024+1023=4095，得到实存地址为4095。","multi":0,"questionType":1,"answer":"D","chooseItem":["794930514573152257"],"itemList":[{"id":"794930514510237697","questionId":"794930512647966721","content":"1023","answer":0,"chooseValue":"A"},{"id":"794930514531209217","questionId":"794930512647966721","content":"656","answer":0,"chooseValue":"B"},{"id":"794930514552180737","questionId":"794930512647966721","content":"2047","answer":0,"chooseValue":"C"},{"id":"794930514573152257","questionId":"794930512647966721","content":"4095","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930524748533761","title":"<p><strong>请作答第<span style=\"color: red\">3</span>空。</strong></p><p>进程P1、P2、P3、P4、P5和P6的前趋图如下所示。用PV操作控制这6个进程之间同步与互斥的程序如下，程序中的空①和空②处应分别为（）， 空③和空④处应分别为（），空⑤和空⑥处应分别为（）。</p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/25d38ab44ec1c8af4c251e6332a68021.png?x-oss-process=style/ruankaodaren\" title=\"25d38ab44ec1c8af4c251e6332a68021.png\" alt=\"image.png\"/><br/><p>begin</p><p> S1，S2，S3，S4，S5，S6：semaphore； //定义信号量</p><p> S1:=0；S2：=0；S3:=0；S4=0；S5:=0；S6:=0；</p><p> Cobegin</p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/b8bc533ea9307201cdc97794652b5b45.png?x-oss-process=style/ruankaodaren\" title=\"b8bc533ea9307201cdc97794652b5b45.png\" alt=\"image.png\"/><p><br/></p> Coend；<br/><p>end.</p>","analyze":"<p>信号量的分配如下图所示。</p><p><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/ef436d1036539e8668cd344bf50314c0.png?x-oss-process=style/ruankaodaren\" title=\"ef436d1036539e8668cd344bf50314c0.png\" alt=\"image.png\"/> </p><p>这里进程P1和P6分别是第一个进程和最后一个进程，因此P1只有V操作，信号量是S1，即V（S1）。P6只有P操作，信号量是S5和S6，结果为P（S5）、P（S6），中间进程P2、P3、P4、P5既有P操作也有V操作 ，分别是P2：P（S1）、V（S2）、V（S3），P3：P（S2）、V（S4），P4：P（S3）、V（S5），P5：P（S4）、V（S6）。</p>","multi":0,"questionType":1,"answer":"A","chooseItem":["794930526950543361"],"itemList":[{"id":"794930526950543361","questionId":"794930524748533761","content":"V(S6)和P(S5)","answer":1,"chooseValue":"A"},{"id":"794930526967320577","questionId":"794930524748533761","content":"V(S5)和P(S6)","answer":0,"chooseValue":"B"},{"id":"794930526988292097","questionId":"794930524748533761","content":"P(S5)和V(S6)","answer":0,"chooseValue":"C"},{"id":"794930527005069313","questionId":"794930524748533761","content":"P(S5)和V(S5)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"794930597372907521","title":"<br><p><br/></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><strong><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">试题三</span></span></strong><strong><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">（共</span>25分）</span></strong><strong><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></strong></p><p class=\"MsoNormal\" style=\"text-indent: 21pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">请详细阅读有关嵌入式实时操作系统方面的描述，回答问题</span>1至问题2。</span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">【说明】</span></span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"text-indent: 21pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">近年来，分区化（</span>Partitioning）技术已被广泛应用于大型嵌入式系统，此项技术重在解决嵌入式系统中多类应用软件共享计算机资源的安全性问题，同时，也可降低软件开发成本，提高软件的可重用能力。某公司承担了一项宇航计算机系统研制任务，要求将以前采用的多处理机系统精简为由单个处理器系统完成，而整体功能应在原有功能不变的基础上，可灵活扩展，并要求原应用软件可被快速移植到新系统。公司将任务交给王工程师组织并承担总体设计工作。在采用何种嵌入式实时操作系统的选型问题上，王工认为宇航系统强调安全性，原系统应用软件功能分布在各自的处理机上，在保持功能不变的情况下，应适当地维持各个软件的相对独立性，因此采用具有分区能力的操作系统（如：VxWorks653）比较合适。</span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"> </span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><strong><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">【问题</span>1】 </span></strong><strong><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></strong></p><p class=\"MsoNormal\" style=\"text-indent: 21pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">图</span>3-1给出了具有分区能力的操作系统架构，该架构支持分区和进程两类调度，并提供了分区的时间、空间隔离保障，保证了应用软件可安全共享计算机资源。请用300字以内文字说明该类操作系统中分区化技术的主要特点。</span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"text-indent: 21pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/737416be8a64fba6621e9509ba663317.png?x-oss-process=style/ruankaodaren\"/></span></p><p class=\"MsoNormal\" style=\"text-indent: 21pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"> </span><span style=\"font-family:宋体\">图</span><span style=\"font-family: 宋体; font-size: 10.5pt; text-align: center;\">3-1 具有分区能力的操作系统架构</span></p><p class=\"MsoNormal\" style=\"text-indent: 21pt; line-height: 150%;\"><strong><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">【问题</span>2】 </span></strong><span style=\"font-family: 宋体; font-size: 10.5pt; text-align: center;\"><br/></span></p><p class=\"MsoNormal\" style=\"text-indent: 21pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">完成该项目总体设计后，王工将软件设计工作交给李工，要求李工在原有软件基础上，完成新环境下的软件设计。经分析，李工统计出了原系统的任务基本情况（见表</span>3-1）。原系统包含三个子系统，为了保证各子系统软件间的相对独立性，将三个子系统移植到新系统的三个分区工作，假设将“显示子系统”、“雷达子系统”和“任务子系统”分别用P1、P2和P3表示，系统的最小时间计时（tick）设为1ms，调度表的主时间框架将是40ms。</span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"text-indent: 21pt; line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">根据表</span>3-1给出的原系统各任务周期和最坏执行时间数据，新系统中的所有任务可被调度，请对此进行分析说明，完善表3-2所示的分区调度表的设计，在空（1）~（10）填写正确内容并将解答填入答题纸的对应栏内。</span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><span style=\"font-family:宋体\">（注：</span>WCET，Worst-CaseExecutionTime）。</span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"><img style=\"max-width:100%;height:auto\" src=\"https://image.chaiding.com/ruankao/2c6e18b889cb6588eb0e8b0534d42cdb.png?x-oss-process=style/ruankaodaren\"/></span></p><p class=\"MsoNormal\" style=\"text-align:center;line-height:150%;\"><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p>","analyze":"<p><strong><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">【问题</span>1】 </span></strong><br/></p><p><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">答：</span></span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">（</span>1）应用软件代码和操作系统代码工作在处理器的不同特权级别上，应用软件的失效不会影响操作系统的运行：</span><strong><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><br/></span></strong></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">（</span>2）每一个分区有自己私有存储资源，分区所占空间是相互隔离的，分区内某进程的失效仅仅只影响到进程所在的分区；</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">（</span>3）操作系统可为分区内应用软件提供多种类型的API服务，使原有应用软件可方便地移植到分区内运行；</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">（</span>4）分区的调度是按预先配置好的时间表进行调度，任何-个分区只能在系统分配给它的时间窗口内运行，任何分区不能、也无法占用其他分区的窗口时间；</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">（</span>5）具有分区能力的操作系统提供健康监控管理能力，它通过操作系统内的故障监测机制，将发现的应用、分区和系统的错误通过注入机制报告健康监控系统，由它进行统一的故障处理；</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">（</span>6）分区化操作系统允许不同安全等级（A-E)的应用软件共享计算机资源，可实现软件验证的最小化、局部化。</span><span style=\"mso-spacerun:'yes';font-family:宋体;line-height:150%;color:#FF0000;font-size:10.5000pt;mso-font-kerning:1.0000pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><strong><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">【问题</span>2】 </span></strong><strong><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></strong></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><strong><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></strong><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">答：</span></span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">所有任务可被调度的分析如下：</span></span><strong><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><br/></span></strong></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">保证所用任务的可调度性必须满足在主时间框架内，系统中所用任务的最坏执行时间（</span>WCET)均被执行至少一次。初步计算如下： </span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\">1(P3T1)≤5ms</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\">1(P1T1)+ l(P2T1)≤10m</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"> 2(P1T2)+ 1(P3T2)≤20m</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\">1(P3T1)*8+1(P1T1)*4+l(P2T1)*4+2(P1T2)*2+1(P3T2)*2+5(P1T3)*1+3(P2T2)<=40ms</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"><span style=\"font-family:宋体\">依据上述三个设计条件，新系统的分区调度表可安排如下：</span></span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\">(1)0 (2) 1 (3) 2 (4) P2 (5) P3</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\">(6)4 (7) 20 (8) 1 (9) null (10) 7</span><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></p><p class=\"MsoNormal\" style=\"line-height: 150%;\"><strong><span style=\"font-family: 宋体; line-height: 150%; font-size: 10.5pt;\"></span></strong></p>","multi":0,"questionType":3,"answer":"<p>见解析</p>","chooseItem":null,"itemList":null,"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237527592751105","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>进程P1、P2、P3、P4、P5和P6的前趋图如下所示：<br><img alt=\"\" width=\"313\" height=\"133\" src=\"https://image.chaiding.com/ruankao/1fcf43b3062424b09d7dafa31551194a.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制这6个进程的同步与互斥的程序如下，那么程序中的空a、空b和空c处应分别为（46）；空d和空e处应分别为（47）；空f和空g处应分别为（48）。<br><img alt=\"\" width=\"589\" height=\"255\" src=\"https://image.chaiding.com/ruankao/0202d870c3a3748cfb7e05159513a4f6.jpg?x-oss-process=style/ruankaodaren\">","analyze":"对于试题（47），根据前驱图P4进程开始运行前必须等待P2和P3进程的通知，需要用P (S3)操作测试P2进程是否运行完，用P (S4)操作测试P3进程是否运行完，所以空d应填P (S3) P (S4), P4进程运行结束需要利用V (S6)操作通知P5进程，所以空e应填V (S6)。","multi":0,"questionType":1,"answer":"B","chooseItem":["796237528494526465"],"itemList":[{"id":"796237528477749249","questionId":"796237527592751105","content":" V(S3)V(S4)和V(S6)","answer":0,"chooseValue":"A"},{"id":"796237528494526465","questionId":"796237527592751105","content":" P(S3)P(S4)和V(S6)","answer":1,"chooseValue":"B"},{"id":"796237528507109377","questionId":"796237527592751105","content":" P(S3)V(S4)和V(S6)","answer":0,"chooseValue":"C"},{"id":"796237528519692289","questionId":"796237527592751105","content":" P(S3)V(S4)和P(S6)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237420252123137","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>当用户开机按下PC机电源开关对，PC机首先执行的是（46），然后加载（47）。","analyze":"本题考查计算机系统方面的基础知识。<br>BIOS引导程序是固化在ROM芯片上的，每当开机时自动执行BIOS引导程序。它主要执行如下任务：<br>•标识和配置所有的即插即用设备。如果系统有即插即用设备的BIOS，系统将搜索和测试所有安装的即插即用设备，并为它们分配DMA通道、IRQ及它们需要的其他设备。<br>•完成加电自检(POST)。加电自检主要检测和测试内存、端口、键盘、视频适配器、磁盘驱动器等基本设备。有一些新版本的系统还支持CD-ROM驱动器。<br>•对引导驱动器可引导分区定位。在CMOS中，用户可以设置系统的引导顺序，以便对引导驱动器的可引导分区重新定位。大多数系统的引导顺序是软件驱动，然后是硬件驱动，其次是CD-ROM驱动器。<br>•加载主引导记录及引导驱动器的分区表，执行主引导记录MBR。<br>主引导记录在硬盘上找到可引导分区后，将其分区引导记录装入内存，并将控制权交给分区引导记录。由分区引导记录定位根目录，再装入操作系统。","multi":0,"questionType":1,"answer":"C","chooseItem":["796237421191647233"],"itemList":[{"id":"796237421145509889","questionId":"796237420252123137","content":" 硬盘上主引导记录","answer":0,"chooseValue":"A"},{"id":"796237421166481409","questionId":"796237420252123137","content":" 硬盘上分区引导记录","answer":0,"chooseValue":"B"},{"id":"796237421191647233","questionId":"796237420252123137","content":" 主板上的BIOS引导程序","answer":1,"chooseValue":"C"},{"id":"796237421216813057","questionId":"796237420252123137","content":" 软盘上的引导记录","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237429060161537","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>微内核体系结构的操作系统（OS)实现时的基本思想是（51），其结构图如下所示，图中①②③④应填写（52）。<br><img src=\"https://image.chaiding.com/ruankao/fe2341391da8acf4da444c74cb078717.jpg?x-oss-process=style/ruankaodaren\">","analyze":"<img alt=\"\" width=\"428\" height=\"84\" src=\"https://image.chaiding.com/ruankao/4c86116c201a6c18361ccd391902adf9.jpg?x-oss-process=style/ruankaodaren\"><br>微内核体系结构的主要特点有：<br>①内核非常小，许多操作系统服务不属于内核，而是运行在内核之上的，这样， 当高层模块更新时内核无须重新编译。<br>②有一个硬件抽象层，内核能方便地移植到其他的硬件体系结构中。因为当需要移植到新的软件或硬件环境中时，只需对与硬件相关的部分稍加修改即可把微内核嵌入到新的硬件环境中，在多数情况下并不需要移植外部服务器或客户应用。<br>③灵活性和扩展性。微内核最大的优点之一就是它的灵活性和扩展性。如果要实现另一个视图，可以增加一个外部服务器。若要想扩展功能，可以增加和扩展内部服务器。 ","multi":0,"questionType":1,"answer":"B","chooseItem":["796237429978714113"],"itemList":[{"id":"796237429961936897","questionId":"796237429060161537","content":" ①进程、文件和存储器服务器②核心态③进程调度、消息通讯等④用户态","answer":0,"chooseValue":"A"},{"id":"796237429978714113","questionId":"796237429060161537","content":" ①进程、文件和存储器服务器②用户态③进程调度、消息通讯等④核心态","answer":1,"chooseValue":"B"},{"id":"796237429995491329","questionId":"796237429060161537","content":" ①进程调度、消息通讯等②用户态③进程、文件和存储等服务器④核心态","answer":0,"chooseValue":"C"},{"id":"796237430012268545","questionId":"796237429060161537","content":" ①进程调度、消息通讯等②核心态③进程、文件和存储等服务器④用户态","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237554234970113","title":"<p><strong>请作答第<span style=\"color: red\">3</span>个空。</strong></p>进程Pl、P2、P3、P4、P5的前趋关系图如下所示：<br><img alt=\"\" width=\"300\" height=\"135\" src=\"https://image.chaiding.com/ruankao/5c6ba6990cacc3975360b177ace6fa87.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制这5个进程的同步与互斥，程序如下:<br><img alt=\"\" src=\"https://image.chaiding.com/ruankao/beb06fffd4d4ee89beecf0be7f280dd5.jpg?x-oss-process=style/ruankaodaren\" height=\"199\" width=\"369\"><br>程序中空a和空b处应分别为（48）；空c和空d处应分别为（49）；空e和空f处应分别为（50） 。","analyze":"根据前驱图，P2进程需要等待P1进程的通知，故需要利用P(S1)操作测试P1进程是否运行完，P2进程运行结束需要利用V操作分别通知P3和P4进程，所以用V(S2)操作通知P3进程，用V(S3)操作通知P4进程。<br>根据前驱图，P3进程开始运行前必须等待P2和P4进程的通知，需要用P(S2)操作测试P2进程是否运行完，用P(S4)操作测试P4进程是否运行完，P2进程运行结束需要利用V(S5)操作通知P5进程。<br>根据前驱图，P4进程开始运行前必须等待P2进程的通知，需要用P(S3)操作测试P2进程是否运行完，故空e应填写P(S3)。P4进程运行结束需要利用V操作通知P3和P5进程，故空g应填写V(S4)V(S6)。","multi":0,"questionType":1,"answer":"B","chooseItem":["796237555249991681"],"itemList":[{"id":"796237555233214465","questionId":"796237554234970113","content":" V(S3)和V(S4)V(S6)","answer":0,"chooseValue":"A"},{"id":"796237555249991681","questionId":"796237554234970113","content":" P(S3)和V(S4)V(S6)","answer":1,"chooseValue":"B"},{"id":"796237555266768897","questionId":"796237554234970113","content":" P(S3)和P(S4)V(S6)","answer":0,"chooseValue":"C"},{"id":"796237555283546113","questionId":"796237554234970113","content":" P(S3)和V(S4)P(S6)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237562975899649","title":"<p><strong>请作答第<span style=\"color: red\">3</span>个空。</strong></p>进程Pl、P2、P3、P4、P5的前趋图如下：<br><img alt=\"\" width=\"249\" height=\"125\" src=\"https://image.chaiding.com/ruankao/846884cfe031bfc5647441c002544d35.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制进程并发执行的过程，则需要设置4个信号量S1、S2、S3和S4，且信号量初值都等于零。下图中a和b应分别填写（50），c和d应分别填写（51），e和f应分别填写（52）。<br><img alt=\"\" width=\"432\" height=\"154\" src=\"https://image.chaiding.com/ruankao/2e99125743e103be09dc197641b5aab0.jpg?x-oss-process=style/ruankaodaren\">","analyze":"根据题意，进程P4和P5要执行需要测试P3有没有消息，故应该在e处填P(S3)，在f处填P(S4)。","multi":0,"questionType":1,"answer":"A","chooseItem":["796237563886063617"],"itemList":[{"id":"796237563886063617","questionId":"796237562975899649","content":" P(S3)和P(S4)","answer":1,"chooseValue":"A"},{"id":"796237563911229441","questionId":"796237562975899649","content":" P(S3)和V(S4)","answer":0,"chooseValue":"B"},{"id":"796237563940589569","questionId":"796237562975899649","content":" V(S3)和V(S4)","answer":0,"chooseValue":"C"},{"id":"796237563957366785","questionId":"796237562975899649","content":" V(S3)和P(S4)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237477277880321","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>某风险投资公司拥有的总资金数为25，分期为项目P1、P2、P3、P4投资，各项目投资情况如下表所示。公司的可用资金数为（50）。若P1和P3分别申请资金数1和2，则公司资金管理处（51）。<br><img alt=\"\" width=\"510\" height=\"144\" src=\"https://image.chaiding.com/ruankao/04b1da45ffe9b6346e472048053c733d.jpg?x-oss-process=style/ruankaodaren\">","analyze":"对于试题（51），因为在图a的情况下，公司资金管理处为P3分配资金2个单位后，能保证项目P3得到所需的最大资金完成项目，归还资金，使得公司的可用资金为8, 而项目P1、P2、P4的尚需资金分别为4、7、6,均小于可用资金，故为项目P3进行投资，投资后公司资金周转状态是安全的。","multi":0,"questionType":1,"answer":"B","chooseItem":["796237478204821505"],"itemList":[{"id":"796237478192238593","questionId":"796237477277880321","content":" 只能先为项目P1进行投资，因为投资后公司资金周转状态是安全的","answer":0,"chooseValue":"A"},{"id":"796237478204821505","questionId":"796237477277880321","content":" 只能先为项目P3进行投资，因为投资后公司资金周转状态是安全的","answer":1,"chooseValue":"B"},{"id":"796237478221598721","questionId":"796237477277880321","content":" 可以同时为项目P1、P3进行投资，因为投资后公司资金周转状态是安全的","answer":0,"chooseValue":"C"},{"id":"796237478238375937","questionId":"796237477277880321","content":" 不能先为项目P3进行投资，因为投资后公司资金周转状态是不安全的","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237498752716801","title":"设某进程的段表如下所示，逻辑地址（46）可以转换为对应的物理地址。<br><img alt=\"\" width=\"298\" height=\"138\" src=\"https://image.chaiding.com/ruankao/8b64de277f29d9b51d111ab00a65bb62.jpg?x-oss-process=style/ruankaodaren\">","analyze":"0段的段长只有600,而逻辑地址（0,1597)中的1597己经越界，不能转换成逻辑地址，而选项A和选项C中都包含逻辑地址(0,1597)所以是错误的。又因为4段的段长只有960,而逻辑地址（4，1066)中的1066己经越界，也不能转换成逻辑地址，而选项D中包含逻辑地址（4,1066)所以是错误的。","multi":0,"questionType":1,"answer":"B","chooseItem":["796237499717406721"],"itemList":[{"id":"796237499700629505","questionId":"796237498752716801","content":" (0,1597)、(1,30)和(3,1390)","answer":0,"chooseValue":"A"},{"id":"796237499717406721","questionId":"796237498752716801","content":" (0,128)、(1,30)和（3,1390)","answer":1,"chooseValue":"B"},{"id":"796237499725795329","questionId":"796237498752716801","content":" (0,1597)、(2,98)和（3,1390)","answer":0,"chooseValue":"C"},{"id":"796237499738378241","questionId":"796237498752716801","content":" (0,128)、 (2,98)和（4,1066)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237344335220737","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>假设某系统采用非抢占式优先级调度算法，若该系统有两个优先级相同的进程P1和P2,各进程的程序段如下所示，若信号量S1和S2的初值都为0。进程P1和P2并发执行后a、b和c的结果分别为：a= (50) ，b= (51) ，c= (52)。<br><img alt=\"\" width=\"296\" height=\"190\" src=\"https://image.chaiding.com/ruankao/0af83ed7afd55470e2637a0eeeabc61c.jpg?x-oss-process=style/ruankaodaren\">","analyze":"本题考查操作系统PV操作方面的基础知识。<br>假设P1先运行，系统执行“a:=1; a:=a+2”后a=3;执行“V (S1)”后，S1=1, P继续执行；执行“c:=a+l”后，c=4;执行“P (S2)”后，S2=-1，P1被阻塞。<br>此时轮到P2运行，系统执行“b:=1; b:=b+2”后b=3;执行“P (S1)”后，S1=0,P2继续执行；执行“b:=a+b”后，b=6;执行“V (S2)”后，S2=0，唤醒P1, P2继续执行；执行“c:=b+c”后，c=10，P2运行结束。<br>此时轮到P1运行，系统执行“a:=a+c”后，a=13, P1运行结束。<br>综上分析可见，进程P1和P2并发执行后a、b和c的结果分别为：a=13, b=6, c=10。","multi":0,"questionType":1,"answer":"D","chooseItem":["796237345316687873"],"itemList":[{"id":"796237345278939137","questionId":"796237344335220737","content":" 6","answer":0,"chooseValue":"A"},{"id":"796237345295716353","questionId":"796237344335220737","content":" 7","answer":0,"chooseValue":"B"},{"id":"796237345308299265","questionId":"796237344335220737","content":" 10","answer":0,"chooseValue":"C"},{"id":"796237345316687873","questionId":"796237344335220737","content":" 13","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237322994601985","title":"CPU访问存储器时，被访问数据倾向于聚集在一个较小的连续区域中，若一个存储单元已被访问，则其邻近的存储单元有可能还要被访问，该特性被称为（16）。","analyze":"本题考查计算机系统中的存储系统基础知识。<br>计算机系统中的局部性原理是指程序访问代码和数据的不均匀性，它包括时间局部性和空间局部性：时间局部性是指如果某位置已被访问，则该位置很可能在短时间内还要再次被访问；空间局部性是指如果某位置已被访问，则其临近位置很可能还要被访问。 高速缓存的工作机制体现了局部性原理。","multi":0,"questionType":1,"answer":"D","chooseItem":["796237323980263425"],"itemList":[{"id":"796237323913154561","questionId":"796237322994601985","content":" 指令局部性","answer":0,"chooseValue":"A"},{"id":"796237323934126081","questionId":"796237322994601985","content":" 数据局部性","answer":0,"chooseValue":"B"},{"id":"796237323955097601","questionId":"796237322994601985","content":" 时间局部性","answer":0,"chooseValue":"C"},{"id":"796237323980263425","questionId":"796237322994601985","content":" 空间局部性","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237400689889281","title":"在高级语言程序中，使用（17）访问保存在变量中的数据。","analyze":"本题考查存储系统知识。<br>在高级语言程序中，对存储数据的位置进行了抽象，采用的是虚拟地址。在程序运行时再进行地址变换，分为内部地址变换与外部地址变换。虚拟存储系统按照地址映像方式把虚拟地址转换为主存物理地址称为内部地址变换。如果要访问的指令或数据已经在主存中，则命中，直接访问即可，否则就发生了页面失效，此时再进行外部地址变换，即将虚拟地址变换为辅存物理地址。","multi":0,"questionType":1,"answer":"B","chooseItem":["796237401600053249"],"itemList":[{"id":"796237401583276033","questionId":"796237400689889281","content":" 物理地址","answer":0,"chooseValue":"A"},{"id":"796237401600053249","questionId":"796237400689889281","content":" 逻辑地址","answer":1,"chooseValue":"B"},{"id":"796237401612636161","questionId":"796237400689889281","content":" 主存地址","answer":0,"chooseValue":"C"},{"id":"796237401625219073","questionId":"796237400689889281","content":" 辅存地址","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237486958333953","title":"若操作系统把一条命令的执行结果输出给下一条命令，作为它的输入，并加以处理，这种机制称为（46）。","analyze":"本题考查应试者对操作系统进程管道通信方面的基本概念的掌握程度。<br>管道通信是一种共享文件模式，它基于文件系统，连接于两个通信进程之间，以先进先出的方式实现消息的单向传送。管道是一个特殊文件，在内核中通过文件描述符表示。一个管道总是连接两个命令，将左边命令的标准输出与右边命令的标准输入相连，于是左边命令的输出结果就直接成了右边命令的输入。","multi":0,"questionType":1,"answer":"B","chooseItem":["796237487843332097"],"itemList":[{"id":"796237487830749185","questionId":"796237486958333953","content":" 链接","answer":0,"chooseValue":"A"},{"id":"796237487843332097","questionId":"796237486958333953","content":" 管道（线）","answer":1,"chooseValue":"B"},{"id":"796237487851720705","questionId":"796237486958333953","content":" 输入重定向","answer":0,"chooseValue":"C"},{"id":"796237487864303617","questionId":"796237486958333953","content":" 输出重定向","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237560073441281","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>进程Pl、P2、P3、P4、P5的前趋图如下：<br><img alt=\"\" width=\"249\" height=\"125\" src=\"https://image.chaiding.com/ruankao/0c807fcfc7c465963f128ec49f097cd0.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制进程并发执行的过程，则需要设置4个信号量S1、S2、S3和S4，且信号量初值都等于零。下图中a和b应分别填写（50），c和d应分别填写（51），e和f应分别填写（52）。<br><img alt=\"\" width=\"432\" height=\"154\" src=\"https://image.chaiding.com/ruankao/65b605cfc2cd190df5e6d816124fe5a5.jpg?x-oss-process=style/ruankaodaren\">","analyze":"根据题意，进程P3要执行需要测试P1、P2有没有消息，应该在c处填P(S1);P(S2)；当P3执行完毕需要使用V操作通知P4和P5,即在d处填V(S3)、V(S4)。","multi":0,"questionType":1,"answer":"A","chooseItem":["796237560958439425"],"itemList":[{"id":"796237560958439425","questionId":"796237560073441281","content":" P(S1)、P (S2)和V(S3)、V(S4)","answer":1,"chooseValue":"A"},{"id":"796237560975216641","questionId":"796237560073441281","content":" P(S1)、P(S2)和P(S3)、P(S4)","answer":0,"chooseValue":"B"},{"id":"796237560991993857","questionId":"796237560073441281","content":" V(S1)、V(S2)和P(S3)、P(S4)","answer":0,"chooseValue":"C"},{"id":"796237561012965377","questionId":"796237560073441281","content":" V(S1)、V(S2)和V(S3)、V(S4)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237568814370817","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>进程P有6个页面，页号分别为0~5，页面大小为4K，页面变换表如下所示。表中状态位等于1和0分别表示页面在内存和不在内存。假设系统给进程P分配了4个存储块，进程P要访问的逻辑地址为十六进制1165H,那么该地址经过变换后，其物理地址应为十六进制（46）：如果进程P要访问的页面4不在内存，那么应该淘汰页号为（47）的页面。<br><img alt=\"\" width=\"317\" height=\"149\" src=\"https://image.chaiding.com/ruankao/04d0c5886247a3d93661f3e652aa32c1.jpg?x-oss-process=style/ruankaodaren\">","analyze":"本题考查操作系统存储管理方面的基础知识。<br>根据题意，页面大小为4K,逻辑地址为十六进制1165H, 其页号为1,页内地址为165H，查页表后可知页帧号（物理块号）为3,该地址经过变换后，其物理地址应为页帧号3拼上页内地址165H，即十六进制3165H。<br>根据题意，页面变换表中状态位等于1和0分别表示页面在内存或不在内存，所以0、1、2和5号页面在内存。当访问的页面4不在内存时，系统应该首先淘汰未被访问的页面，因为根据程序的局部性原理，最近未被访问的页面下次被访问的概率更小；如果页面最近都被访问过，应该先淘汰未修改过的页面，因为未修改过的页面内存与辅存一致，故淘汰时无需写回辅存，使系统页面置换代价小。经上述分析，0、1和2号页面都是最近被访问过的，但5号页面最近未被访问过，故应该淘汰5号页面。","multi":0,"questionType":1,"answer":"D","chooseItem":["796237569749700609"],"itemList":[{"id":"796237569703563265","questionId":"796237568814370817","content":" 0","answer":0,"chooseValue":"A"},{"id":"796237569716146177","questionId":"796237568814370817","content":" 1","answer":0,"chooseValue":"B"},{"id":"796237569732923393","questionId":"796237568814370817","content":" 2","answer":0,"chooseValue":"C"},{"id":"796237569749700609","questionId":"796237568814370817","content":" 5","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237392754266113","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>在计算机系统中，若一个存储单元被访问，这个存储单元有可能很快会再被访问，该特性被称为（16）；这个存储单元及其邻近的存储单元有可能很快会再被访问，该特性被称为（17）。","analyze":"局部性原理是指在指定时间内，程序趋于在有限的内存区域内重复访问。通常将局部性分为空间局部性和时间局部性。空间局部性是指已访问过的内存地址附近的位置很可能被连续访问。时间局部性是指已访问过的内存地址在较短的时间内还可能被多次访问。","multi":0,"questionType":1,"answer":"C","chooseItem":["796237393714761729"],"itemList":[{"id":"796237393664430081","questionId":"796237392754266113","content":" 程序局部性","answer":0,"chooseValue":"A"},{"id":"796237393693790209","questionId":"796237392754266113","content":" 空间局部性","answer":0,"chooseValue":"B"},{"id":"796237393714761729","questionId":"796237392754266113","content":" 时间局部性","answer":1,"chooseValue":"C"},{"id":"796237393739927553","questionId":"796237392754266113","content":" 数据局部性","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237350039474177","title":"<p><strong>请作答第<span style=\"color: red\">3</span>个空。</strong></p>假设某系统采用非抢占式优先级调度算法，若该系统有两个优先级相同的进程P1和P2,各进程的程序段如下所示，若信号量S1和S2的初值都为0。进程P1和P2并发执行后a、b和c的结果分别为：a= (50) ，b= (51) ，c= (52)。<br><img alt=\"\" width=\"296\" height=\"190\" src=\"https://image.chaiding.com/ruankao/0e632f19dcb3e801f53e6c86121aa9e1.jpg?x-oss-process=style/ruankaodaren\">","analyze":"本题考查操作系统PV操作方面的基础知识。<br>假设P1先运行，系统执行“a:=1; a:=a+2”后a=3;执行“V (S1)”后，S1=1, P继续执行；执行“c:=a+l”后，c=4;执行“P (S2)”后，S2=-1，P1被阻塞。<br>此时轮到P2运行，系统执行“b:=1; b:=b+2”后b=3;执行“P (S1)”后，S1=0,P2继续执行；执行“b:=a+b”后，b=6;执行“V (S2)”后，S2=0，唤醒P1, P2继续执行；执行“c:=b+c”后，c=10，P2运行结束。<br>此时轮到P1运行，系统执行“a:=a+c”后，a=13, P1运行结束。<br>综上分析可见，进程P1和P2并发执行后a、b和c的结果分别为：a=13, b=6, c=10。","multi":0,"questionType":1,"answer":"C","chooseItem":["796237350949638145"],"itemList":[{"id":"796237350920278017","questionId":"796237350039474177","content":" 4","answer":0,"chooseValue":"A"},{"id":"796237350932860929","questionId":"796237350039474177","content":" 6","answer":0,"chooseValue":"B"},{"id":"796237350949638145","questionId":"796237350039474177","content":" 10","answer":1,"chooseValue":"C"},{"id":"796237350958026753","questionId":"796237350039474177","content":" 13","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237423121027073","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>当用户开机按下PC机电源开关对，PC机首先执行的是（46），然后加载（47）。","analyze":"本题考查计算机系统方面的基础知识。<br>BIOS引导程序是固化在ROM芯片上的，每当开机时自动执行BIOS引导程序。它主要执行如下任务：<br>•标识和配置所有的即插即用设备。如果系统有即插即用设备的BIOS，系统将搜索和测试所有安装的即插即用设备，并为它们分配DMA通道、IRQ及它们需要的其他设备。<br>•完成加电自检(POST)。加电自检主要检测和测试内存、端口、键盘、视频适配器、磁盘驱动器等基本设备。有一些新版本的系统还支持CD-ROM驱动器。<br>•对引导驱动器可引导分区定位。在CMOS中，用户可以设置系统的引导顺序，以便对引导驱动器的可引导分区重新定位。大多数系统的引导顺序是软件驱动，然后是硬件驱动，其次是CD-ROM驱动器。<br>•加载主引导记录及引导驱动器的分区表，执行主引导记录MBR。<br>主引导记录在硬盘上找到可引导分区后，将其分区引导记录装入内存，并将控制权交给分区引导记录。由分区引导记录定位根目录，再装入操作系统。","multi":0,"questionType":1,"answer":"D","chooseItem":["796237424089911297"],"itemList":[{"id":"796237424018608129","questionId":"796237423121027073","content":" 相关支撑软件，如各种设备驱动程序","answer":0,"chooseValue":"A"},{"id":"796237424039579649","questionId":"796237423121027073","content":" 分区引导记录、配置系统，并执行分区引导记录","answer":0,"chooseValue":"B"},{"id":"796237424064745473","questionId":"796237423121027073","content":" 操作系统，如Windows XP、Windows 7、UNIX等","answer":0,"chooseValue":"C"},{"id":"796237424089911297","questionId":"796237423121027073","content":" 主引导记录和引导驱动器的分区表，并执行主引导记录","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237333144817665","title":"下列关于Windows 2003中域的叙述，正确的是（68）。","analyze":"本题考查Windows域的基础知识。域（Domain)是一个共用“目录服务数据库”的计算机和用户的集合，用于实现集中式管理。域是逻辑分组，与网络的物理拓扑无关。域中只能有一个主域控制器但可以有零个或多个备份域控制器。","multi":0,"questionType":1,"answer":"B","chooseItem":["796237334059175937"],"itemList":[{"id":"796237334034010113","questionId":"796237333144817665","content":" 在网络环境中所有的计算机称为一个域","answer":0,"chooseValue":"A"},{"id":"796237334059175937","questionId":"796237333144817665","content":" 同一个域中可以有多个备份域服务器","answer":1,"chooseValue":"B"},{"id":"796237334075953153","questionId":"796237333144817665","content":" 每个域中必须有主域服务器和备份域服务器","answer":0,"chooseValue":"C"},{"id":"796237334092730369","questionId":"796237333144817665","content":" 成员服务器支持活动目录数据库","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237492931022849","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>若某文件系统的目录结构如下图所示，假设用户要访问文件f.java，且当前工作目录为Program,则该文件的全文件名为（46），绝对路径和相对路径分别为（47）。<br><img alt=\"\" width=\"352\" height=\"202\" src=\"https://image.chaiding.com/ruankao/a981f477aa84dd1d53585856e26e3259.jpg?x-oss-process=style/ruankaodaren\">","analyze":"路径名是指操作系统査找文件所经过的目录名以及目录名之间的分隔符构成的。在Windows系统中文件的全文件名为路径名+文件名。<br>按查找文件的起点不同可以将路径分为：绝对路径和相对路径。从根目录开始的路径称为绝对路径；从用户当前工作目录开始的路径称为相对路径，相对路径是随着当前工作目录的变化而改变的。","multi":0,"questionType":1,"answer":"C","chooseItem":["796237493866352641"],"itemList":[{"id":"796237493845381121","questionId":"796237492931022849","content":" Program\\Java-prog\\Sl\\Java-prog\\","answer":0,"chooseValue":"A"},{"id":"796237493857964033","questionId":"796237492931022849","content":" \\Java-prog\\和Program\\Java-prog\\","answer":0,"chooseValue":"B"},{"id":"796237493866352641","questionId":"796237492931022849","content":" \\Program\\Java-prog\\和Java-prog\\","answer":1,"chooseValue":"C"},{"id":"796237493878935553","questionId":"796237492931022849","content":" Java-prog\\和\\Program\\Java-prog\\","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237364203638785","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>假设磁盘块与缓冲区大小相同，每个盘块读入缓冲区的时间为100<img alt=\"\" src=\"https://image.chaiding.com/ruankao/122ed031722b50841866bedec49fafbd.jpg?x-oss-process=style/ruankaodaren\" height=\"17\" width=\"15\">，缓冲区送入用户区的时间是60<img alt=\"\" width=\"14\" height=\"15\" src=\"https://image.chaiding.com/ruankao/b26849662635521680b1aea62bf6844f.jpg?x-oss-process=style/ruankaodaren\">，系统对每个磁盘块数据的处理时间为50<img alt=\"\" width=\"14\" height=\"15\" src=\"https://image.chaiding.com/ruankao/3850cc20b8726729868bb1fea71f06ae.jpg?x-oss-process=style/ruankaodaren\">。若用户需要将大小为10个磁盘块的Filel文件逐块从磁盘读入缓冲区，并送用户区进行处理，那么采用单缓冲需要花费的时间为（51） <img alt=\"\" width=\"14\" height=\"15\" src=\"https://image.chaiding.com/ruankao/68c80c23cbf1a71aa07c4f581fc7418e.jpg?x-oss-process=style/ruankaodaren\">；采用双缓冲需要花费的时间为（52）<img alt=\"\" width=\"14\" height=\"15\" src=\"https://image.chaiding.com/ruankao/cc12772a7f58e7132da9aabde099044b.jpg?x-oss-process=style/ruankaodaren\">。","analyze":"在块设备输入时，假定从磁盘把一块数据输入到缓冲区的时间为T，缓冲区中的数据传送到用户工作区的时间为M，而系统处理（计算）的时间为C，如图（a）所示：<br><img alt=\"\" width=\"358\" height=\"90\" src=\"https://image.chaiding.com/ruankao/f8e29d398ad729cb2cbd897b0c6b58a1.jpg?x-oss-process=style/ruankaodaren\"><br>当第一块数据送入用户工作区后，缓冲区是空闲的可以传送第二块数据。这样第一块数据的处理C1与第二块数据的输入T2是可以并行的，依次类推，如图（b）所示。系统对每一块数据的处理时间为：Max(C，T)+M。因为，当T>C时，处理时间为M+T; 当T<C时，处理时间为M+C。本题每一块数据的处理时间为100+60=160, Filel文件的处理时间为160*10+50。<br><img alt=\"\" width=\"359\" height=\"89\" src=\"https://image.chaiding.com/ruankao/b665a9e398d8d5652de46cd6de483b6d.jpg?x-oss-process=style/ruankaodaren\"><br><br>双缓冲工作方式基本方法是在设备输入时，先将数据输入到缓冲区1，装满后便转向缓冲区2。此时系统可以从缓冲区1中提取数据传送到用户区，最后由系统对数据进行处理，如下图（c）所示：<br><img alt=\"\" width=\"382\" height=\"102\" src=\"https://image.chaiding.com/ruankao/d4ec23cd76b3ca197ad7d16805ab7662.jpg?x-oss-process=style/ruankaodaren\"><br>双缓冲可以实现对缓冲区中数据的输入T和提取M,与CPU的计算C,三者并行工作，如下图（d）所示。所以双缓冲进一步加快了I/O的速度，提高了设备的利用率。 在双缓冲时，系统处理一块数据的时间可以粗略地认为是Max(C，T)。如果C<T,可使块设备连续输入；如果C>T,则可使系统不必等待设备输入。本题每一块数据的处理时间为100，采用双缓冲需要花费的时间为100*10+50+60=1110。","multi":0,"questionType":1,"answer":"B","chooseItem":["796237365097025537"],"itemList":[{"id":"796237365084442625","questionId":"796237364203638785","content":" 1000","answer":0,"chooseValue":"A"},{"id":"796237365097025537","questionId":"796237364203638785","content":" 1110","answer":1,"chooseValue":"B"},{"id":"796237365105414145","questionId":"796237364203638785","content":" 1650","answer":0,"chooseValue":"C"},{"id":"796237365113802753","questionId":"796237364203638785","content":" 2100","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237536170102785","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>进程P1、P2、P3、P4、P5的前趋图如下。<br><img alt=\"\" width=\"251\" height=\"121\" src=\"https://image.chaiding.com/ruankao/dcad4c53686ebf71e5472406e60b01fa.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制进程并发执行的过程，则需要相应于进程执行过程设置5个信号量S1、S2、S3、S4和S5,且信号量初值都等于零。下图中a处应填写（50） ：b和c、 d和e处应分别填写（51）,f、g和h应分别填写（52）。<br><img width=\"542\" height=\"193\" alt=\"\" src=\"https://image.chaiding.com/ruankao/193653ae2d78d74c97fe6a212bd1d348.jpg?x-oss-process=style/ruankaodaren\">","analyze":"根据前驱图，P2进程开始运行前必须等待P1进程的通知，需要用P(S1)操作测试P1进程是否运行完，P2进程运行结束需要利用V(S3)操作通知P4进程。同理根据前驱图P3进程开始运行前必须等待P1进程的通知，需要用P(S2)操作测试P1进程是否运行完，P3进程运行结朿需要利用V(S4)操作通知P4进程。","multi":0,"questionType":1,"answer":"D","chooseItem":["796237537101238273"],"itemList":[{"id":"796237537050906625","questionId":"796237536170102785","content":" P(S1)和P(S2)、V(S3)和V(S4)","answer":0,"chooseValue":"A"},{"id":"796237537067683841","questionId":"796237536170102785","content":" P(S1)和P(S2)、P(S3)和P(S4)","answer":0,"chooseValue":"B"},{"id":"796237537080266753","questionId":"796237536170102785","content":" V(S1)和V(S2)、P(S3)和P(S4)","answer":0,"chooseValue":"C"},{"id":"796237537101238273","questionId":"796237536170102785","content":" P(S1)和V(S3)、P(S2)和V(S4)","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237514946924545","title":"<p><strong>请作答第<span style=\"color: red\">3</span>个空。</strong></p>进程P1、P2、P3、P4、P5和P6的前趋图如下所示：<br><img alt=\"\" width=\"193\" height=\"67\" src=\"https://image.chaiding.com/ruankao/393eb0cf6f8376c2426c97819763dbd0.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制这6个进程的同步与互斥的程序如下，那么程序中的空①和空②处应分别为（48）；空③和空④处应分别为（49）；空⑤和空⑥处应分别为（50）。<br><img alt=\"\" width=\"509\" height=\"230\" src=\"https://image.chaiding.com/ruankao/f251ce998e590656f65fb68aa7def97c.jpg?x-oss-process=style/ruankaodaren\">","analyze":"根据前驱图P4、P5进程执行完都需要通知P6进程，P6进程运行前执行了P(S6)和P(S7)，而P5进程执行完后执行了V(S7)，故P4进程应该执行V(S6)，即空⑤应填V(S6)。又因为P5进程开始运行前必须等待P3进程的通知，需要用P(S5)操作测试P3进程是否运行完。故空⑥应填写P(S5)。<br>根据上述分析，用PV操作控制这6个进程的同步与互斥的程序如下：u2003<br><img alt=\"\" width=\"523\" height=\"259\" src=\"https://image.chaiding.com/ruankao/5966dfe13cc998820170eaf7e0300879.jpg?x-oss-process=style/ruankaodaren\">","multi":0,"questionType":1,"answer":"D","chooseItem":["796237515899031553"],"itemList":[{"id":"796237515857088513","questionId":"796237514946924545","content":" P(S6)和V(S5)","answer":0,"chooseValue":"A"},{"id":"796237515869671425","questionId":"796237514946924545","content":" P(S6)和P(S5)","answer":0,"chooseValue":"B"},{"id":"796237515886448641","questionId":"796237514946924545","content":" V(S5)和V(S6)","answer":0,"chooseValue":"C"},{"id":"796237515899031553","questionId":"796237514946924545","content":" V(S6)和P(S5)","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237443710865409","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>某文件管理系统在磁盘上建立了位示图（bitmap)，记录磁盘的使用情况。假设计算机系统的字长为32位，磁盘的容量为200GB,物理块的大小为1MB,那么位示图的大小有(49)个字，需要占用（50）物理块。","analyze":"根据题意系统中字长为32位，可记录32个物理块的使用情况。又因为磁盘的容量为200GB，物理块的大小为1MB,那么该磁盘有200*1024=204800个物理块，位示图的大小为204800/32=6400个字。","multi":0,"questionType":1,"answer":"D","chooseItem":["796237444805578753"],"itemList":[{"id":"796237444734275585","questionId":"796237443710865409","content":" 600","answer":0,"chooseValue":"A"},{"id":"796237444759441409","questionId":"796237443710865409","content":" 1200","answer":0,"chooseValue":"B"},{"id":"796237444784607233","questionId":"796237443710865409","content":" 3200","answer":0,"chooseValue":"C"},{"id":"796237444805578753","questionId":"796237443710865409","content":" 6400","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237358532939777","title":"<p><strong>请作答第<span style=\"color: red\">3</span>个空。</strong></p>假设某银行拥有的资金数是10,现在有4个用户a、b、c、d,各自需要的最大资金数分别是4、5、6、7。若在图a的情况下，用户a和b又各申请1个资金，则银行分配 后用户a、b、c、d尚需的资金数分别为（46）；假设用户a已经还清所有借款，其情况如图b所示，那么银行的可用资金数为 （47）。若在图b的情况下，银行为用户b、c、d各分配资金数1、1、2，则银行分配后用户b、c、d已用资金数分别为（48）。<br><img alt=\"\" width=\"566\" height=\"174\" src=\"https://image.chaiding.com/ruankao/2edc9cdd442f692b5d91ad8ce6a8439e.jpg?x-oss-process=style/ruankaodaren\">","analyze":"在图b的情况下，系统为用户b、c、d已分配资金数为3、2、1，系统又为用户b、c、d分配资金数为1、1、2,则系统分配后用户b、c、d已用资金数分别为4、3、3。这样导致系统的可用资金为0,故系统状态是不安全的。","multi":0,"questionType":1,"answer":"D","chooseItem":["796237359443103745"],"itemList":[{"id":"796237359413743617","questionId":"796237358532939777","content":" 4、 3、 2, 尚需资金数分别为1、 3、5,故系统状态是安全的","answer":0,"chooseValue":"A"},{"id":"796237359422132225","questionId":"796237358532939777","content":" 4、 3、 3, 尚需资金数分别为1、 3、4,故系统状态是安全的","answer":0,"chooseValue":"B"},{"id":"796237359434715137","questionId":"796237358532939777","content":" 4、 3、 2, 尚需资金数分别为1、 3、5,故系统状态是不安全的","answer":0,"chooseValue":"C"},{"id":"796237359443103745","questionId":"796237358532939777","content":" 4、 3、 3, 尚需资金数分别为1、 3、4,故系统状态是不安全的","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237440288313345","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>某文件管理系统在磁盘上建立了位示图（bitmap),来记录磁盘的使用情况。若磁盘上的物理块依次编号为：0、1、2、…，系统中字长为16位，每一位对应文件存储器上的一个物理块，取值0和1分别表示空闲和占用，如下图所示。<br><img alt=\"\" width=\"205\" height=\"51\" src=\"https://image.chaiding.com/ruankao/68d2c0a8cceab62229dde3969d9d5176.jpg?x-oss-process=style/ruankaodaren\"><br>假设将2057号物理块分配给某文件，那么该物理块的使用情况在位示图中的第(48)个字中描述：系统应该将该字的（49）。","analyze":"本题考査的是操作系统文件管理方面的基本知识。<br>文件管理系统是在外存上建立一张位示图（bitmap),记录文件存储器的使用情况。每一位对应文件存储器上的一个物理块，取值0和1分别表示空闲和占用，如下图所示。<br><img alt=\"\" width=\"375\" height=\"196\" src=\"https://image.chaiding.com/ruankao/73fae142f1f9124bdbe381d12d97fed9.jpg?x-oss-process=style/ruankaodaren\"><br>由于系统中字长为16位，因此每个字可以表示16个物理块的使用情况。又因为文件存储器上的物理块依次编号为0、1、2、…，所以2057号物理块应该在位示图的第129个字中描述。又因为第129个字中的第0位对应2048号物理块，第1位对应2049号物理块，第2位对应2050号物理块，第3位对应2051号物理块，第4位对应2052号物理块，第5位对应2053号物理块，第6位对应2054号物理块，第7位对应2055号物理块，第8位对应2056号物理块，第9位对应2057号物理块，所以系统应该将该字的第9位置“1”，即将编号为9的位置“1”。","multi":0,"questionType":1,"answer":"B","chooseItem":["796237441206865921"],"itemList":[{"id":"796237441194283009","questionId":"796237440288313345","content":" 编号为9的位置“0”","answer":0,"chooseValue":"A"},{"id":"796237441206865921","questionId":"796237440288313345","content":" 编号为9的位置“1”","answer":1,"chooseValue":"B"},{"id":"796237441219448833","questionId":"796237440288313345","content":" 编号为8的位置“0”","answer":0,"chooseValue":"C"},{"id":"796237441236226049","questionId":"796237440288313345","content":" 编号为8的位置“1”","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237437150973953","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>某文件管理系统在磁盘上建立了位示图（bitmap),来记录磁盘的使用情况。若磁盘上的物理块依次编号为：0、1、2、…，系统中字长为16位，每一位对应文件存储器上的一个物理块，取值0和1分别表示空闲和占用，如下图所示。<br><img alt=\"\" width=\"205\" height=\"51\" src=\"https://image.chaiding.com/ruankao/68bf51ed1b9a9b4db48381aff0751f52.jpg?x-oss-process=style/ruankaodaren\"><br>假设将2057号物理块分配给某文件，那么该物理块的使用情况在位示图中的第(48)个字中描述：系统应该将该字的（49）。","analyze":"本题考査的是操作系统文件管理方面的基本知识。<br>文件管理系统是在外存上建立一张位示图（bitmap),记录文件存储器的使用情况。每一位对应文件存储器上的一个物理块，取值0和1分别表示空闲和占用，如下图所示。<br><img alt=\"\" width=\"375\" height=\"196\" src=\"https://image.chaiding.com/ruankao/8f3a56a9dd81a3a541162cc9b42aefa9.jpg?x-oss-process=style/ruankaodaren\"><br>由于系统中字长为16位，因此每个字可以表示16个物理块的使用情况。又因为文件存储器上的物理块依次编号为0、1、2、…，所以2057号物理块应该在位示图的第129个字中描述。又因为第129个字中的第0位对应2048号物理块，第1位对应2049号物理块，第2位对应2050号物理块，第3位对应2051号物理块，第4位对应2052号物理块，第5位对应2053号物理块，第6位对应2054号物理块，第7位对应2055号物理块，第8位对应2056号物理块，第9位对应2057号物理块，所以系统应该将该字的第9位置“1”，即将编号为9的位置“1”。","multi":0,"questionType":1,"answer":"B","chooseItem":["796237438275047425"],"itemList":[{"id":"796237438258270209","questionId":"796237437150973953","content":" 128","answer":0,"chooseValue":"A"},{"id":"796237438275047425","questionId":"796237437150973953","content":" 129","answer":1,"chooseValue":"B"},{"id":"796237438291824641","questionId":"796237437150973953","content":" 130","answer":0,"chooseValue":"C"},{"id":"796237438308601857","questionId":"796237437150973953","content":" 131","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237347212513281","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>假设某系统采用非抢占式优先级调度算法，若该系统有两个优先级相同的进程P1和P2,各进程的程序段如下所示，若信号量S1和S2的初值都为0。进程P1和P2并发执行后a、b和c的结果分别为：a= (50) ，b= (51) ，c= (52)。<br><img alt=\"\" width=\"296\" height=\"190\" src=\"https://image.chaiding.com/ruankao/72d8aaca291817c89b9d6e66fae51800.jpg?x-oss-process=style/ruankaodaren\">","analyze":"本题考查操作系统PV操作方面的基础知识。<br>假设P1先运行，系统执行“a:=1; a:=a+2”后a=3;执行“V (S1)”后，S1=1, P继续执行；执行“c:=a+l”后，c=4;执行“P (S2)”后，S2=-1，P1被阻塞。<br>此时轮到P2运行，系统执行“b:=1; b:=b+2”后b=3;执行“P (S1)”后，S1=0,P2继续执行；执行“b:=a+b”后，b=6;执行“V (S2)”后，S2=0，唤醒P1, P2继续执行；执行“c:=b+c”后，c=10，P2运行结束。<br>此时轮到P1运行，系统执行“a:=a+c”后，a=13, P1运行结束。<br>综上分析可见，进程P1和P2并发执行后a、b和c的结果分别为：a=13, b=6, c=10。","multi":0,"questionType":1,"answer":"B","chooseItem":["796237348105900033"],"itemList":[{"id":"796237348089122817","questionId":"796237347212513281","content":" 4","answer":0,"chooseValue":"A"},{"id":"796237348105900033","questionId":"796237347212513281","content":" 6","answer":1,"chooseValue":"B"},{"id":"796237348118482945","questionId":"796237347212513281","content":" 9","answer":0,"chooseValue":"C"},{"id":"796237348135260161","questionId":"796237347212513281","content":" 10","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237339176226817","title":"以下关于程序访问局部性原理的叙述，错误的是（18）。","analyze":"本题考查存储系统知识。<br>程序访问的局部性原理包含两方面的含义：一是时间局部性，指程序在最近的未来要用到的信息可能是现在正在使用的信息；二是空间局部性，指最近的未来要用到的信息与现在正在使用的信息很可能在空间上是相邻的或相近的，这是因为程序中大多数指令是顺序存放且顺序执行的，数据一般也是聚簇存储在一起的。<br>程序访问局部性原理是存储层次得以构成和管理的主要依据。根据该原理，可以把空间位置相临近的信息作为一 “块”放到容量最小的第一级存储器Ml中，在最近未来的一段时间内多次连续访存很可能都在Ml的同一 “块”中，从而使整个存储系统的访问速度接近于Ml的速度。","multi":0,"questionType":1,"answer":"D","chooseItem":["796237340119945217"],"itemList":[{"id":"796237340078002177","questionId":"796237339176226817","content":" 程序访问具有时间局部性，即最近将要用的信息很可能是正在使用的信息","answer":0,"chooseValue":"A"},{"id":"796237340090585089","questionId":"796237339176226817","content":" 程序访问具有空间局部性，即最近将要用的信息很可能与正在使用的信息在存储空间上是相邻的","answer":0,"chooseValue":"B"},{"id":"796237340107362305","questionId":"796237339176226817","content":" 程序访问局部性是构成层次结构的存储系统的主要依据","answer":0,"chooseValue":"C"},{"id":"796237340119945217","questionId":"796237339176226817","content":" 程序访问局部性是确定存储系统的性能指标（命中率、平均访问时间、访问效率等）的主要依据","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237489885958145","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>若某文件系统的目录结构如下图所示，假设用户要访问文件f.java，且当前工作目录为Program,则该文件的全文件名为（46），绝对路径和相对路径分别为（47）。<br><img alt=\"\" width=\"352\" height=\"202\" src=\"https://image.chaiding.com/ruankao/22e8a9a27e1b07c9edced9a619992753.jpg?x-oss-process=style/ruankaodaren\">","analyze":"路径名是指操作系统査找文件所经过的目录名以及目录名之间的分隔符构成的。在Windows系统中文件的全文件名为路径名+文件名。<br>按查找文件的起点不同可以将路径分为：绝对路径和相对路径。从根目录开始的路径称为绝对路径；从用户当前工作目录开始的路径称为相对路径，相对路径是随着当前工作目录的变化而改变的。","multi":0,"questionType":1,"answer":"D","chooseItem":["796237490884202497"],"itemList":[{"id":"796237490821287937","questionId":"796237489885958145","content":" f.java","answer":0,"chooseValue":"A"},{"id":"796237490846453761","questionId":"796237489885958145","content":" Java-prog\\f.java","answer":0,"chooseValue":"B"},{"id":"796237490863230977","questionId":"796237489885958145","content":" Program\\Java-prog\\f.java","answer":0,"chooseValue":"C"},{"id":"796237490884202497","questionId":"796237489885958145","content":" \\Program\\Java-prog\\f.java","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237468780220417","title":"某系统采用请求页式存储管理方案，假设某进程有6个页面，系统给该进程分配了4个存储块，其页面变换表如下表所示，表中的状态位等于1和0分别表示页面在内存或不在内存。当该进程访问的第3号页面不在内存时，应该淘汰表中页面号为（49）的页面。<br><img alt=\"\" width=\"502\" height=\"189\" src=\"https://image.chaiding.com/ruankao/34ae9d7c5991d01d8a006232c3f61a7a.jpg?x-oss-process=style/ruankaodaren\">","analyze":"本题考查操作系统存储管理方面的基础知识。<br>请求页式存储管理方案中，当访问的页面不在内存时需要置换页面，正确的置换页面的原则如下表，即最先置换访问位和修改位为00,第二访问位和修改位为01，第三访问位和修改位为10,最后才置换访问位和修改位为11。 因此本题当该进程访问的页面3不在内存时，应该淘汰表中页号为4的页面。<br><img alt=\"\" width=\"558\" height=\"117\" src=\"https://image.chaiding.com/ruankao/b9d811430403129f2d04222b830f9d57.jpg?x-oss-process=style/ruankaodaren\">","multi":0,"questionType":1,"answer":"C","chooseItem":["796237469837185025"],"itemList":[{"id":"796237469799436289","questionId":"796237468780220417","content":" 0","answer":0,"chooseValue":"A"},{"id":"796237469816213505","questionId":"796237468780220417","content":" 2","answer":0,"chooseValue":"B"},{"id":"796237469837185025","questionId":"796237468780220417","content":" 4","answer":1,"chooseValue":"C"},{"id":"796237469858156545","questionId":"796237468780220417","content":" 5","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237533305393153","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>进程P1、P2、P3、P4、P5的前趋图如下。<br><img alt=\"\" width=\"251\" height=\"121\" src=\"https://image.chaiding.com/ruankao/da36cb113cac227b12beb003bf467ba5.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制进程并发执行的过程，则需要相应于进程执行过程设置5个信号量S1、S2、S3、S4和S5,且信号量初值都等于零。下图中a处应填写（50） ：b和c、 d和e处应分别填写（51）,f、g和h应分别填写（52）。<br><img width=\"542\" height=\"193\" alt=\"\" src=\"https://image.chaiding.com/ruankao/cb513969f268367bed7fee71e79a07a4.jpg?x-oss-process=style/ruankaodaren\">","analyze":"根据前驱图，P1进程运行结束需要利用V操作分别通知P2和P3进程，所以用V(S1)操作通知P2进程，用V(S2)操作通知P3进程。","multi":0,"questionType":1,"answer":"B","chooseItem":["796237534236528641"],"itemList":[{"id":"796237534219751425","questionId":"796237533305393153","content":" P(S1)和P(S2)","answer":0,"chooseValue":"A"},{"id":"796237534236528641","questionId":"796237533305393153","content":" V(S1)和V(S2)","answer":1,"chooseValue":"B"},{"id":"796237534253305857","questionId":"796237533305393153","content":" P(S1)和V(S2)","answer":0,"chooseValue":"C"},{"id":"796237534270083073","questionId":"796237533305393153","content":" P(S2)和V(S1)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237426031874049","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>微内核体系结构的操作系统（OS)实现时的基本思想是（51），其结构图如下所示，图中①②③④应填写（52）。","analyze":"微内核体系结构如下图所示，其基本思想是把操作系统中与硬件直接相关的部分抽取出来作为一个公共层，称之为硬件抽象层（HAL)。这个硬件抽象层其实就是“种虚 拟机，它向所有基于该层的其他层通过API接口提供一系列标准服务。在微内核中只保留了处理机调度、存储管理和消息通讯等少数几个组成部分，将传统操作系统内核中的 一些组成部分放到内核之外来实现。如传统操作系统中的文件管理系统、进程管理、设备管理、虚拟内存和网络等内核功能都放在内核外作为一个独立的子系统来实现。因此， 操作系统的大部分代码只要在一种统一的硬件体系结构上进行设计就可以了。","multi":0,"questionType":1,"answer":"C","chooseItem":["796237427009146881"],"itemList":[{"id":"796237426963009537","questionId":"796237426031874049","content":" 内核完成OS所有功能并在用户态下运行","answer":0,"chooseValue":"A"},{"id":"796237426983981057","questionId":"796237426031874049","content":" 内核完成OS所有功能并在核心态下运行","answer":0,"chooseValue":"B"},{"id":"796237427009146881","questionId":"796237426031874049","content":" 内核只完成OS最基本的功能并在核心态下运行，其他功能运行在用户态","answer":1,"chooseValue":"C"},{"id":"796237427030118401","questionId":"796237426031874049","content":" 内核只完成OS,最基本的功能并在用户态下运行，其他功能运行在核心态","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237336072441857","title":"以下关于域本地组的叙述中，正确的是（9）.","analyze":"本题考查Windows Server 2003活动目录中用户组的概念。<br>在Windows Server 2003的活动目录中，用户分为全局组（Global Groups)、域本地组（Domain Local Groups)和通用组（Universal Groups)。其中全局组成员来自于同一域的用户账户和全局组，可以访问域中的任何资源：域本地组成员来自森林中任何域中的用户账户、全局组和通用组以及本域中的域本地组，只能访问本地域中的资源；通用组成员来自森林中任何域中的用户账户、全局组和其他的通用组，可以授予多个域中的访问权限。","multi":0,"questionType":1,"answer":"A","chooseItem":["796237337066491905"],"itemList":[{"id":"796237337066491905","questionId":"796237336072441857","content":" 成员可来自森林中的任何域，仅可访问本地域内的资源","answer":1,"chooseValue":"A"},{"id":"796237337091657729","questionId":"796237336072441857","content":" 成员可来自森林中的任何域，可访问任何域中的资源","answer":0,"chooseValue":"B"},{"id":"796237337112629249","questionId":"796237336072441857","content":" 成员仅可来自本地域，仅可访问本地域内的资源","answer":0,"chooseValue":"C"},{"id":"796237337133600769","questionId":"796237336072441857","content":" 成员仅可来自本地域，可访问任何域中的资源","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237461096255489","title":"某文件系统釆用链式存储管理方式并应用记录的成组与分解技术，且磁盘块的大小为4096字节。若文件license.doc由7个逻辑记录组成，每个逻辑记录的大小为2048字节，并依次存放在58、89、96和101号磁盘块上，那么要存取文件的第12288逻辑字节处的信息，应访问(49)号磁盘块。","analyze":"逻辑字节也称为相对字节，是从0开始计算的，而[(12288+1)/4096]4,所以第12288逻辑字节处的信息，应访问101应号磁盘块。","multi":0,"questionType":1,"answer":"D","chooseItem":["796237462182580225"],"itemList":[{"id":"796237462136442881","questionId":"796237461096255489","content":" 58","answer":0,"chooseValue":"A"},{"id":"796237462153220097","questionId":"796237461096255489","content":" 89","answer":0,"chooseValue":"B"},{"id":"796237462165803009","questionId":"796237461096255489","content":" 96","answer":0,"chooseValue":"C"},{"id":"796237462182580225","questionId":"796237461096255489","content":" 101","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237551307345921","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>进程Pl、P2、P3、P4、P5的前趋关系图如下所示：<br><img alt=\"\" width=\"300\" height=\"135\" src=\"https://image.chaiding.com/ruankao/ca1ca6350c18fb8550e812c443a0094f.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制这5个进程的同步与互斥，程序如下:<br><img alt=\"\" src=\"https://image.chaiding.com/ruankao/0befefc625cfec10060bedcefb8008ec.jpg?x-oss-process=style/ruankaodaren\" height=\"199\" width=\"369\"><br>程序中空a和空b处应分别为（48）；空c和空d处应分别为（49）；空e和空f处应分别为（50） 。","analyze":"根据前驱图，P2进程需要等待P1进程的通知，故需要利用P(S1)操作测试P1进程是否运行完，P2进程运行结束需要利用V操作分别通知P3和P4进程，所以用V(S2)操作通知P3进程，用V(S3)操作通知P4进程。<br>根据前驱图，P3进程开始运行前必须等待P2和P4进程的通知，需要用P(S2)操作测试P2进程是否运行完，用P(S4)操作测试P4进程是否运行完，P2进程运行结束需要利用V(S5)操作通知P5进程。<br>根据前驱图，P4进程开始运行前必须等待P2进程的通知，需要用P(S3)操作测试P2进程是否运行完，故空e应填写P(S3)。P4进程运行结束需要利用V操作通知P3和P5进程，故空g应填写V(S4)V(S6)。","multi":0,"questionType":1,"answer":"C","chooseItem":["796237552246870017"],"itemList":[{"id":"796237552217509889","questionId":"796237551307345921","content":" V(S2)V(S4)和V(S5)","answer":0,"chooseValue":"A"},{"id":"796237552234287105","questionId":"796237551307345921","content":" P(S2)V(S4)和V(S5)","answer":0,"chooseValue":"B"},{"id":"796237552246870017","questionId":"796237551307345921","content":" P(S2)P(S4)和V(S5)","answer":1,"chooseValue":"C"},{"id":"796237552263647233","questionId":"796237551307345921","content":" P(S2)V(S4)和P(S5)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237328103264257","title":"—般来讲，在并行处理系统中，将程序的模块划分得越小，(14)。","analyze":"本题考查并行处理系统的基本概念。<br>一般来说，将程序的模块划分得越小，程序模块间的数据相关性越大，通信的开销也越大。线程是程序中一个单一的顺序控制流程，模块越小就需要越多的线程，如果有大量的线程，会由于相互切换而影响性能，更多的线程也需要更多的内存空间，即开销更大。","multi":0,"questionType":1,"answer":"A","chooseItem":["796237329009233921"],"itemList":[{"id":"796237329009233921","questionId":"796237328103264257","content":" 程序模块间的数据相关性越大，线程创建和通信的开销越大","answer":1,"chooseValue":"A"},{"id":"796237329021816833","questionId":"796237328103264257","content":" 程序模块间的数据相关性越小，线程创建和通信的开销越大","answer":0,"chooseValue":"B"},{"id":"796237329034399745","questionId":"796237328103264257","content":" 程序模块间的数据相关性越小，线程创建和通信的开销越小","answer":0,"chooseValue":"C"},{"id":"796237329046982657","questionId":"796237328103264257","content":" 程序模块间的数据相关性越大，线程创建和通信的开销越小","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237474400587777","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>某风险投资公司拥有的总资金数为25，分期为项目P1、P2、P3、P4投资，各项目投资情况如下表所示。公司的可用资金数为（50）。若P1和P3分别申请资金数1和2，则公司资金管理处（51）。<br><img alt=\"\" width=\"510\" height=\"144\" src=\"https://image.chaiding.com/ruankao/ec3e982cc46fe1f4db6431c01d833ebf.jpg?x-oss-process=style/ruankaodaren\">","analyze":"对于试题（50），因为企业的总资金数是25,企业资金管理处为项目P1、P2、P3、P4已投资的资金总数=5+5+6+7=23,故可用资金数为2。","multi":0,"questionType":1,"answer":"C","chooseItem":["796237475310751745"],"itemList":[{"id":"796237475285585921","questionId":"796237474400587777","content":" 0","answer":0,"chooseValue":"A"},{"id":"796237475298168833","questionId":"796237474400587777","content":" 1","answer":0,"chooseValue":"B"},{"id":"796237475310751745","questionId":"796237474400587777","content":" 2","answer":1,"chooseValue":"C"},{"id":"796237475323334657","questionId":"796237474400587777","content":" 3","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237508928098305","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>进程P1、P2、P3、P4、P5和P6的前趋图如下所示：<br><img alt=\"\" width=\"193\" height=\"67\" src=\"https://image.chaiding.com/ruankao/7f132c428ba38c73b4b20425da32ab3e.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制这6个进程的同步与互斥的程序如下，那么程序中的空①和空②处应分别为（48）；空③和空④处应分别为（49）；空⑤和空⑥处应分别为（50）。<br><img alt=\"\" width=\"509\" height=\"230\" src=\"https://image.chaiding.com/ruankao/a5b5c1b282f3a478476ae5e9228d6e03.jpg?x-oss-process=style/ruankaodaren\">","analyze":"根据前驱图，P2进程需要等待P1进程的通知，故需要利用P(S1)操作测试P1进程是否运行完，所以空①应填P(S1)，P2进程运行结束需要利用V操作分别通知P3、P4进程，由于P3进程执行前已经用P(S2)，所以空②应填V(S2)。","multi":0,"questionType":1,"answer":"B","chooseItem":["796237510056366081"],"itemList":[{"id":"796237510018617345","questionId":"796237508928098305","content":" V(S1)和P(S2)","answer":0,"chooseValue":"A"},{"id":"796237510056366081","questionId":"796237508928098305","content":" P(S1)和V(S2)","answer":1,"chooseValue":"B"},{"id":"796237510085726209","questionId":"796237508928098305","content":" V(S1)和V(S2)","answer":0,"chooseValue":"C"},{"id":"796237510102503425","questionId":"796237508928098305","content":" V(S2)和P(S1)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237539059978241","title":"<p><strong>请作答第<span style=\"color: red\">3</span>个空。</strong></p>进程P1、P2、P3、P4、P5的前趋图如下。<br><img alt=\"\" width=\"251\" height=\"121\" src=\"https://image.chaiding.com/ruankao/7f73fe68771c783a459a0f6409e2e108.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制进程并发执行的过程，则需要相应于进程执行过程设置5个信号量S1、S2、S3、S4和S5,且信号量初值都等于零。下图中a处应填写（50） ：b和c、 d和e处应分别填写（51）,f、g和h应分别填写（52）。<br><img width=\"542\" height=\"193\" alt=\"\" src=\"https://image.chaiding.com/ruankao/2e13437d0a1a77bfcc026157373d0cde.jpg?x-oss-process=style/ruankaodaren\">","analyze":"根据前驱图，P4进程开始运行前必须等待P2和P3进程的通知，需要用P(S3)和P(S4)操作分别测试P2和P3进程是否运行完，故空f应填写P(S3)P(S4)。P4进程运行结束需要利用V(S5)操作通知P5进程，故空g应填写V(S5)。根据前驱图，P5进程开始运行前必须等待P4进程的通知，需要用P(S5)操作测试P4进程是否运行完，故空h应填写P(S5)。","multi":0,"questionType":1,"answer":"C","chooseItem":["796237540003696641"],"itemList":[{"id":"796237539974336513","questionId":"796237539059978241","content":" P(S3)V(S4)、V(S5)和P(S5)","answer":0,"chooseValue":"A"},{"id":"796237539991113729","questionId":"796237539059978241","content":" V(S3)V(S4)、P(S5)和V(S5)","answer":0,"chooseValue":"B"},{"id":"796237540003696641","questionId":"796237539059978241","content":" P(S3)P(S4)、V(S5)和P(S5)","answer":1,"chooseValue":"C"},{"id":"796237540016279553","questionId":"796237539059978241","content":" V(S3)P(S4)、P(S5)和V(S5)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237410311622657","title":"嵌入式系统初始化过程主要有3个环节，按照自底向上、从硬件到软件的次序依次为（）。","analyze":"本题考查嵌入式系统方面的基础知识。<br>嵌入式系统初始化过程可以分为3个主要环节，按照自底向上、从硬件到软件的次序依次为：片级初始化、板级初始化和系统级初始化。<br>①片级初始化：完成嵌入式微处理器的初始化，包括设置嵌入式微处理器的核心寄存器和控制寄存器、嵌入式微处理器核心工作模式和嵌入式微处理器的局部总线模式等。片级初始化把嵌入式微处理器从上电时的默认状态逐步设置成系统所要求的工作状态。这是一个纯硬件的初始化过程。<br>②板级初始化：完成嵌入式微处理器以外的其他硬件设备的初始化。另外，还需设置某些软件的数据结构和参数，为随后的系统级初始化和应用程序的运行建立硬件和软件环境。这是一个同时包含软硬件两部分在内的初始化过程。<br>③系统初始化：该初始化过程以软件初始化为主，主要进行操作系统的初始化。BSP将对嵌入式微处理器的控制权转交给嵌入式操作系统，由操作系统完成余下的初始化操作，包含加载和初始化与硬件无关的设备驱动程序，建立系统内存区，加载并初始化其他系统软件模块，如网络系统、文件系统等。最后，操作系统创建应用程序环境，并将控制权交给应用程序的入口。","multi":0,"questionType":1,"answer":"B","chooseItem":["796237411376975873"],"itemList":[{"id":"796237411360198657","questionId":"796237410311622657","content":" 片级初始化→系统级初始化→板级初始化","answer":0,"chooseValue":"A"},{"id":"796237411376975873","questionId":"796237410311622657","content":" 片级初始化→板级初始化→系统级初始化","answer":1,"chooseValue":"B"},{"id":"796237411389558785","questionId":"796237410311622657","content":" 系统级初始化→板级初始化→片级初始化","answer":0,"chooseValue":"C"},{"id":"796237411402141697","questionId":"796237410311622657","content":" 系统级初始化→片级初始化→板级初始化","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237548404887553","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>进程Pl、P2、P3、P4、P5的前趋关系图如下所示：<br><img alt=\"\" width=\"300\" height=\"135\" src=\"https://image.chaiding.com/ruankao/f80ff7a26b2464a688b862dbeee3a947.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制这5个进程的同步与互斥，程序如下:<br><img alt=\"\" height=\"199\" width=\"369\" src=\"https://image.chaiding.com/ruankao/596239905131cc0dc7597afbe7004393.jpg?x-oss-process=style/ruankaodaren\"><br>程序中空a和空b处应分别为（48）；空c和空d处应分别为（49）；空e和空f处应分别为（50） 。","analyze":"根据前驱图，P2进程需要等待P1进程的通知，故需要利用P(S1)操作测试P1进程是否运行完，P2进程运行结束需要利用V操作分别通知P3和P4进程，所以用V(S2)操作通知P3进程，用V(S3)操作通知P4进程。<br>根据前驱图，P3进程开始运行前必须等待P2和P4进程的通知，需要用P(S2)操作测试P2进程是否运行完，用P(S4)操作测试P4进程是否运行完，P2进程运行结束需要利用V(S5)操作通知P5进程。<br>根据前驱图，P4进程开始运行前必须等待P2进程的通知，需要用P(S3)操作测试P2进程是否运行完，故空e应填写P(S3)。P4进程运行结束需要利用V操作通知P3和P5进程，故空g应填写V(S4)V(S6)。","multi":0,"questionType":1,"answer":"B","chooseItem":["796237549348605953"],"itemList":[{"id":"796237549331828737","questionId":"796237548404887553","content":" V(S1)和V(S2)V(S3)","answer":0,"chooseValue":"A"},{"id":"796237549348605953","questionId":"796237548404887553","content":" P(SI)和V(S2)V(S3)","answer":1,"chooseValue":"B"},{"id":"796237549361188865","questionId":"796237548404887553","content":" P(SI)和P(S2)V(S3)","answer":0,"chooseValue":"C"},{"id":"796237549377966081","questionId":"796237548404887553","content":" P(SI)和P(S2)P(S3)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237557196148737","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>进程Pl、P2、P3、P4、P5的前趋图如下：<br><img alt=\"\" width=\"249\" height=\"125\" src=\"https://image.chaiding.com/ruankao/b93625fe3be83a99015641c885a2723e.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制进程并发执行的过程，则需要设置4个信号量S1、S2、S3和S4，且信号量初值都等于零。下图中a和b应分别填写（50），c和d应分别填写（51），e和f应分别填写（52）。<br><img alt=\"\" width=\"432\" height=\"154\" src=\"https://image.chaiding.com/ruankao/dadb699b0c6c95144ab5d2f9104be2dc.jpg?x-oss-process=style/ruankaodaren\">","analyze":"本题考查的是操作系统进程管理中PV操作方面的基本知识。<br>根据题意，进程P3等待P1、P2的结果，因此，当P1、P2执行完毕需要使用V操作通知P3，即a处填V(S1),b处填V(S2)。","multi":0,"questionType":1,"answer":"C","chooseItem":["796237558093729793"],"itemList":[{"id":"796237558068563969","questionId":"796237557196148737","content":" P(S1)和P(S2)","answer":0,"chooseValue":"A"},{"id":"796237558081146881","questionId":"796237557196148737","content":" P(S1)和V(S2)","answer":0,"chooseValue":"B"},{"id":"796237558093729793","questionId":"796237557196148737","content":" V(S1)和V(S2)","answer":1,"chooseValue":"C"},{"id":"796237558106312705","questionId":"796237557196148737","content":" V(S1)和P(S2)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237355689201665","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>假设某银行拥有的资金数是10,现在有4个用户a、b、c、d,各自需要的最大资金数分别是4、5、6、7。若在图a的情况下，用户a和b又各申请1个资金，则银行分配 后用户a、b、c、d尚需的资金数分别为（46）；假设用户a已经还清所有借款，其情况如图b所示，那么银行的可用资金数为 （47）。若在图b的情况下，银行为用户b、c、d各分配资金数1、1、2，则银行分配后用户b、c、d已用资金数分别为（48）。<br><img alt=\"\" width=\"566\" height=\"174\" src=\"https://image.chaiding.com/ruankao/a2132a399862b3a9aab0a7368defc40a.jpg?x-oss-process=style/ruankaodaren\">","analyze":"银行家的总资金数是10,为用户b、c、d分配了 3、2、1,故可用资金数为4。","multi":0,"questionType":1,"answer":"A","chooseItem":["796237356586782721"],"itemList":[{"id":"796237356586782721","questionId":"796237355689201665","content":" 4","answer":1,"chooseValue":"A"},{"id":"796237356607754241","questionId":"796237355689201665","content":" 5","answer":0,"chooseValue":"B"},{"id":"796237356632920065","questionId":"796237355689201665","content":" 6","answer":0,"chooseValue":"C"},{"id":"796237356658085889","questionId":"796237355689201665","content":" 7","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237446739152897","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>某文件管理系统在磁盘上建立了位示图（bitmap)，记录磁盘的使用情况。假设计算机系统的字长为32位，磁盘的容量为200GB,物理块的大小为1MB,那么位示图的大小有(49)个字，需要占用（50）物理块。","analyze":"位示图占6400个字，即6400X4=25600字节， 故需要占用25600/1024=25个物理块。","multi":0,"questionType":1,"answer":"B","chooseItem":["796237447624151041"],"itemList":[{"id":"796237447611568129","questionId":"796237446739152897","content":" 20","answer":0,"chooseValue":"A"},{"id":"796237447624151041","questionId":"796237446739152897","content":" 25","answer":1,"chooseValue":"B"},{"id":"796237447636733953","questionId":"796237446739152897","content":" 30","answer":0,"chooseValue":"C"},{"id":"796237447649316865","questionId":"796237446739152897","content":" 35","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237361343123457","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>假设磁盘块与缓冲区大小相同，每个盘块读入缓冲区的时间为100<img alt=\"\" src=\"https://image.chaiding.com/ruankao/8e8c2d2283156428de0c529fba370909.jpg?x-oss-process=style/ruankaodaren\" height=\"17\" width=\"15\">，缓冲区送入用户区的时间是60<img alt=\"\" width=\"14\" height=\"15\" src=\"https://image.chaiding.com/ruankao/1da1b351cd933d51c1a676d5f2e6e482.jpg?x-oss-process=style/ruankaodaren\">，系统对每个磁盘块数据的处理时间为50<img alt=\"\" width=\"14\" height=\"15\" src=\"https://image.chaiding.com/ruankao/efa250bd0df9eac8d665d6b3e5e4a09e.jpg?x-oss-process=style/ruankaodaren\">。若用户需要将大小为10个磁盘块的Filel文件逐块从磁盘读入缓冲区，并送用户区进行处理，那么采用单缓冲需要花费的时间为（51） <img alt=\"\" width=\"14\" height=\"15\" src=\"https://image.chaiding.com/ruankao/4d18d5dd387295743d79516fabf419f9.jpg?x-oss-process=style/ruankaodaren\">；采用双缓冲需要花费的时间为（52）<img alt=\"\" width=\"14\" height=\"15\" src=\"https://image.chaiding.com/ruankao/bb99864ad27a238c69a75a00b3301a1a.jpg?x-oss-process=style/ruankaodaren\">。","analyze":"在块设备输入时，假定从磁盘把一块数据输入到缓冲区的时间为T，缓冲区中的数据传送到用户工作区的时间为M，而系统处理（计算）的时间为C，如图（a）所示：<br><img alt=\"\" src=\"https://image.chaiding.com/ruankao/f081a02b4f99fd2616a0de981ecef222.jpg?x-oss-process=style/ruankaodaren\" height=\"101\" width=\"398\"><br>当第一块数据送入用户工作区后，缓冲区是空闲的可以传送第二块数据。这样第一块数据的处理C1与第二块数据的输入T2是可以并行的，依次类推，如图（b）所示。 系统对每一块数据的处理时间为：Max(C，T)+M。因为，当T>C时，处理时间为M+T; 当T<C时，处理时间为M+C。本题每一块数据的处理时间为100+60=160, Filel文件的处理时间为160*10+50。<br><img alt=\"\" src=\"https://image.chaiding.com/ruankao/762e2ea29efe2845cadacf8b69b5fddb.jpg?x-oss-process=style/ruankaodaren\" height=\"91\" width=\"388\"><br><br>双缓冲工作方式基本方法是在设备输入时，先将数据输入到缓冲区1，装满后便转向缓冲区2。此时系统可以从缓冲区1中提取数据传送到用户区，最后由系统对数据进行处理，如下图（c）所示：<br><img alt=\"\" width=\"400\" height=\"111\" src=\"https://image.chaiding.com/ruankao/32e2ede2d9d0aec6ee0c9e46a436f44f.jpg?x-oss-process=style/ruankaodaren\"><br>双缓冲可以实现对缓冲区中数据的输入T和提取M,与CPU的计算C,三者并行工作，如下图（d）所示。所以双缓冲进一步加快了I/O的速度，提高了设备的利用率。在双缓冲时，系统处理一块数据的时间可以粗略地认为是Max(C，T)。如果C<T,可使块设备连续输入；如果C>T,则可使系统不必等待设备输入。本题每一块数据的处理时间为100，采用双缓冲需要花费的时间为100*10+50+60=1110。","multi":0,"questionType":1,"answer":"C","chooseItem":["796237362249093121"],"itemList":[{"id":"796237362223927297","questionId":"796237361343123457","content":" 1000","answer":0,"chooseValue":"A"},{"id":"796237362236510209","questionId":"796237361343123457","content":" 1110","answer":0,"chooseValue":"B"},{"id":"796237362249093121","questionId":"796237361343123457","content":" 1650","answer":1,"chooseValue":"C"},{"id":"796237362265870337","questionId":"796237361343123457","content":" 2100","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237524602212353","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>进程P1、P2、P3、P4、P5和P6的前趋图如下所示：<br><img alt=\"\" width=\"313\" height=\"133\" src=\"https://image.chaiding.com/ruankao/dece68ccc4a254236963c62e619d8acf.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制这6个进程的同步与互斥的程序如下，那么程序中的空a、空b和空c处应分别为（46）；空d和空e处应分别为（47）；空f和空g处应分别为（48）。<br><img alt=\"\" width=\"589\" height=\"255\" src=\"https://image.chaiding.com/ruankao/0213f91567a64bac552cdabdd36a35c1.jpg?x-oss-process=style/ruankaodaren\">","analyze":"对于试题（46），根据前驱图P2进程需要等待P1进程的通知，故需要利用P (S1) 操作测试P1进程是否运行完，P2进程运行结束需要利用V操作分别通知P4进程，所以空a应填V (S2)用以通知P4进程可以执行：前驱图P3进程开始运行前必须等待P1 进程的通知，需要用P操作测试P1进程是否运行完，所以空b应填P (S2)操作测试P1进程是否运行完；P3进程运行结束需要利用V (S4) V (S5)操作通知P4和P5进程可以开始运行，故空c应填V (S4) V (S5)。<br>根据上述分析，用PV操作控制这6个进程的同步与互斥的程序如下：<br><img alt=\"\" width=\"625\" height=\"312\" src=\"https://image.chaiding.com/ruankao/563692e95471bef4f7d026140521e834.jpg?x-oss-process=style/ruankaodaren\">","multi":0,"questionType":1,"answer":"A","chooseItem":["796237525499793409"],"itemList":[{"id":"796237525499793409","questionId":"796237524602212353","content":" V(S3)、P(S2)和V(S4)V(S5)","answer":1,"chooseValue":"A"},{"id":"796237525512376321","questionId":"796237524602212353","content":" P(S3)、P(S2)和V(S4)V(S5)","answer":0,"chooseValue":"B"},{"id":"796237525520764929","questionId":"796237524602212353","content":" V(S2)、P(S3)和P(S4)P(S3)","answer":0,"chooseValue":"C"},{"id":"796237525533347841","questionId":"796237524602212353","content":" V(S2)、V(S3)和P(S3)P(S4)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237352853852161","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>假设某银行拥有的资金数是10,现在有4个用户a、b、c、d,各自需要的最大资金数分别是4、5、6、7。若在图a的情况下，用户a和b又各申请1个资金，则银行分配 后用户a、b、c、d尚需的资金数分别为（46）；假设用户a已经还清所有借款，其情况如图b所示，那么银行的可用资金数为 （47）。若在图b的情况下，银行为用户b、c、d各分配资金数1、1、2，则银行分配后用户b、c、d已用资金数分别为（48）。<br><img alt=\"\" width=\"566\" height=\"174\" src=\"https://image.chaiding.com/ruankao/2d5261ba83d3fcb4131082bb6de5e90d.jpg?x-oss-process=style/ruankaodaren\">","analyze":"在图a的情况下，用户a和b各申请1个资金， 则系统分配后用户a、b、c、d的已用资金数分别为2、3、2、1，可用资金数为2,故尚 需的资金数分别为2、2、4、6。由于可用资金数为2,能保证a或b运行结束。假定a运行结束释放资源后，可用资金数为4,能保证b或c运行结束。同理，b运行结束释放资源后，可用资金数为7,能保证c或d运行结束。最终c运行结束，释放资源能使d获得所需资金运行结束，故系统状态是安全的。","multi":0,"questionType":1,"answer":"C","chooseItem":["796237353772404737"],"itemList":[{"id":"796237353743044609","questionId":"796237352853852161","content":" 2、 2、 3、 3, 可用资金数为0, 故系统状态是不安全的","answer":0,"chooseValue":"A"},{"id":"796237353755627521","questionId":"796237352853852161","content":" 3、 3、 3、 5, 可用资金数为0, 故系统状态是不安全的","answer":0,"chooseValue":"B"},{"id":"796237353772404737","questionId":"796237352853852161","content":" 2、 2、 4、 6, 可用资金数为2, 故系统状态是安全的","answer":1,"chooseValue":"C"},{"id":"796237353780793345","questionId":"796237352853852161","content":" 3、 3、 3、 5, 可用资金数为2, 故系统状态是安全的","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237512069632001","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>进程P1、P2、P3、P4、P5和P6的前趋图如下所示：<br><img alt=\"\" width=\"193\" height=\"67\" src=\"https://image.chaiding.com/ruankao/b157fb4483da229ba8a24470a99f6b9e.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制这6个进程的同步与互斥的程序如下，那么程序中的空①和空②处应分别为（48）；空③和空④处应分别为（49）；空⑤和空⑥处应分别为（50）。<br><img alt=\"\" width=\"509\" height=\"230\" src=\"https://image.chaiding.com/ruankao/96872f1f2c3cae67321f6182dbcb5fa8.jpg?x-oss-process=style/ruankaodaren\">","analyze":"根据前驱图，P3进程运行结束需要利用两个V操作分别通知P4、P5进程，故空③应为两个V操作；又由于P4执行前需要等待进程P2、P3的结果，需要2个P操作，而P4进程的程序中执行前只有1个P操作，故空④应为1个P操作。","multi":0,"questionType":1,"answer":"A","chooseItem":["796237512958824449"],"itemList":[{"id":"796237512958824449","questionId":"796237512069632001","content":" V(S4)V(S5)和P(S3)","answer":1,"chooseValue":"A"},{"id":"796237512975601665","questionId":"796237512069632001","content":" P(S4)P(S5)和V(S3)","answer":0,"chooseValue":"B"},{"id":"796237512992378881","questionId":"796237512069632001","content":" V(S3)V(S4)和V(S5)","answer":0,"chooseValue":"C"},{"id":"796237513004961793","questionId":"796237512069632001","content":" P(S3)V(S4)和P(S3)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237495812509697","title":"若读取（47）的某个磁盘块进行修改，将结果写回磁盘前系统崩溃，则对系统的影响相对较大。","analyze":"本题考查的是应试者对操作系统文件管理可靠性方面的基础知识的掌握程度。<br>影响文件系统可靠性因素之一是文件系统的一致性问题。很多文件系统是先读取磁盘块到主存，在主存进行修改，修改完毕再写回磁盘。但如读取某磁盘块，修改后再将信息写回磁盘前系统崩溃，则文件系统就可能会出现不一致性状态。如果这些未被写回的磁盘块是索引节点块、目录块或空闲块，特别是系统目录文件，那么对系统的影响相对较大，且后果也是不堪设想的。通常解决方案是采用文件系统的一致性检査，一致性检查包括块的一致性检查和文件的一致性检查。","multi":0,"questionType":1,"answer":"C","chooseItem":["796237496798171137"],"itemList":[{"id":"796237496773005313","questionId":"796237495812509697","content":" 用户文件","answer":0,"chooseValue":"A"},{"id":"796237496785588225","questionId":"796237495812509697","content":" 空闲表","answer":0,"chooseValue":"B"},{"id":"796237496798171137","questionId":"796237495812509697","content":" 系统目录文件","answer":1,"chooseValue":"C"},{"id":"796237496814948353","questionId":"796237495812509697","content":" 用户目录文件","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237530457460737","title":"<p><strong>请作答第<span style=\"color: red\">3</span>个空。</strong></p>进程P1、P2、P3、P4、P5和P6的前趋图如下所示：<br><img alt=\"\" width=\"313\" height=\"133\" src=\"https://image.chaiding.com/ruankao/fa2bdc3d368afad06efcdc3bb2836103.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制这6个进程的同步与互斥的程序如下，那么程序中的空a、空b和空c处应分别为（46）；空d和空e处应分别为（47）；空f和空g处应分别为（48）。<br><img alt=\"\" width=\"589\" height=\"255\" src=\"https://image.chaiding.com/ruankao/9020c74ef04eebdf9508121bd51f7a50.jpg?x-oss-process=style/ruankaodaren\">","analyze":"对于试题（48），根据前驱图P5进程开始运行前必须等待P3进程的通知，需要用P (S5)操作测试P3进程是否运行完，故空f应填写P (S5)：P5进程运行结束需要利用V操作通知P6进程，故空g应填写V(S7)。","multi":0,"questionType":1,"answer":"C","chooseItem":["796237531367624705"],"itemList":[{"id":"796237531338264577","questionId":"796237530457460737","content":" V(S5)和V(S7)","answer":0,"chooseValue":"A"},{"id":"796237531355041793","questionId":"796237530457460737","content":" P(5)和P(S7)","answer":0,"chooseValue":"B"},{"id":"796237531367624705","questionId":"796237530457460737","content":" P(S5)和V(S7)","answer":1,"chooseValue":"C"},{"id":"796237531380207617","questionId":"796237530457460737","content":" V(S5)和P(S7)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796237565907718145","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>进程P有6个页面，页号分别为0~5，页面大小为4K，页面变换表如下所示。表中状态位等于1和0分别表示页面在内存和不在内存。假设系统给进程P分配了4个存储块，进程P要访问的逻辑地址为十六进制1165H,那么该地址经过变换后，其物理地址应为十六进制（46）：如果进程P要访问的页面4不在内存，那么应该淘汰页号为（47）的页面。<br><img alt=\"\" width=\"317\" height=\"149\" src=\"https://image.chaiding.com/ruankao/9d3326cd568fedbb366f7d43cd4add18.jpg?x-oss-process=style/ruankaodaren\">","analyze":"本题考查操作系统存储管理方面的基础知识。<br>根据题意，页面大小为4K,逻辑地址为十六进制1165H, 其页号为1,页内地址为165H，查页表后可知页帧号（物理块号）为3,该地址经过变换后，其物理地址应为页帧号3拼上页内地址165H，即十六进制3165H。<br>根据题意，页面变换表中状态位等于1和0分别表示页面在内存或不在内存，所以0、1、2和5号页面在内存。当访问的页面4不在内存时，系统应该首先淘汰未被访问的页面，因为根据程序的局部性原理，最近未被访问的页面下次被访问的概率更小；如果页面最近都被访问过，应该先淘汰未修改过的页面，因为未修改过的页面内存与辅存一致，故淘汰时无需写回辅存，使系统页面置换代价小。经上述分析，0、1和2号页面都是最近被访问过的，但5号页面最近未被访问过，故应该淘汰5号页面。","multi":0,"questionType":1,"answer":"B","chooseItem":["796237566834659329"],"itemList":[{"id":"796237566822076417","questionId":"796237565907718145","content":" 165H","answer":0,"chooseValue":"A"},{"id":"796237566834659329","questionId":"796237565907718145","content":" 3165H","answer":1,"chooseValue":"B"},{"id":"796237566847242241","questionId":"796237565907718145","content":" 5165H","answer":0,"chooseValue":"C"},{"id":"796237566864019457","questionId":"796237565907718145","content":" 6165H","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234571128524801","title":"多核操作系统的设计方法不同于单核操作系统，一般要突破（ ）等方面的关键技术。","analyze":"随着计算机芯片的快速发展，多核处理器己成主流CPU,操作系统应适应处理器的发展，因此多核操作系统已成为操作系统主流。多核操作系统的设计方法与单核相比存在很大差异，除了考虑单核基本功能设计外，还应突破与多核相关技术。主要包括了以下几点：<br> ①核结构：操作系统的核心功能与CPU的内核结构密切相关，多核结构的不同影响着内核的多核工作方式。<br> ②Cache设计:多核操作系统内核设计方法与多核Cache的设计相关，解决多核Cache一致性问题与单核相比要复杂得多。<br> ③核间通信：核间通信技术是多核操作系统必须解决的关键技术，核间通信的优劣直接影响着多核操作系统的效能。<br> ④任务调度：任务调度是操作系统的核心功能，其调度策略的选择与单核或多核结构紧密相关，多核的任务调度需要考虑核间负载平衡问题以及任务同步问题。<br> ⑤中断处理：中断处理是多核结构中需要共享的资源，与单核设计不同的是在多核情况下需要考虑中断与核的依赖关系。<br> ⑥存储器墙设计：存储器墙设计是多核硬件结构设计中必须解决的空间隔离技术，不属于操作系统设计范畴。<br> ⑦同步互斥：多核环境下的共享资源同步互斥，是多核操作系统必须解决的关键技术，在多核环境下共享资源同步互斥也是保障系统安全的有效方法。<br> ⑧总体设计：多核的总体设计主要考虑系统架构设计，是一种软硬件的整体考虑，虽然要提出对软件的需求，但并不是多核操作系统最需要突破的技术。<br> 综上所述，选项A中的总体设计不在多核操作系统设计范畴；选项B中的可靠性设计、安全性设计是单核和多核都要突破的技术，因此不在多核操作系统突破技术范畴；选项C中的存储器墙设计不在多核操作系统设计范畴。","multi":0,"questionType":1,"answer":"D","chooseItem":["796234572118380545"],"itemList":[{"id":"796234572047077377","questionId":"796234571128524801","content":" 总线设计、Cache设计、核间通信、任务调度、中断处理、同步互斥","answer":0,"chooseValue":"A"},{"id":"796234572072243201","questionId":"796234571128524801","content":" 核结构、Cache设计、核间通信、可靠性设计、安全性设计、同步互斥","answer":0,"chooseValue":"B"},{"id":"796234572101603329","questionId":"796234571128524801","content":" 核结构、Cache设计、核间通信、任务调度、中断处理、存储器墙设计","answer":0,"chooseValue":"C"},{"id":"796234572118380545","questionId":"796234571128524801","content":" 核结构、Cache设计、核间通信、任务调度、中断处理、同步互斥","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234574106480641","title":"多核CPU环境下进程的调度算法一般有全局队列调度和局部队列调度两种。（ ）属于全局队列调度的特征。","analyze":"在多核环境下，任务调度是操作系统设计的关键技术，通常采用全局队列调度和局部队列调度两种方式。但是两种调度队列的作用不同，主要体现在以下几点。<br> 全局队列调度：<br> 操作系统维护一个全局的任务等待队列。<br> 当系统中有一个CPU核心空闲时，操作系统从全局任务等待队列中选取就绪任务开始在此核心上执行。 <br> 这种方法的优点是提高了CPU核心利用率。<br> 局部队列调度：<br> 操作系统为每个CPU内核维护一个局部的任务等待队列。<br> 当系统中有一个CPU核心空闲时,操作系统便从该核心的任务等待队列中选取适当的任务执行。<br> 这种方法的优点是任务基本上无需在多个CPU核心间切换，有利于提高CPU核心局部Cache命中率。<br> 目前大多数多核CPU操作系统采用的是基于全局队列的任务调度算法。<br> 因此，操作系统维护一个任务等待队列属于全局队列调度的特征。","multi":0,"questionType":1,"answer":"B","chooseItem":["796234575041810433"],"itemList":[{"id":"796234575025033217","questionId":"796234574106480641","content":" 操作系统为每个CPU维护一个任务等待队列","answer":0,"chooseValue":"A"},{"id":"796234575041810433","questionId":"796234574106480641","content":" 操作系统维护一个任务等待队列","answer":1,"chooseValue":"B"},{"id":"796234575058587649","questionId":"796234574106480641","content":" 任务基本上无需在多个CPU核心间切换，有利于提高Cache命中率","answer":0,"chooseValue":"C"},{"id":"796234575071170561","questionId":"796234574106480641","content":" 当系统中有一个CPU核心空闲时，操作系统便从该核心的任务等待队列中选取适当的任务执行","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796233849569824769","title":"嵌入式实时系统存在许多调度算法。如果调度程序根据任务的紧急程度确定该任务的优先级，任务紧急程度高，被赋予的优先级就高，可被优先执行。这种调度算法称之为（）。","analyze":"这种调度算法根据任务的紧急程度确定任务的优先级，任务紧急程度高被赋予的优先级就高，可被优先执行。这种算法称之为抢占式优先级调度（Preemptive Priority Scheduling, PPS）算法，因为在运行时会根据任务的优先级抢占正在执行的低优先级任务。而最早截止时间优先（Earliest Deadline First, EDF）算法、最低松弛度优先（Least Laxity First, LLF）算法和单调速率调度（Rate Monotonic Scheduling, RMS）算法则是根据任务的截止时间、松弛度和周期等特性来确定调度策略的。因此，选项D是正确答案。","multi":0,"questionType":1,"answer":"D","chooseItem":["796233850765201409"],"itemList":[{"id":"796233850689703937","questionId":"796233849569824769","content":" 最早截止时间优先（Earliest Deadline First, EDF）算法","answer":0,"chooseValue":"A"},{"id":"796233850714869761","questionId":"796233849569824769","content":" 最低松弛度优先（Least Laxity First, LLF）算法","answer":0,"chooseValue":"B"},{"id":"796233850740035585","questionId":"796233849569824769","content":" 单调速率调度（Rate Monotonic Scheduling, RMS）算法","answer":0,"chooseValue":"C"},{"id":"796233850765201409","questionId":"796233849569824769","content":" 抢占式优先级调度（Preemptive Priority Scheduling, PPS）算法","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796233837217599489","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>嵌入式系统已被广泛应用到各行各业。嵌入式系统是一个内置于设备中，对设备的各种传感器进行管理与控制的系统。通常，根据系统对时间的敏感程度可将嵌入式系统划分为（14）两种，而实时系统又可分为强实时（Hard Real-Time）系统和弱实时（Weak Real-Time）系统；如果从安全性要求看，嵌入式系统还可分为（15）。","analyze":"简单地说，实时系统可以看成对外部事件能够及时响应的系统。这种系统最重要的特征是时间性，也就是实时性，实时系统的正确性不仅依赖于系统计算的逻辑结果，还依赖于产生这些结果的时间。在现实世界中，并非所有的嵌入式系统都具有实时特性，所有的实时系统也不--定都是嵌入式的。但这两种系统并不互相排斥，兼有这两种系统特性的系统称为实时嵌入式系统。","multi":0,"questionType":1,"answer":"A","chooseItem":["796233838345867265"],"itemList":[{"id":"796233838345867265","questionId":"796233837217599489","content":" 嵌入式系统和嵌入式实时系统","answer":1,"chooseValue":"A"},{"id":"796233838375227393","questionId":"796233837217599489","content":" 控制系统和业务系统","answer":0,"chooseValue":"B"},{"id":"796233838400393217","questionId":"796233837217599489","content":" 安全攸关系统和非安全攸关系统","answer":0,"chooseValue":"C"},{"id":"796233838421364737","questionId":"796233837217599489","content":" CPS系统和非CPS系统","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796233840363327489","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>嵌入式系统已被广泛应用到各行各业。嵌入式系统是一个内置于设备中，对设备的各种传感器进行管理与控制的系统。通常，根据系统对时间的敏感程度可将嵌入式系统划分为（14）两种，而实时系统又可分为强实时（Hard Real-Time）系统和弱实时（Weak Real-Time）系统；如果从安全性要求看，嵌入式系统还可分为（15）。","analyze":"简单地说，实时系统可以看成对外部事件能够及时响应的系统。这种系统最重要的特征是时间性，也就是实时性，实时系统的正确性不仅依赖于系统计算的逻辑结果，还依赖于产生这些结果的时间。在现实世界中，并非所有的嵌入式系统都具有实时特性，所有的实时系统也不--定都是嵌入式的。但这两种系统并不互相排斥，兼有这两种系统特性的系统称为实时嵌入式系统。","multi":0,"questionType":1,"answer":"C","chooseItem":["796233841424486401"],"itemList":[{"id":"796233841344794625","questionId":"796233840363327489","content":" 高可靠系统和高安全系统","answer":0,"chooseValue":"A"},{"id":"796233841395126273","questionId":"796233840363327489","content":" 实时系统和强实时系统","answer":0,"chooseValue":"B"},{"id":"796233841424486401","questionId":"796233840363327489","content":" 安全攸关系统和非安全攸关系统","answer":1,"chooseValue":"C"},{"id":"796233841453846529","questionId":"796233840363327489","content":" 网络系统和分布式系统","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796233843395809281","title":"嵌入式软件开发方法与传统软件开发方法存在较大差异，（）的说法对嵌入式软件开发而言是错误的。","analyze":"由于嵌入式系统存储容量有限，所以嵌入式系统的软件代码都比较精炼，代码规模比较小。","multi":0,"questionType":1,"answer":"D","chooseItem":["796233844423413761"],"itemList":[{"id":"796233844314361857","questionId":"796233843395809281","content":" 嵌入式软件开发的结果通常需要固化在目标系统的储存器或处理器内部储存器资源中","answer":0,"chooseValue":"A"},{"id":"796233844347916289","questionId":"796233843395809281","content":" 嵌入式软件的开发一般需要专门的开发工具、目标系统和测试设备","answer":0,"chooseValue":"B"},{"id":"796233844385665025","questionId":"796233843395809281","content":" 嵌入式软件对安全性和可靠性的要求较高","answer":0,"chooseValue":"C"},{"id":"796233844423413761","questionId":"796233843395809281","content":" 嵌入式软件开发不用考虑代码的规模","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796235139691597825","title":"假设某文件系统的文件索引表有i-addr[0]，i-addr[1] ，...，i-addr[7]共8个地址项，每个地址项大小为4字节，其中5个地址项（i-addr[0]~i-addr[4] )为直接地址索引，2个地址项 (i-addr[5]~i-addr[6])是一级间接地址索引，1个地址项 (i-addr[7] )是二级间接地址索引，磁盘索引块和磁盘数据块大小均为1KB。若要访问文件的逻辑块号分别为5和518，则系统应分别采用（ ）。","analyze":"本题考查考生操作系统文件管理方面的基础知识。<br>根据题意，磁盘索引块为1KB字节，每个地址项大小为4字节，故每个磁盘索引块可存放1024/4=256个物理块地址。又因为文件索引节点中有8个地址项，其中5个地址项为直接地址索引，这意味着逻辑块号为0~4的为直接地址索引；第5、6地址项是一级间接地址索引，这意味着第5地址项指出的物理决中存放逻辑块号为5~260的物理块号，第6地址项指出的物理块中存放逻辑块号为261~516 的物理块号；第7地址项是二级间接地址索引，该地址项指出的物理块存放了256个间接索引表的地址，这256个间接索引表存放逻辑块号为517~66052的物理块号。<br>经上分析不难得出，若要访问文件的逻辑块号为5和518,则系统应采用一级间接地址索引和二级间接地址索引。","multi":0,"questionType":1,"answer":"C","chooseItem":["796235140769533953"],"itemList":[{"id":"796235140731785217","questionId":"796235139691597825","content":" 直接地址索引和一级间接地址索引","answer":0,"chooseValue":"A"},{"id":"796235140748562433","questionId":"796235139691597825","content":" 直接地址索引和二级间接地址索引","answer":0,"chooseValue":"B"},{"id":"796235140769533953","questionId":"796235139691597825","content":" 一级间接地址索引和二级间接地址索引","answer":1,"chooseValue":"C"},{"id":"796235140786311169","questionId":"796235139691597825","content":" 二级间接地址索引和一级间接地址索引","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234419181473793","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>在进程资源有向图中，圆圈表示进程，方框表示资源，方框内的小圆数表示资源数。当有向边（或称请求边）由进程指向资源时，表示申请一个资源；当有向边（或称分配边）由资源指向进程时，表示获得一个资源。假设系统中存三个进程P1、P2和P3,两种资源R1、 R2,且R1的资源数等于3, R2的资源数等于3。如果进程资源图如图(a)和图b)所示， 那么图（a）中(46):图（b）中(47)。<br> <img width=\"468\" height=\"157\" src=\"https://image.chaiding.com/ruankao/a4da46a8b52ec5e0b01aa5fbe81ac2e1.jpg?x-oss-process=style/ruankaodaren\" alt=\"\">","analyze":"根据题中所述“R2的资源数等于3”，从图（a）可见已经给进程P1、P2、P3各分配1个R2资源，因此R2的可用资源数等于0。进程P1、P2、P3又分别再申请1个R2,该申请得不到满足，故进程P1、P2、P3都是阻塞节点。可见进程资源图（a）不可以化简，是死锁的。<br> 图(b)中P3只有分配边无请求边，故是非阻塞节点。P1是阻塞节点，因为它请求再获得一个R2资源，而R2的可用资源数等于0,其申请得不到满足，所以P1阻塞。P2是阻塞节点，分析同P1。又因为P3是非阻塞节点，可以运行完毕，释放其占有的1个R1资源和1个R2资源，然后P1申请1个R2资源可以得到满足，这样可以使得P1变为非阻塞节点，得到所需资源运行完毕，释放其占有资源，使得P2变为非阻塞节点，运行完毕。故进程资源图（b）可以化简，是非死锁的。","multi":0,"questionType":1,"answer":"A","chooseItem":["796234420095832065"],"itemList":[{"id":"796234420095832065","questionId":"796234419181473793","content":" P1、P2、P3都是阻塞节点，该图不可以化简，是死锁的","answer":1,"chooseValue":"A"},{"id":"796234420129386497","questionId":"796234419181473793","content":" P1、P2、P3都是非阻塞节点，该图可以化简，是非死锁的","answer":0,"chooseValue":"B"},{"id":"796234420158746625","questionId":"796234419181473793","content":" Pl、P2是非阻塞节点，P3是阻塞节点，该图不可以化简，是死锁的","answer":0,"chooseValue":"C"},{"id":"796234420192301057","questionId":"796234419181473793","content":" P3是非阻塞节点，P1、P3是阻塞节点，该图可以化简，是非死锁的","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234664166576129","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>前趋图是一个有向无环图，记为→=｛（Pi,Pj）pi完成时间先于Pj开始时间｝。假设系统中进P=｛P1，P2，P3，P4，P5，P6，P7，P8｝，且进程的前趋图如下：<br> <img alt=\"\" src=\"https://image.chaiding.com/ruankao/8eead6c26b73a713f0a5841c026b1322.jpg?x-oss-process=style/ruankaodaren\" width=\"386\" height=\"182\" title=\"\" align=\"\"><br> 那么，该前趋图可记为（46），图中（47）。","analyze":"本题考查操作系统基本概念。<br> 前趋图（Precedence Graph)是一个有向无循环图，记为DAG(Directed Acyclic Graph),用于描述进程之间执行的前后关系。图中的每个结点可用于描述一个程序段或进程，乃至一条语句；结点间的有向边则用于表示两个结点之间存在的偏序（Partial Order,亦称偏序关系）或前趋关系（Precedence Relation) “→”。<br> 对于题中所示的前趋图，存在着前趋关系：P1→P2，P1→P4，P2→P3，P2→P5，P3→P4，P3→P6，P4→P7，P5→P6，P6→P8，P7→P6。可记为：<br> P={P1，P2，P3，P4，P5，P6，P7，P8}<br> →={(P1，P2)，(P1，P4)，(P2，P3)，(P2，P5)，(P3，P4)，(P3，P6)，(P4，P7)，（P5，P6)，(P6，P8)，(P7，P6)}<br> 从以上分析可知存在着10个前趋关系。另外在前趋图中，把没有前趋的结点称为初始结点(Initial Node),故P<sub>1</sub>为初始结点。把没有后继的结点称为终止结点(Final Node), 故P<sub>8</sub>为终止结点。","multi":0,"questionType":1,"answer":"B","chooseItem":["796234665240317953"],"itemList":[{"id":"796234665215152129","questionId":"796234664166576129","content":" →={(P1，P2),(P1，P3),(P1,P4),(P2,P5),(P3,P2),(P3.P4).（P3，P6).(P4,P7),(P5,P8)","answer":0,"chooseValue":"A"},{"id":"796234665240317953","questionId":"796234664166576129","content":" →={(P1，P2)，(P1，P4)，(P2,P3),(P2,P5)，(P3,P4)，(P3,P6),(P4,P7)，(P5,P6)，(P6,P8),(P7,P6)}","answer":1,"chooseValue":"B"},{"id":"796234665278066689","questionId":"796234664166576129","content":" →={(P1,P2),(P1，P4)，(P2,P5)，(P3,P2)，(P3,P4)，(P3,P6),(P4,P6)，(P4,p7),(p6，p8)，(p7,P8)}","answer":0,"chooseValue":"C"},{"id":"796234665303232513","questionId":"796234664166576129","content":" →={(P1,P2)，(P1，P3)，(P2,P4),(P2,P5)，(P3,P2),(P3 ,P4)，(P3,P5)，(P4，P7)，(P6，P8)，(P7，P8)}","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796235376162263041","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>某文件管理系统在磁盘上建立了位示图(bitmap)，记录磁盘的使用情况。若磁盘上物理块的编号依次为：0、1、2、…；系统中的字长为32位，字的编号依次为：0、1、2、…，字中的一位对应文件存储器上的一个物理块，取值0和1分别表示空闲和占用，如下图所示。<br><img alt=\"\" width=\"335\" height=\"203\" src=\"https://image.chaiding.com/ruankao/f3e0bd410096e5e03f296feca405160c.jpg?x-oss-process=style/ruankaodaren\"><br>假设操作系统将2053号物理块分配给某文件，那么该物理块的使用情况在位示图中编号为（46）的字中描述；系统应该将（47）。","analyze":"本题考查操作系统内存管理方面的基本知识。<br>文件管理系统是在外存上建立一张位示图（bitmap），来记录文件存储器的使用情况。每一位对应文件存储器上的一个物理块，取值0和1分别表示空闲和占用。<br>由于系统中字长为32位，所以每个字可以表示32个物理块的使用情况。又因为文件存储器上的物理块依次编号为：0，1，2，…，因此2056号物理块应该在位示图的第64个字中描述。又因为第64个字中的第0位对应编号为2048的物理块，第1位对应2049号物理块，第2位对应2050号物理块，第3位对应2051号物理块，第4位对应2052号物理块，第5位对应2053号物理块，所以系统应该将该字的第5位置“1”。","multi":0,"questionType":1,"answer":"C","chooseItem":["796235377101787137"],"itemList":[{"id":"796235377076621313","questionId":"796235376162263041","content":" 32","answer":0,"chooseValue":"A"},{"id":"796235377089204225","questionId":"796235376162263041","content":" 33","answer":0,"chooseValue":"B"},{"id":"796235377101787137","questionId":"796235376162263041","content":" 64","answer":1,"chooseValue":"C"},{"id":"796235377114370049","questionId":"796235376162263041","content":" 65","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234900712738817","title":"采用微内核结构的操作系统设计的基本思想是内核只完成操作系统最基本的功能并在核心态下运行，其他功能运行在用户态，其结构图如下所示。图中空（a）、（b）、（c）和（d）应分别选择如下所示①~④中的哪一项? （ ）。<br>①核心态 ②用户态 ③文件和存储器服务器 ④进程调度及进程间通信<br><img alt=\"\" width=\"399\" height=\"70\" src=\"https://image.chaiding.com/ruankao/f8e651fb1567cd66b41371815294085e.jpg?x-oss-process=style/ruankaodaren\">","analyze":"微内核体系结构的操作系统（OS)实现时的基本思想是内核只完成OS最基本的功能并在核心状态下运行，其他功能运行在用户态，其结构图如下所示。<br><img alt=\"\" width=\"537\" height=\"103\" src=\"https://image.chaiding.com/ruankao/ecf3e88e2c4c43940098e9bc50f7d5d3.jpg?x-oss-process=style/ruankaodaren\">","multi":0,"questionType":1,"answer":"C","chooseItem":["796234901723566081"],"itemList":[{"id":"796234901660651521","questionId":"796234900712738817","content":" ①、②、③和④","answer":0,"chooseValue":"A"},{"id":"796234901698400257","questionId":"796234900712738817","content":" ④、③、②和①","answer":0,"chooseValue":"B"},{"id":"796234901723566081","questionId":"796234900712738817","content":" ③、④、②和①","answer":1,"chooseValue":"C"},{"id":"796234901757120513","questionId":"796234900712738817","content":" ③、①、④和②","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796233939831246849","title":"某系统中有5个并发进程竞争资源R。假设每个进程都需要3个R，那么最少需要有（）个R，才能保证系统不会发生死锁。","analyze":"至少需要资源数=并发进程数*(每个进程需要资源数-1)+1=5*(3-1)+1=11","multi":0,"questionType":1,"answer":"B","chooseItem":["796233940787548161"],"itemList":[{"id":"796233940753993729","questionId":"796233939831246849","content":" 10","answer":0,"chooseValue":"A"},{"id":"796233940787548161","questionId":"796233939831246849","content":" 11","answer":1,"chooseValue":"B"},{"id":"796233940816908289","questionId":"796233939831246849","content":" 12","answer":0,"chooseValue":"C"},{"id":"796233940833685505","questionId":"796233939831246849","content":" 13","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234667312304129","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>前趋图是一个有向无环图，记为→=｛（Pi,Pj）pi完成时间先于Pj开始时间｝。假设系统中进P=｛P1，P2，P3，P4，P5，P6，P7，P8｝，且进程的前趋图如下：<br> <img alt=\"\" src=\"https://image.chaiding.com/ruankao/60e1597f9fbe84d4896880af7fd81238.jpg?x-oss-process=style/ruankaodaren\" width=\"386\" height=\"182\" title=\"\" align=\"\"><br> 那么，该前趋图可记为（46），图中（47）。","analyze":"本题考查操作系统基本概念。<br> 前趋图（Precedence Graph)是一个有向无循环图，记为DAG(Directed Acyclic Graph),用于描述进程之间执行的前后关系。图中的每个结点可用于描述一个程序段或进程，乃至一条语句；结点间的有向边则用于表示两个结点之间存在的偏序（Partial Order,亦称偏序关系）或前趋关系（Precedence Relation) “→”。<br> 对于题中所示的前趋图，存在着前趋关系：P1→P2，P1→P4，P2→P3，P2→P5，P3→P4，P3→P6，P4→P7，P5→P6，P6→P8，P7→P6。可记为：<br> P={P1，P2，P3，P4，P5，P6，P7，P8}<br> →={(P1，P2)，(P1，P4)，(P2，P3)，(P2，P5)，(P3，P4)，(P3，P6)，(P4，P7)，（P5，P6)，(P6，P8)，(P7，P6)}<br> 从以上分析可知存在着10个前趋关系。另外在前趋图中，把没有前趋的结点称为初始结点(Initial Node),故P<sub>1</sub>为初始结点。把没有后继的结点称为终止结点(Final Node), 故P<sub>8</sub>为终止结点。","multi":0,"questionType":1,"answer":"D","chooseItem":["796234668369268737"],"itemList":[{"id":"796234668281188353","questionId":"796234667312304129","content":" 存在着10个前趋关系，P1为初始结点，P2P4为终止结点","answer":0,"chooseValue":"A"},{"id":"796234668314742785","questionId":"796234667312304129","content":" 存在着2个前趋关系，P6为初始结点，P2P4为终止结点","answer":0,"chooseValue":"B"},{"id":"796234668348297217","questionId":"796234667312304129","content":" 存在着9个前趋关系，P6为初始结点，P8为终止结点","answer":0,"chooseValue":"C"},{"id":"796234668369268737","questionId":"796234667312304129","content":" 存在着10个前趋关系，P1,为初始结点，P8为终止结点","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796235142761828353","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>在一个单CPU的计算机系统中，采用可剥夺式(也称抢占式)优先级的进程调度方案，且所有任务可以并行使用I/O设备。下表列出了三个任务T1、T2 、T3 的优先级、独立运行时占用CPU和I/O设备的时间。如果操作系统的开销忽略不计，这三个任务从同时启动到全部结束的总时间为（47）ms ，CPU的空闲时间共有（48）ms 。<br><img alt=\"\" width=\"458\" height=\"97\" src=\"https://image.chaiding.com/ruankao/81ec8d55c4f73e4d395832eefec3e20a.jpg?x-oss-process=style/ruankaodaren\">","analyze":"本题考查的是操作系统进程调度方面的知识。<br>根据题意可知，三个任务的优先级T1>T2>T3,进程调度的过程如下图所示。分析如下：<br><img alt=\"\" width=\"556\" height=\"147\" src=\"https://image.chaiding.com/ruankao/a16f52742134f5e9a2d748d4a2d7fab2.jpg?x-oss-process=style/ruankaodaren\"><br>t0时刻：进程调度程序选任务T1投入运行，运行至t1时刻，共运行15ms。此时，任务T1进行I/O，共18ms (在t1~t3时间段）。<br>t1时刻：由于CPU空闲，进程调度程序选T2投入运行,运行至t2时刻，共运行15ms。此时，T2进行I/O。注意，t1~t2时间段（共15ms) T1I/O，T2运行。<br>t2时刻：由于CPU空闲，进程调度程序选T3投入运行，运行3ms后T1I/O结束。注意，t2~t3时间段（共3ms) T1、T2I/O，T3运行。<br>t3时刻：由于系统采用可剥夺式优先级的进程调度方案，所以，操作系统强行地将T3占用的CPU剥夺，分配给T1。到t4时刻任务T1运行8ms任务结束。注意，t3~t4时间段（共8ms) T1运行，T2等待，T3I/O。<br>t4时刻：将CPU分配给T3运行7ms到t5时刻，由于T2 I/O结束，操作系统强行地将T3占用的CPU剥夺，分配给T2。注意，t4~t5时间段（共7ms) T1结束，T2I/O，T3在运行。<br>t5时刻：T2开始运行，到t6时刻运行完毕共运行8ms。<br>t6时刻：系统将CPU分配给T3，运行5ms到t7时刻，T3进行I/O。<br>t7时刻：T3运行到t6时刻，进行I/O。<br>t8时刻：T3I/O结束，运行8ms到t9时刻任务T3运行结束。<br>从上分析可见，这三个任务从同时启动到全部结束的总时间为87ms，CPU的空闲时间共有18ms。","multi":0,"questionType":1,"answer":"C","chooseItem":["796235143764267009"],"itemList":[{"id":"796235143705546753","questionId":"796235142761828353","content":" 41","answer":0,"chooseValue":"A"},{"id":"796235143739101185","questionId":"796235142761828353","content":" 71","answer":0,"chooseValue":"B"},{"id":"796235143764267009","questionId":"796235142761828353","content":" 87","answer":1,"chooseValue":"C"},{"id":"796235143789432833","questionId":"796235142761828353","content":" 123","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234422373339137","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>在进程资源有向图中，圆圈表示进程，方框表示资源，方框内的小圆数表示资源数。当有向边（或称请求边）由进程指向资源时，表示申请一个资源；当有向边（或称分配边）由资源指向进程时，表示获得一个资源。假设系统中存三个进程P1、P2和P3,两种资源R1、 R2,且R1的资源数等于3, R2的资源数等于3。如果进程资源图如图(a)和图b)所示， 那么图（a）中(46):图（b）中(47)。<br> <img width=\"468\" height=\"157\" src=\"https://image.chaiding.com/ruankao/590f8321091707a62b849d727c4dcab0.jpg?x-oss-process=style/ruankaodaren\" alt=\"\">","analyze":"根据题中所述“R2的资源数等于3”，从图（a）可见已经给进程P1、P2、P3各分配1个R2资源，因此R2的可用资源数等于0。进程P1、P2、P3又分别再申请1个R2,该申请得不到满足，故进程P1、P2、P3都是阻塞节点。可见进程资源图（a）不可以化简，是死锁的。<br> 图(b)中P3只有分配边无请求边，故是非阻塞节点。P1是阻塞节点，因为它请求再获得一个R2资源，而R2的可用资源数等于0,其申请得不到满足，所以P1阻塞。P2是阻塞节点，分析同P1。又因为P3是非阻塞节点，可以运行完毕，释放其占有的1个R1资源和1个R2资源，然后P1申请1个R2资源可以得到满足，这样可以使得P1变为非阻塞节点，得到所需资源运行完毕，释放其占有资源，使得P2变为非阻塞节点，运行完毕。故进程资源图（b）可以化简，是非死锁的。","multi":0,"questionType":1,"answer":"C","chooseItem":["796234423543549953"],"itemList":[{"id":"796234423484829697","questionId":"796234422373339137","content":" P1、P2、P3都是非阻塞节点，该图可以化简，是非死锁的","answer":0,"chooseValue":"A"},{"id":"796234423514189825","questionId":"796234422373339137","content":" P1、P2、P3都是阻塞节点，该图不可以化简，是死锁的","answer":0,"chooseValue":"B"},{"id":"796234423543549953","questionId":"796234422373339137","content":" P3是非阻塞节点，P1、P2是阻塞节点，该图可以化简，是非死锁的","answer":1,"chooseValue":"C"},{"id":"796234423572910081","questionId":"796234422373339137","content":" Pl、P2是非阻塞节点，P3是阻塞节点，该图不可以化简，是死锁的","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796233942997946369","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>某文件管理系统在磁盘上建立了位示图（bitmap），记录磁盘的使用情况。若磁盘上物理块的编号依次为：0 、1、2、……；系统中的字长为32位，字的编号依次为： 0 、1、2，字中的一位对应文件存储器上的一个物理块，取值0表示该物理块空闲，取值1表示该物理块占用，如下图所示。 <img src=\"https://image.chaiding.com/ruankao/b573416860a40988925ae47a8670d7fd.jpg?x-oss-process=style/ruankaodaren\" width=\"550\" height=\"286\" title=\"\" align=\"\" alt=\"\"> <br> 假设操作系统将256号物理块分配给某文件，那么该物理块的使用情况在位示图中编号为（47）的字中描述；系统应该将（48）。","analyze":"256整除32得8余0，所以在第8个字中描述，将该字的位号0的位置“1”。","multi":0,"questionType":1,"answer":"D","chooseItem":["796233943979413505"],"itemList":[{"id":"796233943937470465","questionId":"796233942997946369","content":" 5","answer":0,"chooseValue":"A"},{"id":"796233943950053377","questionId":"796233942997946369","content":" 6","answer":0,"chooseValue":"B"},{"id":"796233943966830593","questionId":"796233942997946369","content":" 7","answer":0,"chooseValue":"C"},{"id":"796233943979413505","questionId":"796233942997946369","content":" 8","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234903715860481","title":"在支持多线程的操作系统中，假设进程P创建了若干个线程，那么（ ）是不能被其他线程共享的。","analyze":"在同一进程中的各个线程都可以共享该进程所拥有的资源，如访问进程地址空间中的每一个虚地址；访问进程所拥有的已打开文件、定时器、信号量机构等，但是不能共享进程中某线程的桟指针。","multi":0,"questionType":1,"answer":"D","chooseItem":["796234904701521921"],"itemList":[{"id":"796234904621830145","questionId":"796234903715860481","content":" 该进程的代码段","answer":0,"chooseValue":"A"},{"id":"796234904651190273","questionId":"796234903715860481","content":" 该进程中打开的文件","answer":0,"chooseValue":"B"},{"id":"796234904676356097","questionId":"796234903715860481","content":" 该进程的全局变量","answer":0,"chooseValue":"C"},{"id":"796234904701521921","questionId":"796234903715860481","content":" 该进程中线程的栈指针","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796235379115053057","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>某文件管理系统在磁盘上建立了位示图(bitmap)，记录磁盘的使用情况。若磁盘上物理块的编号依次为：0、1、2、…；系统中的字长为32位，字的编号依次为：0、1、2、…，字中的一位对应文件存储器上的一个物理块，取值0和1分别表示空闲和占用，如下图所示。<br><img alt=\"\" width=\"335\" height=\"203\" src=\"https://image.chaiding.com/ruankao/29a3541edd3883805e5f413c3cd43123.jpg?x-oss-process=style/ruankaodaren\"><br>假设操作系统将2053号物理块分配给某文件，那么该物理块的使用情况在位示图中编号为（46）的字中描述；系统应该将（47）。","analyze":"本题考查操作系统内存管理方面的基本知识。<br>文件管理系统是在外存上建立一张位示图（bitmap），来记录文件存储器的使用情况。每一位对应文件存储器上的一个物理块，取值0和1分别表示空闲和占用。<br>由于系统中字长为32位，所以每个字可以表示32个物理块的使用情况。又因为文件存储器上的物理块依次编号为：0，1，2，…，因此2056号物理块应该在位示图的第64个字中描述。又因为第64个字中的第0位对应编号为2048的物理块，第1位对应2049号物理块，第2位对应2050号物理块，第3位对应2051号物理块，第4位对应2052号物理块，第5位对应2053号物理块，所以系统应该将该字的第5位置“1”。","multi":0,"questionType":1,"answer":"B","chooseItem":["796235380062965761"],"itemList":[{"id":"796235380050382849","questionId":"796235379115053057","content":" 该字的位号5的位置“0”","answer":0,"chooseValue":"A"},{"id":"796235380062965761","questionId":"796235379115053057","content":" 该字的位号5的位置“1”","answer":1,"chooseValue":"B"},{"id":"796235380075548673","questionId":"796235379115053057","content":" 该字的位号6的位置“0”","answer":0,"chooseValue":"C"},{"id":"796235380088131585","questionId":"796235379115053057","content":" 该字的位号6的位置“1”","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234670416089089","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>某文件管理系统在磁盘上建立了位示图（bitmap），记录磁盘的使用情况。若磁盘上物理块的编号依次为：0、1、2、...；系统中的字长为64位，字的编号依次为：0、1、2、...，字中的一位对应文件存储器上的一个物理块，取值0和1分别表示空闲和占用，如下图所示：<br> <img alt=\"\" src=\"https://image.chaiding.com/ruankao/2dfdbd10763949a2422d3c6765bae7a6.jpg?x-oss-process=style/ruankaodaren\" width=\"359\" height=\"223\"><br> 假设操作系统将256号物理块分配给某文件，那么该物理块的使用情况在位示图中编号为（48）的字中描述；系统应该将（49）。","analyze":"本题考查操作系统内存管理方面的基础知识。<br> 文件管理系统是在外存上建立一张位示图（bitmap),记录文件存储器的使用情况。每一位对应文件存储器上的一个物理块，取值0和1分别表示空闲和占用。<br> 由于系统中字长为64位，所以每个字可以表示64个物理块的使用情况。根据题意“文件存储器上的物理块依次编号为：0,1,2,…”可知，位示图的第0个字对应0,1,2,…,63号物理块；第1个字对应64,65,66,…,127号物理块；第2个字对应128,129,130,…,191号物理块；第3个字对应192,193,194,…,255号物理块；第4个字对应256,257,258,…,319号物理块。256号物理块应该在位示图的第4个字中描述。又因为第4个字中的第0位对应的256号物理块，所以系统应该将该字的第0位置“1”。","multi":0,"questionType":1,"answer":"B","chooseItem":["796234671531773953"],"itemList":[{"id":"796234671510802433","questionId":"796234670416089089","content":" 3","answer":0,"chooseValue":"A"},{"id":"796234671531773953","questionId":"796234670416089089","content":" 4","answer":1,"chooseValue":"B"},{"id":"796234671556939777","questionId":"796234670416089089","content":" 5","answer":0,"chooseValue":"C"},{"id":"796234671577911297","questionId":"796234670416089089","content":" 6","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234425837834241","title":"某文件管理系统在磁盘上建立了位示图（bitmap)，记录磁盘的使用情况。若计算机系统的字长为32位（注：每位可以表示一个物理块“使用”还是“未用”的情况)，若磁盘的容量为400GB，物理块的大小为4MB，那么位示图的大小需要（48）个字。","analyze":"本题考查操作系统文件管理方面的基础知识。<br> 根据题意，计算机系统中的字长为32位，每位可以表示一个物理块的“使用”还是“未用”，一个字可记录32个物理块的使用情况。又因为1G=1024/4=256个物理块，磁盘的容量为400GB可划分成400X256=102400个物理块，位示图的大小为3200个字 (102400/32=3200)。","multi":0,"questionType":1,"answer":"C","chooseItem":["796234426890604545"],"itemList":[{"id":"796234426827689985","questionId":"796234425837834241","content":" 256","answer":0,"chooseValue":"A"},{"id":"796234426857050113","questionId":"796234425837834241","content":" 1024","answer":0,"chooseValue":"B"},{"id":"796234426890604545","questionId":"796234425837834241","content":" 3200","answer":1,"chooseValue":"C"},{"id":"796234426915770369","questionId":"796234425837834241","content":" 4098","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796235382009122817","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>进程P1、P2、P3、P4、P5和P6的前趋图如下所示：<br><img alt=\"\" width=\"263\" height=\"76\" src=\"https://image.chaiding.com/ruankao/10c9221e276e906ac5d5f0a62d775585.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制这6个进程的同步与互斥的程序如下，那么程序中的空①和空②处应分别为（48）；空③和空④处应分别为（49）；空⑤和空⑥处应分别为（50）。<br><img alt=\"\" width=\"528\" height=\"246\" src=\"https://image.chaiding.com/ruankao/224e2b3ce4fa489b04f679b73bb4bbc8.jpg?x-oss-process=style/ruankaodaren\">","analyze":"根据前驱图，P1进程运行完需要利用V操作分别通知P2、P3进程，所以空①应填V（S2），P2进程需要等待P1进程的通知，故需要利用P（S1）操作测试P1进程是否运行完，由于P3进程执行前已经用P（S2），所以空②应填P（S1）。<br>根据前驱图，P3进程需要等待P1和P2进程的通知，需要执行2个P操作，而P3进程的程序中执行前只有1个P操作，故空④应为1个P操作。P3进程运行结束需要利用1个V操作通知P5进程，故空③应为1个V操作。<br>根据前驱图，P4进程执行完需要通知P5进程，故P4进程应该执行V（S6），即空⑤应填V（S6）。P5进程运行前需要等待P3和P4进程的通知，需要执行2个P操作，故空⑥应填写P（S5）和P（S6）。<br>根据上述分析，用PV操作控制这6个进程的同步与互斥的程序如下：<br><img alt=\"\" width=\"530\" height=\"245\" src=\"https://image.chaiding.com/ruankao/8bee84a83d2fe628e08b7202c537282c.jpg?x-oss-process=style/ruankaodaren\">","multi":0,"questionType":1,"answer":"D","chooseItem":["796235382948646913"],"itemList":[{"id":"796235382906703873","questionId":"796235382009122817","content":" V(S1)和P(S2)","answer":0,"chooseValue":"A"},{"id":"796235382919286785","questionId":"796235382009122817","content":" P(S1)和V(S2)","answer":0,"chooseValue":"B"},{"id":"796235382931869697","questionId":"796235382009122817","content":" V(S1)和V(S2)","answer":0,"chooseValue":"C"},{"id":"796235382948646913","questionId":"796235382009122817","content":" V(S2)和P(S1)","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796233945950736385","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>某文件管理系统在磁盘上建立了位示图（bitmap），记录磁盘的使用情况。若磁盘上物理块的编号依次为：0 、1、2、……；系统中的字长为32位，字的编号依次为： 0 、1、2，字中的一位对应文件存储器上的一个物理块，取值0表示该物理块空闲，取值1表示该物理块占用，如下图所示。 <img src=\"https://image.chaiding.com/ruankao/ef8db21fe5bf7bb081e1734c1542762b.jpg?x-oss-process=style/ruankaodaren\" width=\"550\" height=\"286\" title=\"\" align=\"\" alt=\"\"> <br> 假设操作系统将256号物理块分配给某文件，那么该物理块的使用情况在位示图中编号为（47）的字中描述；系统应该将（48）。","analyze":"256整除32得8余0，所以在第8个字中描述，将该字的位号0的位置“1”。","multi":0,"questionType":1,"answer":"B","chooseItem":["796233946948980737"],"itemList":[{"id":"796233946902843393","questionId":"796233945950736385","content":" 该字的位号32的位置“1”","answer":0,"chooseValue":"A"},{"id":"796233946948980737","questionId":"796233945950736385","content":" 该字的位号0的位置“1”","answer":1,"chooseValue":"B"},{"id":"796233946990923777","questionId":"796233945950736385","content":" 该字的位号32的位置“0”","answer":0,"chooseValue":"C"},{"id":"796233947016089601","questionId":"796233945950736385","content":" 该字的位号0的位置“0”","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234906731565057","title":"前趋图是一个有向无环图，记为：→={(Pi，Pj)|Pi完成时间先于Pj开始时间}。假设系统中进程P={P1，P2， P3， P4， P5，P6， P7，P8}，且进程的前趋图如下：<br><img alt=\"\" width=\"183\" height=\"105\" src=\"https://image.chaiding.com/ruankao/1e71ca1d8261b094285812037c079a60.jpg?x-oss-process=style/ruankaodaren\"><br>那么，该前驱图可记为（ ）。","analyze":"本题考査操作系统基本概念。<br>前趋图(Precedence Graph)是一个有向无循环图，记为DAG(Directed Acyclic Graph),用于描述进程之间执行的前后关系。图中的每个结点可用于描述一个稈序段或进程，乃至一条语句；结点间的有向边则用于表示两个节点之间存在的偏序（Partial Order,亦称偏序关系）或前趋关系（Precedence Relation) “→”。<br>对于题中所示的前趋图，存在着前趋关系：<img alt=\"\" src=\"https://image.chaiding.com/ruankao/f9ca2cb6c51dc9048e70f966ec173a70.jpg?x-oss-process=style/ruankaodaren\" height=\"28\" width=\"318\"><br><img alt=\"\" src=\"https://image.chaiding.com/ruankao/da50d471a35803cc7df22ef387b84309.jpg?x-oss-process=style/ruankaodaren\" height=\"99\" width=\"615\"><br>注意：在前趋图中，没有前趋的结点称为初始节点（Initial Node),没有后继的节点称为终止节点（Final Node)。","multi":0,"questionType":1,"answer":"B","chooseItem":["796234907662700545"],"itemList":[{"id":"796234907637534721","questionId":"796234906731565057","content":" →={(P<sub>1</sub>，P<sub>2</sub>)， (P<sub>1</sub>，P<sub>3</sub>)， (P<sub>1</sub>，P<sub>4</sub>)， (P<sub>2</sub>，P<sub>5</sub>)，（P<sub>3</sub>，P<sub>2</sub>），（P<sub>3</sub>，P<sub>4</sub>），（P<sub>3</sub>，P<sub>6</sub>），（P<sub>4</sub>，P<sub>7</sub>），（P<sub>5</sub>，P<sub>8</sub>），（P<sub>5</sub>，P<sub>6</sub>），（P<sub>7</sub>，P<sub>8</sub>）}","answer":0,"chooseValue":"A"},{"id":"796234907662700545","questionId":"796234906731565057","content":" →={(P<sub>1</sub>，P<sub>2</sub>)， (P<sub>1</sub>，P<sub>3</sub>)， (P<sub>1</sub>，P<sub>4</sub>)， (P<sub>2</sub>，P<sub>5</sub>)，（P<sub>3</sub>，P<sub>2</sub>），（P<sub>3</sub>，P<sub>4</sub>），（P<sub>3</sub>，P<sub>6</sub>），（P<sub>4</sub>，P<sub>7</sub>），（P<sub>5</sub>，P<sub>8</sub>），（P<sub>6</sub>，P<sub>8</sub>），（P<sub>7</sub>，P<sub>8</sub>）}","answer":1,"chooseValue":"B"},{"id":"796234907687866369","questionId":"796234906731565057","content":" →={(P<sub>1</sub>，P<sub>2</sub>)， (P<sub>1</sub>，P<sub>3</sub>)， (P<sub>1</sub>，P<sub>4</sub>)， (P<sub>2</sub>，P<sub>5</sub>)，（P<sub>3</sub>，P<sub>2</sub>），（P<sub>3</sub>，P<sub>4</sub>），（P<sub>3</sub>，P<sub>5</sub>），（P<sub>4</sub>，P<sub>6</sub>），（P<sub>4</sub>，P<sub>7</sub>），（P6，P<sub>8</sub>），（P<sub>7</sub>，P<sub>8</sub>）}","answer":0,"chooseValue":"C"},{"id":"796234907713032193","questionId":"796234906731565057","content":" →={(P<sub>1</sub>，P<sub>2</sub>)， (P<sub>1</sub>，P<sub>3</sub>)， (P<sub>2</sub>，P<sub>4</sub>)， (P<sub>2</sub>，P<sub>5</sub>)，（P<sub>3</sub>，P<sub>2</sub>），（P<sub>3</sub>，P4），（P<sub>3</sub>，P<sub>5</sub>），（P<sub>4</sub>，P<sub>6</sub>），（P<sub>4</sub>，P<sub>7</sub>），（P<sub>6</sub>，P<sub>8</sub>），（P<sub>7</sub>，P<sub>8</sub>）}","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796235145760755713","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>在一个单CPU的计算机系统中，采用可剥夺式(也称抢占式)优先级的进程调度方案，且所有任务可以并行使用I/O设备。下表列出了三个任务T1、T2 、T3 的优先级、独立运行时占用CPU和I/O设备的时间。如果操作系统的开销忽略不计，这三个任务从同时启动到全部结束的总时间为（47）ms ，CPU的空闲时间共有（48）ms 。<br><img alt=\"\" width=\"458\" height=\"97\" src=\"https://image.chaiding.com/ruankao/2b3001fbf4aaebd65adc3d744bf9db1a.jpg?x-oss-process=style/ruankaodaren\">","analyze":"本题考查的是操作系统进程调度方面的知识。<br>根据题意可知，三个任务的优先级T1>T2>T3,进程调度的过程如下图所示。分析如下：<br><img alt=\"\" width=\"556\" height=\"147\" src=\"https://image.chaiding.com/ruankao/a16f52742134f5e9a2d748d4a2d7fab2.jpg?x-oss-process=style/ruankaodaren\"><br>t0时刻：进程调度程序选任务T1投入运行，运行至t1时刻，共运行15ms。此时，任务T1进行I/O，共18ms (在t1~t3时间段）。<br>t1时刻：由于CPU空闲，进程调度程序选T2投入运行,运行至t2时刻，共运行15ms。此时，T2进行I/O。注意，t1~t2时间段（共15ms) T1I/O，T2运行。<br>t2时刻：由于CPU空闲，进程调度程序选T3投入运行，运行3ms后T1I/O结束。注意，t2~t3时间段（共3ms) T1、T2I/O，T3运行。<br>t3时刻：由于系统采用可剥夺式优先级的进程调度方案，所以，操作系统强行地将T3占用的CPU剥夺，分配给T1。到t4时刻任务T1运行8ms任务结束。注意，t3~t4时间段（共8ms) T1运行，T2等待，T3I/O。<br>t4时刻：将CPU分配给T3运行7ms到t5时刻，由于T2 I/O结束，操作系统强行地将T3占用的CPU剥夺，分配给T2。注意，t4~t5时间段（共7ms) T1结束，T2I/O，T3在运行。<br>t5时刻：T2开始运行，到t6时刻运行完毕共运行8ms。<br>t6时刻：系统将CPU分配给T3，运行5ms到t7时刻，T3进行I/O。<br>t7时刻：T3运行到t6时刻，进行I/O。<br>t8时刻：T3I/O结束，运行8ms到t9时刻任务T3运行结束。<br>从上分析可见，这三个任务从同时启动到全部结束的总时间为87ms，CPU的空闲时间共有18ms。","multi":0,"questionType":1,"answer":"B","chooseItem":["796235146750611457"],"itemList":[{"id":"796235146717057025","questionId":"796235145760755713","content":" 15","answer":0,"chooseValue":"A"},{"id":"796235146750611457","questionId":"796235145760755713","content":" 18","answer":1,"chooseValue":"B"},{"id":"796235146788360193","questionId":"796235145760755713","content":" 24","answer":0,"chooseValue":"C"},{"id":"796235146821914625","questionId":"796235145760755713","content":" 54","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234909646606337","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>假设磁盘块与缓冲区大小相同，每个盘块读入缓冲区的时间为16μs，由缓冲区送至用户区的时间是5μs，在用户区内系统对每块数据的处理时间为1μs。若用户需要将大小为10个磁盘块的Doc1文件逐块从磁盘读入缓冲区，并送至用户区进行处理，那么采用单缓冲区需要花费的时间为（49）μs；采用双缓冲区需要花费的时间为（50）μs。","analyze":"在块设备输入时，假定从磁盘把一块数据输入到缓冲区的时间为T，缓冲区中的数<br>据传送到用户工作区的时间为M,而系统处理(计算)的时间为C,如下图（a）所示。<br><img alt=\"\" width=\"450\" height=\"127\" src=\"https://image.chaiding.com/ruankao/40c66a524ec7eb94674bcd92c64af562.jpg?x-oss-process=style/ruankaodaren\"><br>当第一块数据送入用户工作区后，缓冲区是空闲的，可以传送第二块数据。这样第一块数据的处理C<sub>1</sub>与第二块数据的输入T<sub>2</sub>是可以并行的，依次类推，如下图（b）所示。<br><img alt=\"\" width=\"397\" height=\"109\" src=\"https://image.chaiding.com/ruankao/81f7d70ec2897dbb5e15289f180be69e.jpg?x-oss-process=style/ruankaodaren\"><br>系统对每一块数据的处理时间为：Max(C,T)+M。因为，当T>C时，处理时间为M+T；，当T<C时，处理时间为M+C。本题每一块数据的处理时间为16+5=21，Doc1文件的处理时间为21×10+1。<br>双缓冲工作方式基本方法是在设备输入时，先将数据输入到缓冲区1，装满后便转向缓冲区2。此时系统可以从缓冲区1中提取数据传送到用户区，最后由系统对数据进行处理，如下图（c）所示。<br><img alt=\"\" width=\"358\" height=\"98\" src=\"https://image.chaiding.com/ruankao/4e1461c0cdc47231317fa10b84990ef8.jpg?x-oss-process=style/ruankaodaren\"><br>双缓冲可以实现对缓冲区中数据的输入T和提取M，与CPU的计算C，二者并行工作，如图（d）所示。从图中可以看出，双缓冲进一步加快了I/O的速度，提高了设备的利用率。在双缓冲时，系统处理一块数据的时间可以粗略地认为是Max(C,T)。如果C<T,可使块设备连续输入；如果C>T,则可使系统不必等待设备输入。本题每一块数据的处理时间为10,采用双缓冲需要花费的时间为16×10+5+1=166。<br><img alt=\"\" width=\"408\" height=\"99\" src=\"https://image.chaiding.com/ruankao/bdb09a6820031f5d335b14af54f96b69.jpg?x-oss-process=style/ruankaodaren\">","multi":0,"questionType":1,"answer":"D","chooseItem":["796234910678405121"],"itemList":[{"id":"796234910590324737","questionId":"796234909646606337","content":" 160","answer":0,"chooseValue":"A"},{"id":"796234910619684865","questionId":"796234909646606337","content":" 161","answer":0,"chooseValue":"B"},{"id":"796234910649044993","questionId":"796234909646606337","content":" 166","answer":0,"chooseValue":"C"},{"id":"796234910678405121","questionId":"796234909646606337","content":" 211","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234673691840513","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>某文件管理系统在磁盘上建立了位示图（bitmap），记录磁盘的使用情况。若磁盘上物理块的编号依次为：0、1、2、...；系统中的字长为64位，字的编号依次为：0、1、2、...，字中的一位对应文件存储器上的一个物理块，取值0和1分别表示空闲和占用，如下图所示：<br> <img alt=\"\" src=\"https://image.chaiding.com/ruankao/0daccadc6f51fbc3c6b0a92df1024495.jpg?x-oss-process=style/ruankaodaren\" width=\"359\" height=\"223\"><br> 假设操作系统将256号物理块分配给某文件，那么该物理块的使用情况在位示图中编号为（48）的字中描述；系统应该将（49）。","analyze":"本题考查操作系统内存管理方面的基础知识。<br> 文件管理系统是在外存上建立一张位示图（bitmap),记录文件存储器的使用情况。每一位对应文件存储器上的一个物理块，取值0和1分别表示空闲和占用。<br> 由于系统中字长为64位，所以每个字可以表示64个物理块的使用情况。根据题意“文件存储器上的物理块依次编号为：0,1,2,…”可知，位示图的第0个字对应0,1,2,…,63号物理块；第1个字对应64,65,66,…,127号物理块；第2个字对应128,129,130,…,191号物理块；第3个字对应192,193,194,…,255号物理块；第4个字对应256,257,258,…,319号物理块。256号物理块应该在位示图的第4个字中描述。又因为第4个字中的第0位对应的256号物理块，所以系统应该将该字的第0位置“1”。","multi":0,"questionType":1,"answer":"A","chooseItem":["796234674874634241"],"itemList":[{"id":"796234674874634241","questionId":"796234673691840513","content":" 该字的0号位置“1”","answer":1,"chooseValue":"A"},{"id":"796234674899800065","questionId":"796234673691840513","content":" 该字的63号位置“1”","answer":0,"chooseValue":"B"},{"id":"796234674924965889","questionId":"796234673691840513","content":" 该字的0号位置“0”","answer":0,"chooseValue":"C"},{"id":"796234674945937409","questionId":"796234673691840513","content":" 该字的63号位置“0”","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234428878704641","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>进程P1、P2、P3、P4和P5的前趋图如下所示：<br> <img width=\"252\" height=\"101\" src=\"https://image.chaiding.com/ruankao/6ee0097b6dfc30b9f7e48742e2a7f9f1.jpg?x-oss-process=style/ruankaodaren\" alt=\"\"><br> 若用pv操作控制这5个进程的同步与互斥的程序如下，那么程序中的空①和空②处应分別为（49）；空③和空④处应分别为（50）；空⑤和空⑥处应分别为（51）。<br> <img width=\"687\" height=\"333\" src=\"https://image.chaiding.com/ruankao/ed5386cad63a8c54140fd9d522b71ec1.jpg?x-oss-process=style/ruankaodaren\" alt=\"\">","analyze":"根据前驱图，P1进程运行完需要用V (S1)、V (S2)通知P2和P3进程，所以空①应填V(S2)，在P2进程执行前需等待P1的通知，因此应使用P(S1)，即空②应填P (S1)。<br> 根据上述分析，用PV操作控制这6个进程的同步与互斥的程序如下：<br> <img src=\"https://image.chaiding.com/ruankao/48d3f3e4f094b61d6bb41de0c283af2a.jpg?x-oss-process=style/ruankaodaren\" alt=\"\" width=\"580\" height=\"299\" title=\"\" align=\"\">","multi":0,"questionType":1,"answer":"D","chooseItem":["796234429855977473"],"itemList":[{"id":"796234429822423041","questionId":"796234428878704641","content":" V(S1)和P(S2)","answer":0,"chooseValue":"A"},{"id":"796234429835005953","questionId":"796234428878704641","content":" P(S1)和V(S2)","answer":0,"chooseValue":"B"},{"id":"796234429847588865","questionId":"796234428878704641","content":" V(S1)和V(S2)","answer":0,"chooseValue":"C"},{"id":"796234429855977473","questionId":"796234428878704641","content":" V(S2)和P(S1)","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796235148910678017","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>进程P1、P2、P3、P4、P5和P6 的前趋图如下所示：<br><img alt=\"\" width=\"257\" height=\"89\" src=\"https://image.chaiding.com/ruankao/f37eb6ff60e7bee522dd275a020e9f6c.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制这6个进程的同步与互斥的程序如下，那么程序中的空①和空②处应分别为（49）；空③和空④处应分别为（50）；空⑤和空⑥处应分别为（51）。<br><img alt=\"\" width=\"599\" height=\"277\" src=\"https://image.chaiding.com/ruankao/101bb876fefde292ce6f9283a592db82.jpg?x-oss-process=style/ruankaodaren\">","analyze":"根据前趋图P1进程运行完需要利用V操作分别通知P2、P3进程，所以空①应填V (S1) V (S2)。P2进程需要等待P1进程的通知，故需要利用P (S1)操作测试P1进程是否运行完，由于P3进程执行前已经用P(S2), 所以P2进程的空②应填P (S1)。","multi":0,"questionType":1,"answer":"C","chooseItem":["796235149934088193"],"itemList":[{"id":"796235149900533761","questionId":"796235148910678017","content":" V(S1)V(S2)和P(S2)","answer":0,"chooseValue":"A"},{"id":"796235149917310977","questionId":"796235148910678017","content":" P(S1)P(S2)和V(S2)","answer":0,"chooseValue":"B"},{"id":"796235149934088193","questionId":"796235148910678017","content":" V(S1)V(S2)和P(S1)","answer":1,"chooseValue":"C"},{"id":"796235149950865409","questionId":"796235148910678017","content":" P(S1)P(S2)和V(S1)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796235385368760321","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>进程P1、P2、P3、P4、P5和P6的前趋图如下所示：<br><img alt=\"\" width=\"263\" height=\"76\" src=\"https://image.chaiding.com/ruankao/15dfb2f51f471f0c9193e3bde438875d.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制这6个进程的同步与互斥的程序如下，那么程序中的空①和空②处应分别为（48）；空③和空④处应分别为（49）；空⑤和空⑥处应分别为（50）。<br><img alt=\"\" width=\"528\" height=\"246\" src=\"https://image.chaiding.com/ruankao/944479f2fb64df22590254108b932de8.jpg?x-oss-process=style/ruankaodaren\">","analyze":"根据前驱图，P1进程运行完需要利用V操作分别通知P2、P3进程，所以空①应填V（S2），P2进程需要等待P1进程的通知，故需要利用P（S1）操作测试P1进程是否运行完，由于P3进程执行前已经用P（S2），所以空②应填P（S1）。<br>根据前驱图，P3进程需要等待P1和P2进程的通知，需要执行2个P操作，而P3进程的程序中执行前只有1个P操作，故空④应为1个P操作。P3进程运行结束需要利用1个V操作通知P5进程，故空③应为1个V操作。<br>根据前驱图，P4进程执行完需要通知P5进程，故P4进程应该执行V（S6），即空⑤应填V（S6）。P5进程运行前需要等待P3和P4进程的通知，需要执行2个P操作，故空⑥应填写P（S5）和P（S6）。<br>根据上述分析，用PV操作控制这6个进程的同步与互斥的程序如下：<br><img alt=\"\" width=\"530\" height=\"245\" src=\"https://image.chaiding.com/ruankao/e1f0e24acfd48880643bb4b05bc5cccb.jpg?x-oss-process=style/ruankaodaren\">","multi":0,"questionType":1,"answer":"B","chooseItem":["796235386664800257"],"itemList":[{"id":"796235386631245825","questionId":"796235385368760321","content":" V(S3)和V(S5)","answer":0,"chooseValue":"A"},{"id":"796235386664800257","questionId":"796235385368760321","content":" P(S3)和V(S5)","answer":1,"chooseValue":"B"},{"id":"796235386694160385","questionId":"796235385368760321","content":" V(S3)和P(S5)","answer":0,"chooseValue":"C"},{"id":"796235386719326209","questionId":"796235385368760321","content":" P(S3)和P(S5)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796233948987412481","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>程P1、P2、P3、P4、P5和P6的前趋图如下所示：<br> <img src=\"https://image.chaiding.com/ruankao/1a91baf1ad12373328e404c0ed1a119c.jpg?x-oss-process=style/ruankaodaren\" width=\"350\" height=\"147\" title=\"\" align=\"\" alt=\"\"><br> 若用PV操作控制进程PI、P2、P3、P4、P5和P6并发执行的过程，则需要设置7个信号量S1、S2、S3、S4、S5、S6和S7， 且信号量S1~S7的初值都等于零。如下的进程执行图中，a和b处应分别填写（49）；c和 d处应分别填写（50），e和f处应分别填写（51）。<br> <img src=\"https://image.chaiding.com/ruankao/e5a6836e0c0b11733279701348dec61a.jpg?x-oss-process=style/ruankaodaren\" width=\"600\" height=\"172\" title=\"\" align=\"\" alt=\"\">","analyze":"本题考查操作系统的PV操作。<br> 根据前趋图的特性和选项进行解答。<br> 第一空：如下图所示，在p2的前面是1个P操作，P2的后面是2个V操作，然后根据第一空的选项，可以得到第一空的（a）填P（S1），（b）空填V（S2）V（S3）。<br> 第二空：如下图所示，在P3的后面是两个V操作，在P4的前面是两个p操作，然后根据第二空的选项。<br> 第三空：如下图所示，在P5的后面是1个V操作，P6的前面是两个P操作，但是在题干的图中已经有了P（S6） 。<br> <img src=\"https://image.chaiding.com/ruankao/63f9194447a96b4d5c990ac04698ca9a.jpg?x-oss-process=style/ruankaodaren\" width=\"350\" height=\"159\" title=\"\" align=\"\" alt=\"\">","multi":0,"questionType":1,"answer":"A","chooseItem":["796233949952102401"],"itemList":[{"id":"796233949952102401","questionId":"796233948987412481","content":" P（S1）和V（S2）V（S3）","answer":1,"chooseValue":"A"},{"id":"796233949981462529","questionId":"796233948987412481","content":" V（S1）和P（S2）V（S3）","answer":0,"chooseValue":"B"},{"id":"796233950015016961","questionId":"796233948987412481","content":" P（S1）和P（S2）V（S3）","answer":0,"chooseValue":"C"},{"id":"796233950048571393","questionId":"796233948987412481","content":" V（S1）和V（S2）V（S3）","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234676908871681","title":"<p><strong>请作答第<span style=\"color: red\">1</span>个空。</strong></p>假设计算机系统中有三类互斥资源Rl、R2和R3,可用资源数分别为9、5和3，若在T0时刻系统中有P1、P2、P3、P4和P5五个进程，这些进程对资源的最大需求量和已分配资源数如下表所示。在T0时刻系统剩余的可用资源数分别为（50）。如果进程按（51）序列执行，那么系统状态是安全的。<br> <img alt=\"\" src=\"https://image.chaiding.com/ruankao/1b89d752fb2aeec1582cb8d5d9120bb2.jpg?x-oss-process=style/ruankaodaren\" width=\"384\" height=\"197\">","analyze":"本题考查操作系统进程管理方面的基础知识。<br> 在操作系统进程管理中，安全状态是指系统能按某种进程顺序（P1,P2,…,Pn)，来为每个进程Pi分配其所需的资源，直到满足每个进程对资源的最大需求，使每个进程都可以顺利完成。如果无法找到这样的一个安全序列，则称系统处于不安全状态。根据己知条件可知，在T0时刻的剩余资源数计算如下：<br> 剩余资源数=资源总数（9,5,3)-己分配数（7,5,2)=(2,0,1)<br> 进程的执行序列己经给出，我们只需将四个选项按其顺序执行一遍，便可以判断出现死锁的三个序列。<br> <img src=\"https://image.chaiding.com/ruankao/dce857ef9f696b4dcad13409fcf0c0f9.jpg?x-oss-process=style/ruankaodaren\" alt=\"\" width=\"500\" height=\"127\" title=\"\" align=\"\"><br> 选项A:P1→P2→P4→P5→P3是不安全的序列。因为在这种情况下，进程P1先运行，P1尚需资源数为（3,0,1)，假设将资源R1分配3台给进程P1,则系统剩余的可用资源数为（0,0,1)，将导致系统所有的进程都不能做上能完成标志“True”，故选项A是不安全的序列。<br> 选项B:P4→P2→P1→P5→P3是不安全的序列。因为在这种情况下，进程P4先运行，P4尚需资源数为（2,2,1)，假设将资源R1分配2台给进程P4,则系统剩余的可用资源数为（0,0,1)，将导致系统所有的进程都不能做上能完成标志“True”，故选项B是不安全的序列。<br> 选项C:P5→P2→P4→P3→P1是安全的序列。因为所有的进程都能做上完成标志“True”，如下表所示。<br> <img src=\"https://image.chaiding.com/ruankao/67262370e0665e3775c957eec6d43bc6.jpg?x-oss-process=style/ruankaodaren\" alt=\"\" width=\"500\" height=\"126\" title=\"\" align=\"\"><br> 具体分析如下:<br> ①进程P5运行，系统剩余的可用资源数为(2,0,1),P5尚需资源数为(1,0,1),系统可进行分配，故进程P5能做上能完成标志\"True”,释放P5占有的资源数(1,1,0),系统可用资源数为(3,1,1)。<br> ②进程P2运行，系统剩余的可用资源数为(3,1,1),P2尚需资源数为(1,1,0),系统可进行分配，故进程P2能做上能完成标志\"True”,释放P2占有的资源数(2,1,0),系统可用资源数为(5,2,1)。<br> ③进程P4运行，系统剩余的可用资源数为(5,2,1),P4尚需资源数为(2,2,1),系统可进行分配，故进程P4能做上能完成标志\"True\",释放P4占有的资源数(1,1,1),系统可用资源数为(6,3,2)。<br> ④进程P3运行，系统剩余的可用资源数为(6,3,2),P3尚需资源数为(3,2,0),系统可进行分配，故进程P3能做上能完成标志“True”,释放P3占有的资源数(1,1,1),系统可用资源数为(7,4,2)。<br> ⑤进程P1运行，系统剩余的可用资源数为(7,4,3),P1尚需资源数为(4,2,0),系统可进行分配，故进程P1能做上能完成标志“True”,释放P1占有的资源数(1,1,1),系统可用资源数为（10, 5,3)。<br> 选项D:P5→P1→P4→P2→P3是不安全的序列。因为在选项D中，进程P5先运行，系统剩余的可用资源数为（2,0,1),P5尚需资源数为（1,0,1)，系统可进行分配，故进程P5能做上能完成标志“True”，释放P5占有的资源数（1,1,0)，系统可用资源数为（3,1,1)。进程P1运行，P1尚需资源数为（4,0,1)，假设将资源R1分配3台给进程P1,则系统剩余的可用资源数为（0,1,1),将导致系统中的进程Pl、P2、P3和P4都不能做上能完成标志“True”，故选项D是不安全的序列。","multi":0,"questionType":1,"answer":"D","chooseItem":["796234677928087553"],"itemList":[{"id":"796234677852590081","questionId":"796234676908871681","content":" 1、1和0","answer":0,"chooseValue":"A"},{"id":"796234677877755905","questionId":"796234676908871681","content":" 1、1和1","answer":0,"chooseValue":"B"},{"id":"796234677898727425","questionId":"796234676908871681","content":" 2、1和0","answer":0,"chooseValue":"C"},{"id":"796234677928087553","questionId":"796234676908871681","content":" 2、0和1","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234432049598465","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>进程P1、P2、P3、P4和P5的前趋图如下所示：<br> <img width=\"252\" height=\"101\" src=\"https://image.chaiding.com/ruankao/bcee44c6f12138957bfe9cbc1986f1e3.jpg?x-oss-process=style/ruankaodaren\" alt=\"\"><br> 若用pv操作控制这5个进程的同步与互斥的程序如下，那么程序中的空①和空②处应分別为（49）；空③和空④处应分别为（50）；空⑤和空⑥处应分别为（51）。<br> <img width=\"687\" height=\"333\" src=\"https://image.chaiding.com/ruankao/930e1c8677a21ee19651147923cf7f2f.jpg?x-oss-process=style/ruankaodaren\" alt=\"\">","analyze":"根据前驱图，P3进程运行前需要等待P1和P2的通知，故P3执行前需要执行2个V操作，由于之前已经用P(S2)，空③应为P(S3);又由于P3执行结束需要分别通知P4、P5进程，需要2个V操作，故空④应为V(S5)V(S6)。而P4进程的程序中执行前只有1个P操作，故空④应为1个P操作。<br> 根据上述分析，用PV操作控制这6个进程的同步与互斥的程序如下：<br> <img src=\"https://image.chaiding.com/ruankao/267e80d21cd89c37454ba57254930cac.jpg?x-oss-process=style/ruankaodaren\" alt=\"\" width=\"580\" height=\"299\" title=\"\" align=\"\">","multi":0,"questionType":1,"answer":"B","chooseItem":["796234433005899777"],"itemList":[{"id":"796234432980733953","questionId":"796234432049598465","content":" V(S4)和V(S5)P(S3)","answer":0,"chooseValue":"A"},{"id":"796234433005899777","questionId":"796234432049598465","content":" P(S3)和V(S5)V(S6)","answer":1,"chooseValue":"B"},{"id":"796234433039454209","questionId":"796234432049598465","content":" V(S3)和V(S4)V(S5)","answer":0,"chooseValue":"C"},{"id":"796234433064620033","questionId":"796234432049598465","content":" P(S4)和V(S4)P(S3)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796235151943159809","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>进程P1、P2、P3、P4、P5和P6 的前趋图如下所示：<br><img alt=\"\" width=\"257\" height=\"89\" src=\"https://image.chaiding.com/ruankao/b4e374fcbef2a0a555fc3d3798546660.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制这6个进程的同步与互斥的程序如下，那么程序中的空①和空②处应分别为（49）；空③和空④处应分别为（50）；空⑤和空⑥处应分别为（51）。<br><img alt=\"\" width=\"599\" height=\"277\" src=\"https://image.chaiding.com/ruankao/a8ed84f0360a3579689762dfa1f94c0f.jpg?x-oss-process=style/ruankaodaren\">","analyze":"根据前趋图P3进程需要等待P1和P2进程的通知，需要执行2个P操作，而P3进程的程序中执行前只有1个P操作，故空③应为1 个P操作。P3进程运行结束需要利用1个V操作通知P5进程，故空④应为1个V操作。","multi":0,"questionType":1,"answer":"B","chooseItem":["796235152853323777"],"itemList":[{"id":"796235152828157953","questionId":"796235151943159809","content":" V(S3)和V(S5)V(S6)","answer":0,"chooseValue":"A"},{"id":"796235152853323777","questionId":"796235151943159809","content":" P(S3)和V(S5)V(S6)","answer":1,"chooseValue":"B"},{"id":"796235152878489601","questionId":"796235151943159809","content":" V(S3)和P(S5)P(S6)","answer":0,"chooseValue":"C"},{"id":"796235152903655425","questionId":"796235151943159809","content":" P(S3)和P(S5)P(S6)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796235388757757953","title":"<p><strong>请作答第<span style=\"color: red\">3</span>个空。</strong></p>进程P1、P2、P3、P4、P5和P6的前趋图如下所示：<br><img alt=\"\" width=\"263\" height=\"76\" src=\"https://image.chaiding.com/ruankao/33e474c28491fd2d2f71340105b7447d.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制这6个进程的同步与互斥的程序如下，那么程序中的空①和空②处应分别为（48）；空③和空④处应分别为（49）；空⑤和空⑥处应分别为（50）。<br><img alt=\"\" width=\"528\" height=\"246\" src=\"https://image.chaiding.com/ruankao/e51064bbac74c5cfb25a369d7bde9f37.jpg?x-oss-process=style/ruankaodaren\">","analyze":"根据前驱图，P1进程运行完需要利用V操作分别通知P2、P3进程，所以空①应填V（S2），P2进程需要等待P1进程的通知，故需要利用P（S1）操作测试P1进程是否运行完，由于P3进程执行前已经用P（S2），所以空②应填P（S1）。<br>根据前驱图，P3进程需要等待P1和P2进程的通知，需要执行2个P操作，而P3进程的程序中执行前只有1个P操作，故空④应为1个P操作。P3进程运行结束需要利用1个V操作通知P5进程，故空③应为1个V操作。<br>根据前驱图，P4进程执行完需要通知P5进程，故P4进程应该执行V（S6），即空⑤应填V（S6）。P5进程运行前需要等待P3和P4进程的通知，需要执行2个P操作，故空⑥应填写P（S5）和P（S6）。<br>根据上述分析，用PV操作控制这6个进程的同步与互斥的程序如下：<br><img alt=\"\" width=\"530\" height=\"245\" src=\"https://image.chaiding.com/ruankao/9b8e965a4f9eb223365d081971abc995.jpg?x-oss-process=style/ruankaodaren\">","multi":0,"questionType":1,"answer":"C","chooseItem":["796235389852471297"],"itemList":[{"id":"796235389789556737","questionId":"796235388757757953","content":" P(S6)和P(S5)V(S6)","answer":0,"chooseValue":"A"},{"id":"796235389823111169","questionId":"796235388757757953","content":" V(S5)和V(S5)V(S6)","answer":0,"chooseValue":"B"},{"id":"796235389852471297","questionId":"796235388757757953","content":" V(S6)和P(S5)P(S6)","answer":1,"chooseValue":"C"},{"id":"796235389881831425","questionId":"796235388757757953","content":" P(S6)和P(S5)P(S6)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234912637145089","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>假设磁盘块与缓冲区大小相同，每个盘块读入缓冲区的时间为16μs，由缓冲区送至用户区的时间是5μs，在用户区内系统对每块数据的处理时间为1μs。若用户需要将大小为10个磁盘块的Doc1文件逐块从磁盘读入缓冲区，并送至用户区进行处理，那么采用单缓冲区需要花费的时间为（49）μs；采用双缓冲区需要花费的时间为（50）μs。","analyze":"在块设备输入时，假定从磁盘把一块数据输入到缓冲区的时间为T，缓冲区中的数<br>据传送到用户工作区的时间为M,而系统处理(计算)的时间为C,如下图（a）所示。<br><img width=\"450\" height=\"127\" alt=\"\" src=\"https://image.chaiding.com/ruankao/9795ae83347963c6cd578f7a6879ed60.jpg?x-oss-process=style/ruankaodaren\"><br>当第一块数据送入用户工作区后，缓冲区是空闲的，可以传送第二块数据。这样第一块数据的处理C<sub>1</sub>与第二块数据的输入T<sub>2</sub>是可以并行的，依次类推，如下图（b）所示。<br><img width=\"397\" height=\"109\" alt=\"\" src=\"https://image.chaiding.com/ruankao/67c54a4f46bf9d7f9b82f064d5eecf57.jpg?x-oss-process=style/ruankaodaren\"><br>系统对每一块数据的处理时间为：Max(C,T)+M。因为，当T>C时，处理时间为M+T；，当T<C时，处理时间为M+C。本题每一块数据的处理时间为16+5=21，Doc1文件的处理时间为21×10+1。<br>双缓冲工作方式基本方法是在设备输入时，先将数据输入到缓冲区1，装满后便转向缓冲区2。此时系统可以从缓冲区1中提取数据传送到用户区，最后由系统对数据进行处理，如下图（c）所示。<br><img width=\"358\" height=\"98\" alt=\"\" src=\"https://image.chaiding.com/ruankao/973d0f90b4f50e3b12c2af99c6a5660c.jpg?x-oss-process=style/ruankaodaren\"><br>双缓冲可以实现对缓冲区中数据的输入T和提取M，与CPU的计算C，二者并行工作，如图（d）所示。从图中可以看出，双缓冲进一步加快了I/O的速度，提高了设备的利用率。在双缓冲时，系统处理一块数据的时间可以粗略地认为是Max(C,T)。如果C<T,可使块设备连续输入；如果C>T,则可使系统不必等待设备输入。本题每一块数据的处理时间为10,采用双缓冲需要花费的时间为16×10+5+1=166。<br><img width=\"408\" height=\"99\" alt=\"\" src=\"https://image.chaiding.com/ruankao/903780322c6da4b13ed75e58905c1a68.jpg?x-oss-process=style/ruankaodaren\">","multi":0,"questionType":1,"answer":"C","chooseItem":["796234913631195137"],"itemList":[{"id":"796234913593446401","questionId":"796234912637145089","content":" 160","answer":0,"chooseValue":"A"},{"id":"796234913610223617","questionId":"796234912637145089","content":" 161","answer":0,"chooseValue":"B"},{"id":"796234913631195137","questionId":"796234912637145089","content":" 166","answer":1,"chooseValue":"C"},{"id":"796234913647972353","questionId":"796234912637145089","content":" 211","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796233952107974657","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>程P1、P2、P3、P4、P5和P6的前趋图如下所示：<br> <img src=\"https://image.chaiding.com/ruankao/03f8eaab06d74871fa94c9aa310583e5.jpg?x-oss-process=style/ruankaodaren\" width=\"350\" height=\"147\" title=\"\" align=\"\" alt=\"\"><br> 若用PV操作控制进程PI、P2、P3、P4、P5和P6并发执行的过程，则需要设置7个信号量S1、S2、S3、S4、S5、S6和S7， 且信号量S1~S7的初值都等于零。如下的进程执行图中，a和b处应分别填写（49）；c和 d处应分别填写（50），e和f处应分别填写（51）。<br> <img src=\"https://image.chaiding.com/ruankao/f147e671acf7a92d9f7c0bda5b4a2852.jpg?x-oss-process=style/ruankaodaren\" width=\"600\" height=\"172\" title=\"\" align=\"\" alt=\"\">","analyze":"本题考查操作系统的PV操作。<br> 根据前趋图的特性和选项进行解答。<br> 第一空：如下图所示，在p2的前面是1个P操作，P2的后面是2个V操作，然后根据第一空的选项，可以得到第一空的（a）填P（S1），（b）空填V（S2）V（S3）。<br> 第二空：如下图所示，在P3的后面是两个V操作，在P4的前面是两个p操作，然后根据第二空的选项。<br> 第三空：如下图所示，在P5的后面是1个V操作，P6的前面是两个P操作，但是在题干的图中已经有了P（S6） 。<br> <img src=\"https://image.chaiding.com/ruankao/d4a8d027d53c8413f9964fb1f3765a03.jpg?x-oss-process=style/ruankaodaren\" width=\"350\" height=\"159\" title=\"\" align=\"\" alt=\"\">","multi":0,"questionType":1,"answer":"D","chooseItem":["796233953164939265"],"itemList":[{"id":"796233953106219009","questionId":"796233952107974657","content":" V（S4）和P（S3）P（S4）","answer":0,"chooseValue":"A"},{"id":"796233953127190529","questionId":"796233952107974657","content":" P（S4）和P（S3）P（S4）","answer":0,"chooseValue":"B"},{"id":"796233953143967745","questionId":"796233952107974657","content":" P（S3）和V（S4）V（S5）","answer":0,"chooseValue":"C"},{"id":"796233953164939265","questionId":"796233952107974657","content":" V（S4）V（S5）和P（S3）P（S4）","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234435014971393","title":"<p><strong>请作答第<span style=\"color: red\">3</span>个空。</strong></p>进程P1、P2、P3、P4和P5的前趋图如下所示：<br> <img width=\"252\" height=\"101\" src=\"https://image.chaiding.com/ruankao/93169e71117d507cfbba3bf434b5a4fc.jpg?x-oss-process=style/ruankaodaren\" alt=\"\"><br> 若用pv操作控制这5个进程的同步与互斥的程序如下，那么程序中的空①和空②处应分別为（49）；空③和空④处应分别为（50）；空⑤和空⑥处应分别为（51）。<br> <img width=\"687\" height=\"333\" src=\"https://image.chaiding.com/ruankao/640efbfe5914deb31991409b3cb9ce8f.jpg?x-oss-process=style/ruankaodaren\" alt=\"\">","analyze":"根据前驱图，P4进程运行前需要等待P2和P3的通知，由于P4执行前已经用P(S4)，空⑤应为P(S5)； P5进程运行前需要等待P3和P4的通知，由于P5执行前已经用P (S6)，空⑥应填P (S7)。<br> 根据上述分析，用PV操作控制这6个进程的同步与互斥的程序如下：<br> <img src=\"https://image.chaiding.com/ruankao/fc52f9ac4fc7f83a95745f1f966e775d.jpg?x-oss-process=style/ruankaodaren\" alt=\"\" width=\"580\" height=\"299\" title=\"\" align=\"\">","multi":0,"questionType":1,"answer":"A","chooseItem":["796234437212786689"],"itemList":[{"id":"796234437212786689","questionId":"796234435014971393","content":" P(S5)和P(S7)","answer":1,"chooseValue":"A"},{"id":"796234437246341121","questionId":"796234435014971393","content":" P(S6)和P(S7)","answer":0,"chooseValue":"B"},{"id":"796234437279895553","questionId":"796234435014971393","content":" V(S5)和V(S6)","answer":0,"chooseValue":"C"},{"id":"796234437317644289","questionId":"796234435014971393","content":" V(S6)和P(S7)","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796233955257896961","title":"<p><strong>请作答第<span style=\"color: red\">3</span>个空。</strong></p>程P1、P2、P3、P4、P5和P6的前趋图如下所示：<br> <img src=\"https://image.chaiding.com/ruankao/57ad4ccc2bd7c5f356be90ba845ce343.jpg?x-oss-process=style/ruankaodaren\" width=\"350\" height=\"147\" title=\"\" align=\"\" alt=\"\"><br> 若用PV操作控制进程PI、P2、P3、P4、P5和P6并发执行的过程，则需要设置7个信号量S1、S2、S3、S4、S5、S6和S7， 且信号量S1~S7的初值都等于零。如下的进程执行图中，a和b处应分别填写（49）；c和 d处应分别填写（50），e和f处应分别填写（51）。<br> <img src=\"https://image.chaiding.com/ruankao/c91d1f2431acd6b4c76bafe974a8d4b3.jpg?x-oss-process=style/ruankaodaren\" width=\"600\" height=\"172\" title=\"\" align=\"\" alt=\"\">","analyze":"本题考查操作系统的PV操作。<br> 根据前趋图的特性和选项进行解答。<br> 第一空：如下图所示，在p2的前面是1个P操作，P2的后面是2个V操作，然后根据第一空的选项，可以得到第一空的（a）填P（S1），（b）空填V（S2）V（S3）。<br> 第二空：如下图所示，在P3的后面是两个V操作，在P4的前面是两个p操作，然后根据第二空的选项。<br> 第三空：如下图所示，在P5的后面是1个V操作，P6的前面是两个P操作，但是在题干的图中已经有了P（S6） 。<br> <img src=\"https://image.chaiding.com/ruankao/5d9dbdb8d722c2ebff2dd9bdccf6657b.jpg?x-oss-process=style/ruankaodaren\" width=\"350\" height=\"159\" title=\"\" align=\"\" alt=\"\">","multi":0,"questionType":1,"answer":"C","chooseItem":["796233956461662209"],"itemList":[{"id":"796233956398747649","questionId":"796233955257896961","content":" P（S6）和V（S7）","answer":0,"chooseValue":"A"},{"id":"796233956432302081","questionId":"796233955257896961","content":" V（S6）和P（S6）","answer":0,"chooseValue":"B"},{"id":"796233956461662209","questionId":"796233955257896961","content":" V（S7）和P（S7）","answer":1,"chooseValue":"C"},{"id":"796233956486828033","questionId":"796233955257896961","content":" V（S6）和V（S7）","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234679886827521","title":"<p><strong>请作答第<span style=\"color: red\">2</span>个空。</strong></p>假设计算机系统中有三类互斥资源Rl、R2和R3,可用资源数分别为9、5和3，若在T0时刻系统中有P1、P2、P3、P4和P5五个进程，这些进程对资源的最大需求量和已分配资源数如下表所示。在T0时刻系统剩余的可用资源数分别为（50）。如果进程按（51）序列执行，那么系统状态是安全的。<br> <img alt=\"\" src=\"https://image.chaiding.com/ruankao/b4ca10ffad70396c7df95d58d6a9295c.jpg?x-oss-process=style/ruankaodaren\" width=\"384\" height=\"197\">","analyze":"本题考查操作系统进程管理方面的基础知识。<br> 在操作系统进程管理中，安全状态是指系统能按某种进程顺序（P1,P2,…,Pn)，来为每个进程Pi分配其所需的资源，直到满足每个进程对资源的最大需求，使每个进程都可以顺利完成。如果无法找到这样的一个安全序列，则称系统处于不安全状态。根据己知条件可知，在T0时刻的剩余资源数计算如下：<br> 剩余资源数=资源总数（9,5,3)-己分配数（7,5,2)=(2,0,1)<br> 进程的执行序列己经给出，我们只需将四个选项按其顺序执行一遍，便可以判断出现死锁的三个序列。<br> <img src=\"https://image.chaiding.com/ruankao/d7641947a362e7803400b53f6d357d4d.jpg?x-oss-process=style/ruankaodaren\" alt=\"\" width=\"500\" height=\"127\" title=\"\" align=\"\"><br> 选项A:P1→P2→P4→P5→P3是不安全的序列。因为在这种情况下，进程P1先运行，P1尚需资源数为（3,0,1)，假设将资源R1分配3台给进程P1,则系统剩余的可用资源数为（0,0,1)，将导致系统所有的进程都不能做上能完成标志“True”，故选项A是不安全的序列。<br> 选项B:P4→P2→P1→P5→P3是不安全的序列。因为在这种情况下，进程P4先运行，P4尚需资源数为（2,2,1)，假设将资源R1分配2台给进程P4,则系统剩余的可用资源数为（0,0,1)，将导致系统所有的进程都不能做上能完成标志“True”，故选项B是不安全的序列。<br> 选项C:P5→P2→P4→P3→P1是安全的序列。因为所有的进程都能做上完成标志“True”，如下表所示。<br> <img src=\"https://image.chaiding.com/ruankao/6ff972618607db38b0ad430858119098.jpg?x-oss-process=style/ruankaodaren\" alt=\"\" width=\"500\" height=\"126\" title=\"\" align=\"\"><br> 具体分析如下:<br> ①进程P5运行，系统剩余的可用资源数为(2,0,1),P5尚需资源数为(1,0,1),系统可进行分配，故进程P5能做上能完成标志\"True”,释放P5占有的资源数(1,1,0),系统可用资源数为(3,1,1)。<br> ②进程P2运行，系统剩余的可用资源数为(3,1,1),P2尚需资源数为(1,1,0),系统可进行分配，故进程P2能做上能完成标志\"True”,释放P2占有的资源数(2,1,0),系统可用资源数为(5,2,1)。<br> ③进程P4运行，系统剩余的可用资源数为(5,2,1),P4尚需资源数为(2,2,1),系统可进行分配，故进程P4能做上能完成标志\"True\",释放P4占有的资源数(1,1,1),系统可用资源数为(6,3,2)。<br> ④进程P3运行，系统剩余的可用资源数为(6,3,2),P3尚需资源数为(3,2,0),系统可进行分配，故进程P3能做上能完成标志“True”,释放P3占有的资源数(1,1,1),系统可用资源数为(7,4,2)。<br> ⑤进程P1运行，系统剩余的可用资源数为(7,4,3),P1尚需资源数为(4,2,0),系统可进行分配，故进程P1能做上能完成标志“True”,释放P1占有的资源数(1,1,1),系统可用资源数为（10, 5,3)。<br> 选项D:P5→P1→P4→P2→P3是不安全的序列。因为在选项D中，进程P5先运行，系统剩余的可用资源数为（2,0,1),P5尚需资源数为（1,0,1)，系统可进行分配，故进程P5能做上能完成标志“True”，释放P5占有的资源数（1,1,0)，系统可用资源数为（3,1,1)。进程P1运行，P1尚需资源数为（4,0,1)，假设将资源R1分配3台给进程P1,则系统剩余的可用资源数为（0,1,1),将导致系统中的进程Pl、P2、P3和P4都不能做上能完成标志“True”，故选项D是不安全的序列。","multi":0,"questionType":1,"answer":"C","chooseItem":["796234680889266177"],"itemList":[{"id":"796234680826351617","questionId":"796234679886827521","content":" P1→P2→P4→P5→P3","answer":0,"chooseValue":"A"},{"id":"796234680859906049","questionId":"796234679886827521","content":" P4→P2→P1→P5→P3","answer":0,"chooseValue":"B"},{"id":"796234680889266177","questionId":"796234679886827521","content":" P5→P2→P4→P3→P1","answer":1,"chooseValue":"C"},{"id":"796234680918626305","questionId":"796234679886827521","content":" P5→Pl→P4→P2→P3","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796235154866589697","title":"<p><strong>请作答第<span style=\"color: red\">3</span>个空。</strong></p>进程P1、P2、P3、P4、P5和P6 的前趋图如下所示：<br><img alt=\"\" width=\"257\" height=\"89\" src=\"https://image.chaiding.com/ruankao/e9dab16c13f7166855d065d91bfe00a3.jpg?x-oss-process=style/ruankaodaren\"><br>若用PV操作控制这6个进程的同步与互斥的程序如下，那么程序中的空①和空②处应分别为（49）；空③和空④处应分别为（50）；空⑤和空⑥处应分别为（51）。<br><img alt=\"\" width=\"599\" height=\"277\" src=\"https://image.chaiding.com/ruankao/b328296ab8549706a2842d74877753f8.jpg?x-oss-process=style/ruankaodaren\">","analyze":"根据前趋图P4进程执行完需要通知P6进程，故P4进程应该执行V(S7)，即空⑤应填V(S7)。P6进程运行前需要等待P4和P5进程的通知，需要执行2个P操作，故空⑥应填写P(S7)和P (S8)。<br>根据上述分析，用PV操作控制这6个进程的同步与互斥的程序如下：<br><img width=\"599\" height=\"275\" alt=\"\" src=\"https://image.chaiding.com/ruankao/94a115ab2850735e83b735809f20186e.jpg?x-oss-process=style/ruankaodaren\">","multi":0,"questionType":1,"answer":"D","chooseItem":["796235155843862529"],"itemList":[{"id":"796235155789336577","questionId":"796235154866589697","content":" P(S6)和P(S7)V(S8)","answer":0,"chooseValue":"A"},{"id":"796235155806113793","questionId":"796235154866589697","content":" V(S6)和V(S7)V(S8)","answer":0,"chooseValue":"B"},{"id":"796235155818696705","questionId":"796235154866589697","content":" P(S6)和P(S7)P(S8)","answer":0,"chooseValue":"C"},{"id":"796235155843862529","questionId":"796235154866589697","content":" V(S7)和P(S7)P(S8)","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796235391995760641","title":"I/O设备管理一般分为4个层次，如下图所示。图中①②③分别对应（51）。<br><img alt=\"\" width=\"299\" height=\"133\" src=\"https://image.chaiding.com/ruankao/fd0a77da3801573191810e67b4223be3.jpg?x-oss-process=style/ruankaodaren\">","analyze":"I/O设备管理软件一般分为4层：中断处理程序、设备驱动程序、与设备无关的系统软件和用户级软件。至于一些具体分层时细节上的处理，是依赖于系统的，没有严格的划分，只要有利于设备独立这一目标，可以为了提高效率而设计不同的层次结构。I/O软件的所有层次及每一层的主要功能如下图所示。<br><img alt=\"\" width=\"301\" height=\"139\" src=\"https://image.chaiding.com/ruankao/588245b7582173d8bb8e9311a13f9adf.jpg?x-oss-process=style/ruankaodaren\"><br>图中的箭头给出了I/O部分的控制流。<br>这里举一个读硬盘文件的例子。当用户程序试图读一个硬盘文件时，需要通过操作系统实现该操作。与设备无关软件检查高速缓存中有无要读的数据块。若没有，则调用设备驱动程序，向I/O硬件发出一个请求。然后，用户进程阻塞并等待磁盘操作的完成。当磁盘操作完成时，硬件产生一个中断，转入中断处理程序中断处理程序检查中断的原因，认识到这时磁盘读取操作已经完成，于是唤醒用户进程取回从磁盘读取的信息，从而结束此次I/O请求。用户进程在得到了所需的硬盘文件内容之后，继续运行。","multi":0,"questionType":1,"answer":"D","chooseItem":["796235393119834113"],"itemList":[{"id":"796235393019170817","questionId":"796235391995760641","content":" 设备驱动程序、虚设备管理、与设备无关的系统软件","answer":0,"chooseValue":"A"},{"id":"796235393052725249","questionId":"796235391995760641","content":" 设备驱动程序、与设备无关的系统软件、虚设备管理","answer":0,"chooseValue":"B"},{"id":"796235393082085377","questionId":"796235391995760641","content":" 中断处理程序、与设备无关的系统软件、设备驱动程序","answer":0,"chooseValue":"C"},{"id":"796235393119834113","questionId":"796235391995760641","content":" 中断处理程序、设备驱动程序、与设备无关的系统软件","answer":1,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234915610906625","title":"某系统磁盘数据块的大小为1024KB，系统磁盘管理采用索引文件结构，每个索引指针占用4个字节。一个索引文件的索引节点有8个直接块地址、1个一级间接块地址、1个二级间接块地址和1个三级间接块地址。假设索引节点已经在内存中，那么访问该文件偏移地址9089k字节的数据需要再访问（ ）次磁盘。","analyze":"由于一个磁盘数据块的大小为:1024KB，索引文件一共有8个直接块地址，所以直接索引范围达到8192KB。文件偏移地址为9089字节，这个位置属于直接索引，故需要访问1次磁盘。","multi":0,"questionType":1,"answer":"A","chooseItem":["796234916575596545"],"itemList":[{"id":"796234916575596545","questionId":"796234915610906625","content":" 1","answer":1,"chooseValue":"A"},{"id":"796234916604956673","questionId":"796234915610906625","content":" 2","answer":0,"chooseValue":"B"},{"id":"796234916630122497","questionId":"796234915610906625","content":" 3","answer":0,"chooseValue":"C"},{"id":"796234916646899713","questionId":"796234915610906625","content":" 4","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234682885754881","title":"“从减少成本和缩短研发周期考虑，要求嵌入式操作系统能运行在不同的微处理器平台上，能针对硬件变化进行结构与功能上的配置。”是属于嵌入式操作系统（ ）特点。","analyze":"本题考查嵌入式操作系统的基本概念。<br> \nPS:2023.05.16更新解析\n（1）微型化，从性能和成本角度考虑，希望占用的资源和系统代码量少；\n（2）可定制，从减少成本和缩短研发周期考虑，要求嵌入式操作系统能运行在不同的微处理器平台上，能针对硬件变化进行结构与功能上的配置，以满足不同应用的需求；\n（3）实时性，嵌入式操作系统主要应用于过程控制、数据采集、传输通信、多媒体信息及关键要害领域需要迅速响应的场合，所以对实时性要求较高；\n（4）可靠性，系统构件、模块和体系结构必须达到应有的可靠性，对关键要害应用还要提供容错和防故障措施；\n（5）易移植性，为了提高系统的易移植性，通常采用硬件抽象层和板级支撑包的底层设计技术。","multi":0,"questionType":1,"answer":"A","chooseItem":["796234683917553665"],"itemList":[{"id":"796234683917553665","questionId":"796234682885754881","content":" 可定制","answer":1,"chooseValue":"A"},{"id":"796234683955302401","questionId":"796234682885754881","content":" 实时性","answer":0,"chooseValue":"B"},{"id":"796234683980468225","questionId":"796234682885754881","content":" 可靠性","answer":0,"chooseValue":"C"},{"id":"796234684005634049","questionId":"796234682885754881","content":" 易移植性","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796234918681137153","title":"某系统采用请求页式存储管理方案，假设某进程有6个页面，系统给该进程分配了4个存储块，其页面变换表如下表所示，表中的状态位等于1和0分别表示页面在内存或不在内存。当该进程访问的第4号页面不在内存时，应该淘汰表中页面号为（ ）的页面。<br><img alt=\"\" src=\"https://image.chaiding.com/ruankao/117539062e37a46fb040f5c0375d0a8e.jpg?x-oss-process=style/ruankaodaren\" height=\"191\" width=\"369\">","analyze":"本题考查操作系统存储管理方面的基础知识。<br>为了实现请求分页式存储管理，必须对分页式存储管理中地址变换机构进行扩充，除了页号对应的物理块号，还增加了访问位和修改位等。当访问的页面不在内存时，需要淘汰页面的优先顺序如下表所示。<br><img width=\"571\" height=\"120\" alt=\"\" src=\"https://image.chaiding.com/ruankao/571e366373d49f37d86f80f4989d86f9.jpg?x-oss-process=style/ruankaodaren\">","multi":0,"questionType":1,"answer":"C","chooseItem":["796234919691964417"],"itemList":[{"id":"796234919645827073","questionId":"796234918681137153","content":" 1","answer":0,"chooseValue":"A"},{"id":"796234919670992897","questionId":"796234918681137153","content":" 2","answer":0,"chooseValue":"B"},{"id":"796234919691964417","questionId":"796234918681137153","content":" 3","answer":1,"chooseValue":"C"},{"id":"796234919721324545","questionId":"796234918681137153","content":" 5","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null},{"id":"796235206959845377","title":"在Linux中，可以使用（ ）命令为计算机配置IP地址。","analyze":"本题考查Linux基本配置命令的基础知识。<br>在Linux中，为计算机配置IP地址的命令格式为： <br>ifconfig interfacelD IPAddress NetMask<br>ipconfig是干扰项，在Windows操作系统下配置IP地址的命令。","multi":0,"questionType":1,"answer":"A","chooseItem":["796235208016809985"],"itemList":[{"id":"796235208016809985","questionId":"796235206959845377","content":" ifconfig","answer":1,"chooseValue":"A"},{"id":"796235208050364417","questionId":"796235206959845377","content":" config","answer":0,"chooseValue":"B"},{"id":"796235208071335937","questionId":"796235206959845377","content":" ip-address","answer":0,"chooseValue":"C"},{"id":"796235208088113153","questionId":"796235206959845377","content":" ipconfig","answer":0,"chooseValue":"D"}],"userAnswer":null,"userChooseItem":null,"answerCorrect":null,"userCollect":null}]}}
