操作系统概念练习题

单选1.-When a running process performs a blocking I/O operation before the expiration ofits time slice, it would be placed in:当正在运行的进程在其时间片到期之前执行阻塞I / O操作时，它将被放置在：a).-The ready queue as another process is scheduled;b).-The device queue for the specific I/O device; c).-The signal-waiting queue;d).-None of the above;2.-In Unix, a parent process obtains the exit status of it child process by usingthe following system call:在Unix中，父进程通过使用以下系统调用获取其子进程的退出状态：a).-exit();b).-wait();c).-fork();d).-None of the above;3.-Right after returning of a successful fork system call, parent and child memoryis marked as the following type of memory by the operating system:-成功返回fork系统调用后，操作系统会将父级和子级内存标记为以下类型的内存：a).-Virtual memory;b).-Dynamic memory;c).-COW memory;d).-All of the above;4.-Right after returning of a successful fork system call a parent and child sharethe following sections of memory:成功返回派生系统调用后，父级和子级共享以下部分内存：a).-heap;b).-stack;c).-text;d).-All of the above;5.-If you are using a multiprocessor system and want to protect a short criticalsection, the best and most efficient choice will be:如果您使用的是多处理器系统，并且希望保护较短的关键部分，则最佳和最有效的选择将是：a).-disabling interrupts;b).-A lock implemented using hardware atomic instruction;c).-Shared memory;d).-None of the above6.-In Unix, a parent process creates a child process by using the following system call: 在Unix中，父进程通过使用以下系统调用创建子进程：a).-exec();b).-wait();c).-fork();d).-None of the above;7.-The following is a software-based solution to the process synchronization problem: .-以下是基于软件的解决方案，用于解决流程同步问题：a).-Peterson’s solutionb).-TestAndSet instructionc).-Enable disable interrupts instructiond).-None of the previous8.-In Unix, a process’s PCB remains used until:8.-在Unix中，进程的PCB一直使用到：a).-The process invokes exit();b).-The parent of the process invokes wait() on the process;c).-The process invokes exit() or terminates and the parent invokes wait() onthe process.d).-None of the above.9.-If you are using a uniprocessor system and want to protect a short critical section inthe kernel code, the best and most efficient choice will be:如果您使用的是单处理器系统，并且希望保护内核代码中的一小段关键部分，则最佳和最有效的选择是：a).-disabling interrupts;b).-A lock implemented using atomic hardware instruction;c).-A semaphore implemented in the OS kernel; d).-Noneof the above10.-The principle of time-sharing ensures that:分时共享原则确保：a).-Multiple programs are loaded in memory and executed in sequence as thecurrent program blocks due to I/O;b).-The operating system loads multiple programs in memory and switches theCPU among them in a frequent manner so as to give them their impression of having a dedicated CPU;c).-All of the above;d).-None of the above;11.-An interrupt transfers control to the interrupt service routine by using:11.-中断通过使用以下命令将控制权转移到中断服务程序：a).-A system call;b).-Function pointers in an interrupt vector;c).-A regular function call;d).-None of the abovez12.-When the time slice for a running process expires, the process will be placed in:a).-The ready queue as another process is scheduled;b).-The device queue for the specific I/O device;c).-The signal-waiting queue;d).-None of the above;13.- Two processes are using an IPC communication implemented in the kernel, what isthe minimum overhead required from the moment the sender does a post to the moment the receiver process gets access to the communicated data (assume sender was running at the beginning):13.-两个进程正在使用在内核中实现的IPC通信，从发送方发帖到接收方进程访问所通信的数据（假设发送方在开始时运行）到所需的最小开销是多少？：a).-2 system calls and 2 context switches;b).-2 system calls and 1 context switch;c).-2 system calls and 3 context switches;d).-None of the above;14.-The main disadvantage of the Peterson’s solution to the critical section problem is:Peterson解决关键截面问题的主要缺点是：a).-It does not have busy waiting;b).-It cannot be extended to more than two processes;c).-It is too complex;d).-None of the above;15.-The prthread interface to wait or synchronize with child threads is:等待或与子线程同步的prthread接口是：a).-pthread_merge();b).-pthread_wait();c).-pthread_sync().d).-None of the above.16.- Define the process control block (PCB) and mention 4 items stored in it.16.-定义过程控制块（PCB）并提及其中存储的4个项目。

17.- Compare the cost of user-level threads, kernel level threads, and processcontext switches; use analogies to the costs of known events like a function call,system call, etc.17.-比较用户级线程，内核级线程和进程上下文切换的成本；用类似于已知事件的成本进行比较，例如函数调用，系统调用等。

18.- What is an up-call and what are its main disadvantages?18.-什么是电话咨询，其主要缺点是什么？19.-Mention and briefly explain three POSIX thread calls.57/500019.提及并简要解释三个POSIX线程调用。