操作系统2010年操作系统本科试卷

Operating System Exam (For Grade 2000)

Class Name Student ID

一、For each of the following statements, Choosing T rue or False （24 marks）

1. Binary semaphores are those that are used by no more than two threads.

2. The Banker's algorithm is a way of preventing deadlock .

3. A multi-level indexed file permits faster random access than a contiguously allocated file.

4. An atomic operation is a machine instruction or a sequence of instructions that must be executed to completion without interruption.

5. Deadlock is a situation in which two or more processes (or threads) are waiting for an event that will occur in the future.

6. Starvation is a situation in which a process is denied access to a resource because of the competitive activity of other, possibly unrelated, processes.

7. While a process is blocked on a semaphore's queue, it is engaged in busy waiting.

8. Mutual exclusion can be enforced with a general semaphore whose initial value is greater than 1.

9. External fragmentation can be prevented (almost completely) by frequent use of compaction, but the cost would be too high for most systems.

10. A page frame is a portion of main memory.

11. The working set of a process can be changed in response to actions by other processes.

12. Thrashing will never be a problem if the system has 1 GB of real memory.

13. A printer is an example of a logical resource.

14. Versions of OS/360 are still widely used today.

15. When an executing process is stopped by the scheduler, it is said to be blocked.

16.Interrupts are used to achieve a typical timesharing OS.

二、Multiple Choice Questions (30 marks)

For each of the following questions, There is only one correct answer.

1. What is the purpose of system calls?

a) System calls allow user-level processes to gain resources from the operating system.

b) System calls are the standard interface between a user process and a kernel process.

c) System calls allow user-level processes to request services of the operating system.

d) There is no real purpose to system calls.

2. Threads belonging to the same process share the

a) stack b) data section

c) register set d) thread ID

3. In Many-to-One thread m odel, What would happen if a thread in a multithreaded process makes a blocking system call ?

a) the other threads of the process would continue to run

b) the entire process would get blocked

c) the blocking thread will get killed

d) the blocking thread will never get to run again

4. Which of the following Operating systems uses preemptive scheduling?

a) Mac OS 8 b) Windows 3.x

c) Windows 2000 d) DOS 6.0