os操作系统考试参考题

6 T/F-One kind of system interrupt ,the trap, relates to an error or exception condition in the currently running process. 7 T/F-The process

13 T/F-In a memory system employing paging, the chunks of a process(called frames) can be assigned to available chunks of memory(called pages).

14 T/F-A memory system employing segmentation consists of a number of user program segments that must be of the same length and leave a maximum segment length.

17 T/F-Double buffering refers to the concept of using two buffers to alternatively fill and empty in order to facilitate the buffering of an I/O request.

18 T/F-A pile file refers to the least complicated form of the file organization, where data are collected in sorted order and each record consists of one burst of data.

19 T/F-In the general indexed file structure, there are no key fields and variable-length records are allowed.

20 T/F- Typically, an interactive user or a process has associated with it a current directory, often referred to as the working directory. 21 T/F-In a uniprocessor machine, concurrent processes cannot be overlapped; they can only be interleaved.

22 T/F-In indirect addressing, as applied to message passing messages are sent to a temporary shared data structure typically known as a mailbox.

23 T/F-Deadlock can be defined as the periodic blocking of a set of processes that either compete for system resources or communicate with each other.

24 T/F-A reusable resource is one that can be safely used by only one process at a time and is not depleted by that use 选择题D,B,C,D,D, B,A,D,C,A, C,A,B,A,A, C,D,D 1 A primary objective of an operating sys tem is: a. Convenlence b. Efficleary c. Ability to d. All of the above

2 The operating system provides many types of services to end-users,programmers and system designers,including: a.Built-in user applications b.Error detection and response

c.Relational database capabilities with the internal file system. d.All of the above

3 The behavior of a processor can be characterized by examining: a.A single process trace b.Multiple process rtaces

c.The interleaving of the process traces

d.All of the above

4 There are a number of conditions that can be lead to process termination,including:

a. Normal completion b. Bounds violation c. Parent termination d. All of the above

5 A Memory Table is an O/S structure that is used by the O/S to: a. Manage I/O devices b. Manage processed c. Provide information about system files d. None of the above 6 The type of scheduling that involves the decision to add a process to those that are at least partially in main memory and therefore available for execution is referred to as:

a. Long-term scheduling b. Medium-term scheduling c. I/O scheduling d. None of the above

7.In terms of frequency of execution, the short-term schedulers is usually the one that executes:

a. Most frequently b.Least frequently c.About the same as the other schedulers d.None of the above 8 A problem with the largely obsolete Fixed Partitioning memory management technique is that of:

a. Allowing only a fixed number of Processes b. Inefficient use of memory

c. Internal fragmentation d. All of the above

9 An actual location in main memory is called a(n): a. Relative address b. Logical address c. Absolute address d. None of the above

10 The situation that occurs when the desired page table entry is not found in the Translation Lookaside Buffer(TLB)is called: a.TLB miss b.TLB hit

c.Page fault d.None of the above

11 In a combined paging/segmentation system, a user’s address space is broken up into a number of:

a. Segments or pages, at the discretion of the programmer.

b. Fixed-size pages, which are in turn broken down into variable-sized segments.

c. Variable-sized Segments, which are in turn broken down into fixed-sized pages. d.. All of the above.

12 An example of a block-oriented I/O device is: a. CD-ROM b. Printer c. Modem d. All of the above 13 Sequential files are optimal in scenarios involving: a. Applications that require frequent queries

b. Applications that require the processing of all records in the file c. Applications that require infrequent updates

d. All of the above

14 In a tree-structured directory, the series of directory names that culminates in a file name is referred to as the: a. Pathname b. Working directory c. Symbolic name d. None of the above

15 In order to implement mutual exclusion on a critical resource for competing processes, only one program at a time should be allowed: a. In the critical section of the program b. To perform message passing

c.To Exhibit cooperation d.None of the above 16 A resource that can be created and destroyed is called a : a. Reusable resource b. Producible resource c. Consumable resource d. All of the above

17 A condition of policy that must be present for a deadlock to be possible is:

a. Mutual exclusion b. Hold and wait c. No preemption d. All of the above

18 In deadlocked process recovery, selection criteria for choosing a particular process to abort or rollback includes designating the process with the:

a. Most estimated time remaining b. Lowest priority c. Least total resources allocated so far. d. All of the above

填空题

1. The portion of the operating system that selects the next process to run is called the dispatcher.

2. When the O/S creates a process at the explicit request of an existing process, the action is referred to as process spawning. 3. A process that cannot execute until some event occurs is said to be in the blocked state.

4. In a system that implements two suspend states, a process that has been swapped out of main memory and into secondary memory and that is also awaiting an event is in the Blocked/Suspend state.

5. The task of assianina processes to the processor or processors over time, in a way that meets system objectives is called scheduling. 6. Medium-term scheduling is part of the system swapping function. 7. Shortest process next(SPN) is a scheduling policy in which the process with the shortest expected processing time is selected next, but there is no preemption.

8. The task of subdividing memory between the O/S and processes is performed automatically by the O/S and is memory management. 9. The phenomenon in which is wanted space internal in a partition due to the fact that the block of data loaded is smaller than partition, is referred to as internal fragmentation.

10. In the Dynamic Partitioning technique of memory management, the process of shifting processes so they occupy a single contiguous block in memory is called compacting.

11. In a system that employs a paging memory management scheme, the page table shows the frame location for each page of the process.

12. The situation where the processor spends most of its time swapping process rather than executing instructions is called thrashing.

13. Most virtual memory schemes make use of a special high-speed cache for page table entries, called a (translation lookaside buffer) TLB.

14. The term data rate refers to the speed with which data moves and from the individual I/O device.

15. A hard drive is an example of a block-oriented I/O device. 16. The disk scheduling algorithm that implements exactly 2 subqueues in a measure to avoid the problem of “arm stickiness” is the FSCAN policy.

17. The file directory information element that holds information such as the permitted actions on the file(e.g., reading, writing, executing, etc. ) is the access control information element. 18. Typically, an interactive user or a process has associated with it a

current directory, often referred to as the working directory . 19. The data structure or table that is used to keep track of the portions assigned to a file is referred to as a file allocation table (FAT).

20. UNIX employs inodes, which is a control structure that contains the key information needed by the operating system for a particular file.

21. The situation where Process 1(P1) holds Resource 1(R1), while P2 holds R2, and P1 needs R2 to complete and P2 needs R1 to complete is referred to as deadlock.

22. When only one process is allowed in its critical code section at a time, then mutual exclusion is enforced.

23. A monitor supports synchronization by the use of condition variables that are contained within the monitor and accessible only within the monitor.

24. All deadlocks involve conflicting needs for resources by two or more processes.