西安电子科技大学操作系统期末试题及答案解析

西安电子科技大学

考试时间120 分钟

试题

题号一二三四五六七八九十总分分数

1.考试形式：闭卷

2.考试日期：年月日

3.本试卷共四大题，满分100分

班级学号姓名任课老师

Part 1: Select one answer (A through D) for each question ( Total 20, each 2 )

1.A computer system consists of , system programs and

application programs.

A.Control bus

B. data bus

C.Address bus

D. hardware

2.Thread（线程）can be implemented in .

A.Kernel Space

B. User Space

C. Kernel Space or User Space

D. None of the above

3.In OS, short term schedule（调度）means .

A. Job scheduling

B. Process scheduling

C. Thread scheduling

D. CPU scheduling

4.Which one of the following item is not shared by all threads in a

process? .

A. Address space

B. Register

C. Open files

D. Accounting information

5.In the paged memory management system, the address is composed

of page number and the offset within the page. In the address structure shown in the following figure, .

31 10 9 0

A. page size is 512, 2M pages at most

B. page size is 1k, 4M pages at most

C. page size is 2k, 8M pages at most

D. page size is 4k, 16M pages at most

6.Virtual memory is based on The Principle of Locality. Which of the

following statements about The Principle of Locality is correct?

A. Program executes codes in order

B.Program assesses（访问）memory in a non-uniform manner

C.Program accesses a lot of variables continuously

D.Program accesses a relatively small portion of the address space at

any instant of time

7.In UNIX i-node scheme, a directory entry contains only two fields: the

file name (14 bytes) and the number of the i-node for that file (2 bytes).

These parameters（参数）limit the number of files per file system to

.

A. 64k

B. 32k

C. 16k

D. 4k

8.The time required to read or write a disk block is determined（决定）

by three factors. Which one dominates（主导，占优势）the other two times? .

A. Seek time

B. Rotational delay time

C. Data transfer time

D. None of above

9.The chmod command（命令）is used to change the permission（许

可）of file in Linux. To use it, you specify the desired permission setting and the file or files that you wish to modify. The permission settings are usually a series of bits. Which of the following bits present that the file’s owner may read, write, and execute the file, while all others may only read the file? .

A. 755

B. 744

C. 644

D. 611

10.The method listed below doesn’t need CPU to

participate in the transfer of data block.

A.Interrupt-Driven I/O

B. DMA

C. Programmed I/O

D. None of above

Part2: Fill Blanks (Total 20, each 2)

1.Operating System is an extended machine and .