[单项选择]An operating system is no guarantee of online security probably because ______.


A. some OS suppliers are not trustworthy
B. it still fails to shield users from intrusions
C. antivirus software is not updated in due time
D. some terminals are not installed with such a system

[单项选择]An operating system is no guarantee of online security probably because ______.
A. some OS suppliers are not trustworthy
B. it still fails to shield users from intrusions
C. antivirus software is not updated in due time
D. some terminals are not installed with such a system

[单项选择]The operating system has several major components，including the (64) ，a memory management system，the file system manager，device drivers，and the system libraries．
A. application kernel
B. information kernel
C. network kernel
D. system kernel

[单项选择]As an operating system repeatedly allocates and flees storage space，many physically separated unused areas appear.This phenomenon is called______
A. fragmentation
B. compaction
C. swapping
D. paging

[单项选择]A disk scheduling mechanism in an operating system causes the disk arm to sweepbackand forth across the disk Surface servicing all requests in its path.This is a （）
A. First Come First Serve
B. Shortest Seek Time First
C. Scan
D. None of the above

[单项选择]An operating system is (74) .
A. the highest layer of software
B. the lowest layer of software
C. the highest layer of hardware
D. the lowest layer of hardware

[单项选择]As an operating system repeatedly allocates and frees storage space, many physically separated unused areas appear. This phenomenon is called ______.
A. fragmentation
B. compaction
C. swapping
D. paging

[单项选择]Most of the host operating system provides a way for a system administrator to manually configure the IP information needed by a host．Automated configuration methods, such as （）, are required to solve the problem．
A. IPsec
B. DHCP
C. PPTP
D. SOAP

[单项选择]Assume that an operating system uses a round—robin scheduler. The process's quantum is 20 msec, and the context switch is 5 msec. What percentage of the CPU's time is spent on administrative overhead ( )
A. 5%
B. 15%
C. 20%
D. 25%

[单项选择]

The operating system provides and easy-to-use （） to users．

A. interface
B. hardware
C. device
D. disk

[单项选择]

（）is a single-user multi-task operating system．

A. MS-DOS
B. Windows
C. UNIX
D. Linux

[单项选择]电脑启动后，屏幕上出现“Error loading operating system”的提示信息，无法正常启动，可能的故障原因是 (14) 。
A. 数据线连接错误
B. 电源接触不良
C. 硬盘被烧坏
D. 硬盘中系统引导文件被破坏

[单项选择]Thanks to the new online system, employees can order office stationery ______ rather than going through the office manager.
A. it
B. itself
C. them
D. themselves

[单项选择]

Online services are managed by a host system that maintains a base of information available to satellite users. Users of so-called "dumb" terminals (i. e., those without processing capability)simply access the information base via programs stored on the system. Personal computer (PC) users typically access the host through a modem (调制解调器). A PC software program serves as an interface (接口)between the server and a PC, allowing the user to operate through the online system and select different databases using a keyboard or a mouse.
National and regional online systems usually have local telephone numbers that PC modems can call to access either a local information base or an indirect long-distance connection, thus reducing long-distance telephone fees. Some online systems allow users ’to copy large volumes of information onto a local memory storage device, which also reduces the time the user is connected to the online system.
Besides offering
A. seek for a large mount of information
B. be connected to various databases
C. be introduced by the local library
D. pay a monthly membership fee