| 软件水平考试系统分析师易错题（2018/10/3） |
| 第1题：局域网常用的拓扑结构有总线、环形、星形3种，以下关于这3种拓扑结构说法错误的是( )
A、总线网可靠性高、扩充性能好、通信电缆长度短、成本低，但当网上站点较多时会因数据冲突增多而使效率降低 B、环形网控制简单、信道利用率高通信电缆长度短、对节点接口和传输的要求较低但存在数据冲突问题 C、星形网结构简单、实现容易、信息延迟确定，但通信电缆总长度长、传输媒体不能共享 D、选用何种拓扑结构，首先要考虑采用何种媒体访问控制方法，其次要考虑性能、可靠性、成本、扩充性、实现难易以及传输媒体的长度等因素 |
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| 第2题：虚拟存储器的最大容量( )
A、为主辅存容量之和 B、由计算机的地址结构决定 C、是任意的 D、由作业的地址空间决定 |
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| 第3题：软件工程方法的产生源于软件危机，下列( )是产生软件危机的内在原因
I 软件复杂性 II 软件维护困难 III 软件成本太高 IV 软件质量难保证 A、I B、III C、I和IV D、III和IV |
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| 第4、5、6、7、8题：In the following essay, each bland has four choices.Choose the best answer and write down on the answer sheet. With the implementation of (6) the so – called network has become a reality. The provision of such facilities is the most important part of the network requirements. However, in many applications the communicating computers may be of different types. This means that they may use different programming languages and, more importantly, different forms of (7) interface between user(application)program, normally referred to ,as application processes, and the underlying communication services may be (8). For example, one computer may be a small single-user computer, while another may be a large (9) system. In the earlier days of computer communication, these issues meant that only closed communities of computers (that is, from the same manufacturer) could communicate with each other in a meaningful way. IBM’s systems NetworkArchitecture (SNA、andDEC’sDigital NetworkArchitectureDNA、are just two examples of communication software packages produced by manufacturers to allow their systems to be intercormected together. These proprietary packages, however, of which there am still many inexistence, do not address the problem of universal interconnect ability, or open systems interconnection. In an attempt to alleviate this problem,(10) ,in the late 1970s,formulated a reference model to provide a common basis (or the coordination of standards developments and to allow existing and evolving standards activities to be placed into perspective with one another.
(6) A、communicationchannel B、protocols C、datachannel D、publiccommunication (7) A、database B、datarepresentation C、protocols D、datacommunication (8) A、same B、similar C、different D、dependent (9) A、multi-user B、client C、server D、full-user (10) A、DNA B、SNA C、theOSI D、theISO |
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| 第9题：如果对一个关系实施了一种关系运算后得到了一个新的关系，而且新的关系中的属性由该运算决定，这说明所实施的运算关系是( )
A、选择 B、投影 C、连接 D、笛卡儿积 |
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