单选题在关系模型的完整性约束中,实体完整性规则是指关系中
31
,而参照完整性(即引用完整性)规则要求
32
。
单选题如果数据库应用系统的用户表中存有用户登录口令,则应该
________
。
单选题在某超市里有一个收银员,且同时最多允许有n个顾客购物,我们可以将顾客和收银员看成是两类不同的进程,且工作流程如图5-4所示。为了利用P-V操作正确地协调这两类进程之间的工作,设置了三个信号量S1、S2和Sn,且初值分别为0,0和n。这样图中的口应填写(46),图中的b1,b2应分别填写(47),图中的c1,c2应分别填写(48)。
单选题
11.设计高质量的软件是软件设计追求的一个重要目标。可移植性、可维护性、可靠性、效率、可理解性和可使用性等都是评价软件质量的重要方面。
可移植性是指将一个原先在某种特定的硬件或软件环境下正常运行的软件移植到另一个硬件或软件的环境下,使得该软件也能正确运行的难易程度。为了提高软件的可移植性,应注意提高软件的{{U}}
(1) {{/U}}。 可维护性通常包括{{U}} (2) {{/U}}。通常认为,软件维护工作包括正确性维护、{{U}} (3)
{{/U}}维护和{{U}} (4) {{/U}}维护。其中{{U}} (5) {{/U}}维护则是为了扩充软件的功能或者提高原有软件的性能而进行的维护活动。
(5) 是指当系统万一遇到未预料的情况时,能够按照预定的方式来作合适的处理。
单选题The purpose of the requirements definition phase is to produce a clear, complete, consistent, and testable (6) of the technical requirements for the software product. During the requirements definition phase, the requirements definition team uses an iterative process to expand a broad statement of the system requirements into a complete and detailed specification of each function that the software must perform and each (7) that it must meet. The starting point is usually a set of high-level requirements from the (8) that describe the project or problem. In either case, the requirements definition team formulates an overall concept for the system and then defines (9) showing how the system will be operated, publishes the system and operations concept document, and conducts a system concept review (SCR). Following the SCR, the team derives (10) requirements for the system from the high level requirements and the system and operations concept. Using structured or object-oriented analysis the team specifies the software functions and algorithms needed to, satisfy each detailed requirement.
单选题软件测试的一项重要作业是设计测试用例。测试用例主要由输入数据和
25
两部分组成。测试用例的设计方法主要有黑盒方法和白盒方法。黑盒方法根据程序的
26
设计测试用例,而白盒方法则根据程序的
27
设计测试用例。单独测试一个模块时,有时需要有一个
28
程序
28
被测试的模块。有时还要一个或者几个
30
模块模拟由被测试模块调用的模块。
单选题高速缓存Cache与主存间采用全相联地址映像方式,高速缓存的容量为4MB,分为 4块,每块IMB,主存容量为256MB。若主存读写时间为30ns,高速缓存的读写时间为3ns,平均读写时间为3.27ns,则该高速缓存的命中率为
24
%。若地址变换表如下所示,则主存地址为8888888H时,高速缓存地址为
25
H。
地址变换表
0
38H
1
88H
2
59H
3
67H
单选题DOM is a platform-and language- (11) API that allows programs and scripts to dynamically access and update the content, structure and style of WWW documents (currently, definitions for HTML and XML documents are part of the specification). The document can be further processed and the results of that processing can be incorporated back into the presented (12) . DOM is a (13) -based API to documents, which requires the whole document to be represented in (14) while processing, it. A simpler alternative to DOM is the event-based SAX, which can be used to process very large (15) documents that do not fit info the memory available for processing.
单选题在文件存储设备管理中,有三类常用的空闲块管理方法,即位图向量法、空闲块链表链接法和 (49) 。
单选题
20.IS09000系列标准和软件成熟度模型CMM都着眼于质量和过程管理。IS09000系列标准的主导思想是:强调质量{{U}} (1)
{{/U}};使影响产品质量的全部因素始终处于{{U}} (2) {{/U}}状态;要求证实企业具有持续提供符合要求产品的{{U}} (3)
{{/U}};强调质量管理必须始终坚持进行质量{{U}} (4) {{/U}}。而CMM则强调持续的{{U}} (5)
{{/U}}。
单选题某系统中有四种互斥资源R1、R2、R3和R4,可用资源数分别为3、5、6和8。假设在T0时刻有P1、P2、P3和P4四个进程,并且这些进程对资源的最大需求量和已分配资源数如表5-6所示,那么在T0时刻系统中R1、R2、R3和R4的剩余资源数分别为(20)。如果从T0时刻开始进程按(21)顺序逐个调度执行,那么系统状态是安全的。
单选题下列公式中一定成立的是______。
单选题设计制作一个多媒体地图导航系统,使其能根据用户需求缩放地图并自动搜索路径,最适合的地图数据应该是 (17) 。
单选题要使用户张先生只能查询表A中的部分记录,应采取的策略是 (6) 。
单选题With the widespread use of the personal computer, many authorities in the field of (56) have pointed out the need for computer literacy. Unfortunately, there is no (57) agreement as to what the term "computer literacy" means. Some feel that computer literacy means knowing how to make the computer "compute"; that is knowing how to program computers in one or more programming languages. Others feel that knowing how to program is merely a small segment of computer literacy. These people (58) the major emphasis in schools should be on teaching how to effectively use the many software packages that are available. Still others suggest that computer literacy education is not required. They suggest that computers are being so rapidly integrated into our society that using a computer will be as (59) as using a telephone or a video tape recorder, and that special education will not be necessary. (60) of one's definition of computer literacy, it is recognized by most that learning to use a computer is indeed an important skill in modern society.
单选题
30.大容量的辅助存储器常采用RAID磁盘阵列。RAID的工业标准共有6级。其中{{U}} (1)
{{/U}}是镜像磁盘阵列,具有最高的安全性;{{U}} (2) {{/U}}是无独立校验盘的奇偶校验码磁盘阵列;{{U}} (3) {{/U}}是采用纠错海明码的磁盘阵列;{{U}}
(4)
{{/U}}则是无冗余也无校验的磁盘阵列,它采用了数据分块技术,具有最高的:I/O性能和磁盘空间利用率,比较容易管理,但没有容错能力。
单选题“日志”文件用于保存______。
单选题关于ARP表,以下描述中正确的是
________
。
单选题在内排序的过程中,通常需要对待排序的关键码集合进行多遍扫描。采用不同排序方法,会产生不同的排序中间结果。设要将序列Q,H,C,Y,P,A,M,S,R,D,F, X中的关键码按字母的升序重新排列,则 (24) 是冒泡排序一趟扫描的结果, (25) 是初始步长为4的希尔排序一趟扫描的结果, (26) 是两路归并(合并)排序一趟扫描的结果, (27) 是以第一个元素为分界元素的快速排序一趟扫描的结果, (28) 是堆排序初始建堆的结果。
单选题在段页式管理的存储器中,实存等分为
32
、程序按逻辑模块分成
33