单选题进程Pl.P2.P3.P4和P5的前趋图如下图所示：
若用PV操作控制进程P1.P2.P3.P4和P5并发执行的过程，则需要设置5个信号量S1.S2.S3.S4和S5，且信号量SI～S5的初值都等于零。下图中a和b处应分别填写（ ）；c和d处应分别填写（ ），e和f处应分别填写（ ）
。
单选题E-R 图中的组合属性应转换为对象－关系数据模型中的 （62） 。
单选题SMTP传输的邮件报文采用______格式表示上。
单选题Currently the Pentium chip or (71) , made by (72) , is the most common CPU though there are many other companies that produce processors for personal computers. One example is the CPU made by Motorola which is used in Apple computers. With faster processors the clock speed becomes more important. Compared to some of the first computers which operated at below 30 megahertz ( (73) ) the Pentium chips began at 75 megahertz in the late 1990g. As of mid 2003 speeds now exceed 3000 + megahertz or 3 gigahertz (check your local computer store for the latest speed) . It depends on the (74) that the chip is housed in, or the (75) , as to whether you are able to upgrade to a faster chip. The motherboard contains the circuitry and connections that allow the various component to communicate with each other.
单选题需求分析阶段要生成的文档是 （53） 和数据字典。
单选题（ ）是构成我国保护计算机软件著作权的两个基本法律文件
单选题如果系统采用信箱通信方式，当进程调用Send原语被设置成“等信箱”状态时，其原因是______。
单选题以下关于程序设计语言的叙述中，错误的是______。
单选题 ARP协议属于{{U}} {{U}} 66 {{/U}}
{{/U}}协议，它的作用是{{U}} {{U}} 67 {{/U}} {{/U}}。
单选题Basically，a firewall if a ______ process or a set of integrated processes that runs on a router or______ to control the flow of networked application traffic!______ through it．Typically，firewallsare placed on the entry point to a ______ network such as the Internet．They could be consideredtraffic cops．The firewall"s ______ is to ensure that all communication between an organization"snetwork and the intemet conform to the organization"s security policies．
单选题给定关系模式销售排名(员工号，商品号，排名)，若每一名员工每种商品有一定的排名，每种商品每一排名只有一名员工，则以下叙述中错误的是_______。
单选题分段管理的主要优点是： (23) 。
单选题在虚拟分页存储管理系统中，若进程访问的页面不在主存，且主存中没有可用的空闲块时，系统正确的处理顺序为 (25) 。
单选题若将 Workers 表的插入权限赋予用户 User1，并允许其将该权限授予他人，那么对应的SQL 语句为GRANT（ ） TABLE Workers TO User（ ）；
单选题给定关系模式R(U，F)，U={A，B，C，D}，函数依赖集F={AB→C，CD→B}。关系模式R______，且分别有______。若将R分解为ρ={R
1
(ABC)，R
2
(CDB)}，则分解ρ______。
单选题The entity-relationship (E-R) data model is based on a perception of a real world that consists of a collection of basic objects, called（ ），and of relationships among these objects
单选题嵌入式SQL语句的执行状态通过______传递给主语言来进行流程控制。 A．主变量 B．游标 C．SQLCA D．数据集
单选题
单选题Most computer systems are
17
to two different groups of attacks: Insider attacks and outsider attacks. A system that is known to be
18
to an outsider attack by preventing
19
from outside can still be vulnerable to the insider attacks accomplished by abusive usage of
20
users. Detecting such abusive usage as well as attacks by outsides not only provides information on damage assessment, but also helps to prevent future attacks. These attacks are usually
21
by tools referred to as Intrusion Detection Systems.