Like a commercial CD found in music stores, a CD-ROM is a “read-only” disc.
Read-only means it cannot be written on or erased by the user. Thus, you as a user have
access only to the data imprinted (压印) by the publisher.
A single CD-ROM disc can store 650 megabytes (兆字节) of data. That is equivalent to
451 floppy disks. With that much information on a single disc, the time to retrieve or access
the information is very important. An important characteristic of CD-ROM drives is their access rate.
IV. Translate the following passage from English into Chinese:
调制解调器是在 模拟和数字信号之间进行转换的设备。计算机使用的是数字信号，
这种信号由离散单元组成，通常用一系列1和0表示。模拟信号是连续变化的；声 波就是
模拟信号的一个例子。调制解调器经常用于实现计算机之间通过电话线的互相通信。调
制解调器将发送端计算机的数字信号转 换成可通过电话线传输的模拟信号。信号到达目
的地后，另外一个调制解调器重构原来的数字信号，供接收端计算机处理。如果两个调
制 解调器可同时互相发送数据，那么它们采用的就是全双工工作方式；如果一次只有一
个调制解调器可以发送数据，那么它们采用的则是半双工工作方 式。
Unit Two/Section B
I. Fill in the blanks with the information given in the text: 1. graphical 2. file; scheduler 3. virtual
4. slice
II. Translate the following terms or phrases from English into Chinese and vice versa: 1. interrupt handler 中断处理程序
2. virtual memory 虚拟存储（器），虚存，虚拟内存 3. context switch 上下文转换，语境转换 4. main memory 主存（储器） 5. bit pattern 位模式
6. 外围设备 peripheral device 7. 进程表 process table 8. 时间片 time slice
9. 图形用户界面 graphical user interface 10. 海量存储器 mass storage Unit Two/Section C
I. Fill in the blanks with the information given in the text:
1. repository
2. central; sub-systems 3. network
4. layered或abstract machine
II. Translate the following terms or phrases from English into Chinese and vice versa: 1. code generator 代码生成程序，代码发生器 2. abstract machine 抽象机
3. program editor 程序编辑程序，程序编辑器 4. configuration item 配置项
5. 计算机辅助设计 CAD (computer-aided design) 6. 数据冗余 data redundancy
7. 指挥与控制系统 command and control system 8. 视频压缩与解压缩 video compression and decompression
Unit Three: Computer Language and Programming
Unit Three/Section A
I. Fill in the blanks with the information given in the text:
1. artificial; instructions 2. low-level; high-level 3. machine 4. machine
5. functional; logic 6. statement 7. module 8. digital
II. Translate the following terms or phrases from English into Chinese and vice versa: 1. storage register 存储寄存器 2. function statement 函数语句 3. program statement 程序语句