[Ex. 5]
Bus Systems Supporting Multiple Peripherals
As the number of potential peripherals grew, using an expansion card for every peripheral became increasingly impossible. This has led to the introduction of bus systems designed specifically to support multiple peripherals. Common examples are the SATA ports in modern computers, which allow a number of hard drives to be connected without the need for a card. However, these high-performance systems are generally too expensive to implement in low-end devices, like a mouse. This has led to the parallel development of a number of low-performance bus systems for these solutions, the most common example being Universal Serial Bus. All such examples may be referred to as peripheral buses, although this terminology is not universal. Notes:
1. Serial ATA (SATA) is a computer bus interface for connecting host bus adapters to mass storage devices such as hard disk drives and optical drives.
2. Universal Serial Bus USB
支持多种外接设备的总线系统
随着外接设备数量的不断增加，想用扩展卡来应付每一种外围设备越来越不现实了，这就产生了设计专门支持多种外接设备的总线系统。通常的例子就是现代计算机上的SATA接口，这就允许很多硬盘驱动器不需要卡就可以同计算机连接
起来。但是把这些高性能系统用于低端设备，如鼠标等就很不合算。这就导致同时开发很多低性能的总线系统解决方案，最常见的例子就是UBS接口。所有这些例子都可以称作外接设备总线，尽管这个术语还没有普遍通用。
[Ex 6] 1. T 2. F 3. F 4. T 5. T 6. F 7. T 8. T 9. T 10 F Unit 4
[Ex 1] 1. F 2. T 3. T 4. T 5. F 6. T 7. F 8. T 9. T 10. T 11. F 12. T
13. F 14. T 15. T 16. F 17. F 18. T 19. F 20. T 21. F
22. T
23. F 24. T 25. F
[Ex 2] 1. main memory 2. RAM 3. diskettes/floppy disks; hard disks 4. chips 5. parity 6. expanded, extended 7. monochrome 8. cache 9. ROM 10. updated
[Ex 3] A. 1. B 2. E 3. C 4. J 5. I 6. H 7. A 8. F 9. G 10 D
B. 1. secondary storage 2. buffer 3. access 4. code 5.
diskette
6. slots 7. terminals 8. motherboard 9. bytes 10. screen
[Ex 4] 1. desktop 2. software 3. animation 4. transferred 5. sophisticated
6. compatible 7. cache 8. upgrade
[Ex 5]
USB flash drive
A USB flash drive is a data storage device that includes flash memory with an integrated Universal Serial Bus (USB) interface. USB flash drives are typically removable and rewritable, and physically much smaller than a floppy disk. Most weigh less than 30 g. As of September 2011, drives of up to 256 gigabytes (GB) are available. Storage capacities as large as 2 terabytes are planned, with steady improvements in size and price per capacity expected. Some allow up to 100,000 write/erase cycles, depending on the exact type of memory chip used, and a 10 year shelf storage time.
USB flash drives are often used for the same purposes for which floppy disks or CD-ROMs were used, i.e., for storage, back-up and transfer of computer files. They are smaller, faster, have thousands of times more capacity, and are more durable and reliable because they have no moving parts. Until about 2005, most desktop and laptop computers were supplied with floppy disk drives, but floppy disk drives have been abandoned in favor of USB ports.
Notes
GB: gigabyte 吉字节 109 字节； terabyte TB 太字节，1012 字节
USB闪驱
USB闪驱是一种数据存储设备，它包含带有一个集成的通用串行总线（USB）接口 。USB闪驱通常可以移动并可以重写，其尺寸要比软盘小得多，大多数的重量不到30克。从2011年9月始，市场就出现256 GB的U盘。2太字节的U盘在筹划之中，估计U盘大小会更加合理，价格也更合适。有的U盘允许写/擦10万个循环，这取决于存储芯片的型号，储存寿命可以达到10年时间。
USB闪驱与软盘或CD-ROM的目的相同，就是为了计算机文件的存储、备份和转移。因为它们没有移动部件，所以体积更小，速度更快，拥有数千倍的容量，更加持久可靠。到2005年，大部分台式和膝上电脑还都配备软驱，但是软驱因为USB插口而被淘汰。
[Ex. 6] 1. T 2. F 3. F 4. T 5. T 6. T 7. T 8. F 9. F 10. F
11. T 12. T 13. T 14. F 15. T 16. F 17. T 18. T 19. F
20. T 21. T 22. T
Unit 5
[Ex 1] 1. T 2. T 3. F 4. T 5. F 6. F 7. F 8. T 9. T 10. T 11.
F 12. T 13. F 14. F 15. T 16. T 17. F 18. T 19. F 20. F 21. T 22. T 23. T
[Ex 2] 1. mail, courier 2. hub, star 3. Local Area Network 4. packets 5. Ethernet
6. kilobits per second, megabits per second, gigabits per second 7. circuit switching 8. reassembled 9. Internet Protocol, Transmission Control Protocol 10. datagram 11. frames 12. binary, decimal
[Ex 3] A. 1. C 2. E 3. B 4. F 5. A 6. D 7. H 8. G B. 1. hub 2. zipped 3. decimal 4. frame
5. binary number 6. Internet 7. packet 8. bandwidth [Ex 4] 1. forwarded 2. reassembled 3. are encapsulated 4. cables 5. bursty
6. submit 7. are retransmitted 8. protocol [Ex 5]
1. E 2. A 3. C 4. F 5. B 6. D 7. H 8. G
[Ex 6]
1. 有意为技术服务人员留下的
2. 抛弃、丢失或毁灭的数据都进入到数据接受器中
3. 远远不能覆盖绝大多数嫌疑人 4. 真正奇才所掌握的技术 5. 文件和程序
6. 1. 系统详情、扩展其性能 5. 敏感信息的人 7. 滞缓的特性和控制开发的复杂性
8. 非常巧妙的权宜之计，旨在解决很棘手的问题 9. 不能有效与他人沟通的人
10. 一个程序、数据结构或全部程序的 11. 交叉指向不合适的新闻组
12. 打免费长途电话了；通信网络，但不单指通信网络 13. 眼睛疲劳
14. 无关紧要或令人讨厌的琐碎问题
15. 不会有人发现这些漏洞的，或发现了也不会利用 16. 受人雇佣，为测试系统的安全性而攻入某个地方
17. 那种使用许多GOTO、例外或另外的“非结构的”分支构造 18. 不能定期运行适当的抑制程序 19. 某种非常友好程序的 20. 远在没有正式发行之前
21. 该技术也许不能发挥作用。如果不能用，程序员也永远不知道为什么 22. Suns 机上使用L1-A；某些Mac机使用!
23. 完全丧失功能了；计算机想做某事但不能进行下去了
24. 人的神经系统，与计算机的硬件或软件相对；系统的硬件或软件
计算机专业英语教程第四版习题答案
