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1、Computer EnglishChapter 1 Computer Hardware第一章第一章 计算机硬件计算机硬件1Computer EnglishLesson one An Overview of Computer System第一课第一课 计算机系统概述计算机系统概述2An overview of Computer systemvKey Words:v term n. 术语v component n. 部件，构件v electromechanical adj.电子机械的v intelligence n. 智力，智能v combination n. 结合，合并v hardware n.
2、 硬件v software n. 软件v information n. 信息，情报，资料v procedure n. 程序，手续v connectivity n. 连通性v transmission n. 传送，传输v instructions n. 指示，指导，指令3An overview of Computer systemv perform vt. 履行，执行v operate v. 操作，运转v convert vt. 使转变，转换v unevaluated adj.未经估值的，未鉴定的v concept n. 观念，概念v process vt. 加工，处理v refining n.
3、 精练，提炼v inventory n. 存货，财产清册，总量v capture vt. 俘获，捕获，夺取v indicate vt. 指出，显示，预示v equipped v. 装备，配备v capacity n. 容量，能力v simultaneously adv.同时4An overview of Computer systemv We are changing from an industrial society to an information society. Personal computers are becoming as common as the telephone i
4、n both the workplace and our home. We live in an information age where the person or company with the latest information gains a strategic advantage. The computer has changed the way we live and work.v 我们正在从工业社会向信息社会转化。不论是在工作单位，还是在家中，个人计算机都已经像电话那样普及。在我们生活的信息时代，掌握了最新信息的人或公司就能在战略上获得优势。计算机已经改变了我们的生活和工作
5、方式。 5An overview of Computer systemv The term computer is used to describe a device made up of a combination of electronic and electromechanical （part electronic and part mechanical）components. By it self，a computer has no intelligence and is referred to as hardware. A computer doesnt come to life u
6、ntil it is connected to other parts of a computer system. A computer system is a combination of five elements（listed here in the order of how expensive it would be to replace them in a system，from least to most expensive）: v 计算机是用来描述由电子和电子机械（部分电子和部分机械）元件组合而成的一种设备。就其本身，计算机没有智力，因此可以称之为硬件。一台计算机如果不和计算机的
7、其他系统连接起来是不会有什么作为的。计算机系统由五大部分构成（下面按它们在系统中如需替换而要花钱的多少从低到高排序）: 6An overview of Computer systemv*Hardware v*Softwarev*Data/information v*Procedure v*Peoplev*硬件v*软件v*资料/信息 v*程序 v*人7An overview of Computer systemv When one computer system is set up to communicate with another computer system，connectivity
8、becomes a sixth system element. In other words，the manner in which the various individual systems are connectedfor example，by phone lines，microwave transmission or satelliteis an element of the total computer system.v 如果建立一个计算机系统的目的是为了与另一个计算机进行通信，那么连接就成了第六个系统成分。换句话说，将不同独立的系统通过电话线、微波传递或卫星等连接起来的形式也是整个
9、计算机系统的一个成分。 8An overview of Computer systemv Software is the term used to describe the instructions that tell the hardware how to perform a task; without software instructions，the hardware doesnt know what to do. People operate the computer hardware; they create the computer software instructions an
10、d respond to the procedures that those instructions present. You will learn more about software and procedures later. Right now we want to discuss the importance of data and information. v “软件”是用来描述要求计算机如何工作的指令的专门术语。没有软件指令，计算机就不知道该做什么。不过人们构造了计算机系统的最重要的部分，包括操作硬件，创建计算机软件指令并对这些指令的程序做出相应的反应。以后你学到更多的有关软件
11、和程序的知识。现在我们讨论数据和信息的重要性。 9An overview of Computer systemv The purpose of a computer system is to convert data into information. Data is raw，unevaluated facts and figures，concepts，or instructions. This raw material is processed into useful information. In other words，information is the product of data
12、 processing. This processing includes refining，summarizing，categorizing，and otherwise manipulating the data into a useful form for decision making. v 计算机系统的目的是将数据转换成信息。数据是原材料，没有经过任何的评价，包括数字、概念或指令。原材料要被加工成有用的信息。换句话说，信息是数据处理后的产品。这个处理过程包括提炼、归纳、分类，也就是将它们加工处理成便于决策的形式。10An overview of Computer systemvFor
13、example，the facts and figures contained in a stack of customer orders waiting to be entered into a computer-based order entry system are data; after the data is entered and processed，an output report about how that data affected product inventory would be information. v例如有待输入计算机处理系统的一堆用户订单上的情况和数字是数据
14、，等到把这些数据输入系统并进行加工处理后，输出的有关这些数据对产品存货所发生的影响的报告就变成了信息。11An overview of Computer systemv People “capture” data in a variety of waysfor example，by reading，listening，or seeing. Then they may record the data on a document. For instance，Roger Shu records his name on an employee timecard by first entering th
15、e letter R. This letter，and each of the remaining letters in his name，is an element of data，as are the numbers 12/22 and 5，used to indicate the date and the number of overtime hours worked. v 人们“捕捉”信息的办法各种各样，例如通过读、听或看，然后人们可以把数据记录在文件上。例如罗杰苏把自己的名字录到雇员卡上，首先录入字母R。这个字母及他名字中余下的每一个字母就像数字12/22和5一样是数据的一个成分，用
16、来表示日期和加班的时间。12An overview of Computer systemvBy themselves，these data elements are useless; we must process them to make them mean something. The report produced when Rogers data is running through a computer-based employee records system gives us informationfor example，the amount of money due Roger
17、 for his overtime work. v这些数据本身是没有什么意义的，我们必须对它们进行加工处理使它们具有一定的意义。当有关罗杰的数据经过计算机雇员记录系统的处理，产生的报告就提供给我们信息例如罗杰的加班工资总数。13An overview of Computer systemv In general, a computers type is determined by the following seven factors:v (1)The type of CPU. As noted，microcomputers use microprocessors. The larger co
18、mputers tend to use CPUs made up of separate，high-speed，sophisticated components. v 一般说来，计算机的类型由以下七大因素决定:v (1)CPU的型号。大家已经知道，微型计算机使用微处理器。较大计算机趋向于使用由单独的高速复杂的零部件构成的CPU。 14An overview of Computer systemv (2)The amount of main memory the CPU can use. A computer equipped with a large amount of main memory
19、 can support more sophisticated programs and can even hold several different programs in memory at the same time.v (3)The capacity of the storage devices. The larger computer systems tend to be equipped with higher capacity storage devices. v (2)CPU能够使用的主存的总量。配置大主存的计算机能够支持较高级的程序，甚至能在主存中同时容纳几个不同的程序。v
20、 (3)存储设备的容量。越大的计算机系统越趋向配置大容量的存储设备。 15An overview of Computer systemv （4）The speed of the output devices. The speed of microcomputer output devices tends to rated in terms of the number characters per second（cps）that can be printedusually in tens and hundreds of cps. Larger computers output devices a
21、re faster and are usually rated at speeds of hundreds or thousands of lines that can be printed per minute. v （4）输出设备的速度。微机输出设备的速度倾向于用每秒钟能打印的字符数（cps）来度量，通常每秒钟为几十个、几百个字符。较大计算机的输出设备的速度也较快，通常每分钟可打印几百或几千行。 16An overview of Computer systemv (5)The processing speed in millions of instruction per second（mi
22、ps）. The term instruction is used here to describe a basic task the software asks the computer to perform while also identifying the data to be affected. The processing speed of the smaller computers ranges from 7 to 40 mips. The speed of large computers can be 30 to 150 mips or more，and supercomput
23、ers can process more than 200 mips. In other words，a mainframe computer can process your data a great deal faster than a microcomputer can .v (5)用mips（每秒钟百万条指令）度量处理速度。“指令”这个概念在这儿用来描述软件所执行的基本任务，同时标识受到影响的数据。较小计算机的处理速度为740 mips。大型计算机的处理速度能达到30150 mips或更多。巨型计算机能处理200多mips。换句话说，大型计算机处理数据的能力要比微机快得多。 17An
24、overview of Computer systemv (6)The number of users that can access the computer at one time. Most small computers can support only a single user; some can support as many as two or three at a time. Large computers can support hundreds of users simultaneously.v (7) The cost of the computer system. B
25、usiness systems can cost as little as 500（for a microcomputer）or as much as 10 million（for a mainframe）and much more for a supercomputer. v (6)同时可以使用计算机的用户数。大部分小型计算机只能由单个用户使用，有些计算机可同时让两个或三个用户使用，大型计算机则同时可由几百个用户使用。v (7)计算机系统的价格。商用计算机系统的价格从只值五百美元（一台微机）到要开价一千万美元（一台主机），巨型计算机则花费更多。 18Computer EnglishLesso
26、n two The Central Processing Unit第二课第二课 中央处理单元中央处理单元19The Central Processing UnitThe Central Processing UnitvKey Words:v arithmetic n. 算术，运算v binary adj.双态的，二进制的v bus n. 总线，通信通路v circuitry n. 电路v configuration n. 配置，结构，形状，布置v convert vt. 转换v decode vt. 译码，解码v logic n. 逻辑（线路）v microsecond n. 微秒，百万分之一
27、秒 20The Central Processing UnitThe Central Processing UnitvKey Words:v millisecond n. 毫秒，千分之一秒v multiply v. 乘，做乘法v nanosecond n. 纳秒，十亿分之一秒v picosecond n. 皮秒，万亿分之一秒v register n. 寄存器，注册v retrieval n. 检索，取回，恢复v synchronize v. 同步发生，同步v transfer v. 传送，转移，传输，转换v transmit v. 传送，传输v wordsize n. 字长21The Cent
28、ral Processing UnitThe Central Processing Unitv The central processing unit（CPU）is the heart of the computer system. Among other things， its configuration determines whether a computer is fast or slow in relation to other computers. The CPU is the most complex computer system component，responsible f
29、or directing most of the computer system activities based on the instructions provided. v 中央处理器（CPU）是计算机系统的心脏。一台计算机相对于其他计算机的速度是快还是慢，除了别的因素外，CPU的配置起着决定的作用。CPU是最复杂的计算机系统设备，它根据提供的指令负责指挥协调计算机系统的全部活动。22The Central Processing UnitThe Central Processing UnitvAs one computer generation has evolved to the ne
30、xt，the physical size of the CPU has often become smaller and smaller，while its speed and capacity have increased tremendously. Indeed，these changes resulted in microcomputers that are small enough to fit on your desk or your lap. The CPU circuitry of a microcomputercalled a microprocessor can fit on
31、 a chip about the size of your thumbnail，or even smaller. v当老一代计算机被新的一代计算机替代的时候，CPU的实际尺寸往往变得越来越小，而其速度和性能却有了惊人的增长。这种变化的结果就使得微机缩小得可以放在你的桌上或膝盖上。微机的CPU电路即微处理器可以安置在像大拇指那么大甚至更小的芯片上23The Central Processing UnitThe Central Processing Unitv The CPU has two main parts: the control unit and the arithmetic/logi
32、c unit . The parts of the CPU are usually connected by an electronic component referred to as a bus，which acts as an electronic highway between them. To temporarily store data and instructions，the CPU has special-purpose storage devices called registers. v CPU有两个主要部件:控制单元和算术/逻辑单元。CPU的部件通常由称为总线的电子设备连
33、接，总线在它们之间充当着电子交通干线的角色。为了临时存储数据和指令，CPU有一个专门用于存储的设备，叫作寄存器。 24The Central Processing UnitThe Central Processing Unitv 1.Control Unitv The control unit，a maze of complex electronic circuitry，is responsible for directing and coordinating most of the computer system activities. It does not execute instruc
34、tions itself; it tells other parts of the computer system what to do. It determines the movement of electronic signals between main memory and the arithmetic/logic unit，as well as the control signals between the CPU and input /output devices.v 1.控制单元v 控制单元是一个复杂的电路迷宫，担负着指挥和协调大多数计算机系统活动的职责。它本身并不执行任何指令
35、，只安排计算机系统的其他部件去工作。它决定主存和算术/逻辑单元间电信号的流动，也决定着CPU和输入/输出系统设备之间控制信号的流动。 25The Central Processing UnitThe Central Processing Unitv Just as a car is useless without gas，a computer is not much good without software instructions. When we use software，we are working with high-level（human language-like）instruc
36、tions that are to be carried out by the control unit. These instructions are converted by a language processor into a low level form of instructions the computer can work withmachine language，the only language that the CPU can understand. v 正如汽车没有油就不能发挥任何作用一样，计算机如果没有软件指令也就一事无成。我们使用软件时，用的是控制单元将要执行的高级
37、指令（就像人类的语言一样）。语言处理器将这些指令转换成计算机可以用来工作的低级指令形式，即CPU唯一能够理解的机器语言。26The Central Processing UnitThe Central Processing UnitvIn machine language，data and instructions are represented in binary form（0s and 1s），and each type of computermicrocomputer，minicomputer，or mainframeresponds to a unique version of mac
38、hine language. Once the instructions have been converted into this form，they can be retrieved from main memory and interpreted by the control unit（sometimes referred to as decoding）.v在机器语言中，数据和指令都用二进制的形式（0和1）表示，每一种类型的计算机-微机、小型计算机或大型计算机-都只对与其相配的机器语言做出响应。一旦指令被转换成机器语言形式，控制单元就能从主存中将它们检索出来并且负责解释（有时候也称为“译
39、码”）。27The Central Processing UnitThe Central Processing UnitvAccording to each specific instruction，the control unit issues the necessary signals to other computer system components as needed to satisfy the processing require ments. This could involve，for example，directing that data be retrieved fro
40、m a disk storage device ，“telling” the printer to print the letter you just wrote，or simply directing the arithmetic/logic unit to add two numbers.v根据每项具体指令，控制单元向计算机系统其他部件发出它们所需的信号来满足处理的需求。这可能涉及诸如命令从磁盘存储设备中检索数据、通知打印机打印你刚刚写好的信件或者仅命令算术/逻辑单元把两个数字相加。28The Central Processing UnitThe Central Processing Un
41、itv 2.Arithmetic/Logic Unit（ALU） Without the arithmetic/logic unit（ALU），the Kim program would not be able to do those financial forecasts for Sporting Life on the computer，and you would not be able to use Ticketron to find out if you and your friends can get five seats at the Lemon Bowl. In fact，wit
42、hout the ALU， computers would not be able to do most of the tasks that we find useful. The ALU performs all the arithmetic and logical（comparison）functionsthat is，it adds，subtracts，multiplies，divides， and does comparisons. 2.算术/逻辑单元（ALU） 没有算术/逻辑单元（ALU），Kim程序就不能在计算机上给体育生活（Sporting Life）杂志提供财经预报，你也不能用
43、Ticketron程序来断定你和你的朋友是否能买到雷盟体育场（Lemon Bowl）的五张票。事实上，没有算术/逻辑单元，计算机就无法完成我们认为有用的很多工作。ALU完成所有的算术和逻辑（比较）功能如加、减、乘、除，以及进行各种比较. 29The Central Processing UnitThe Central Processing UnitvThese comparisons，which are basically “less than”，“grater than”，and “equal to”，can be combined into several common expressio
44、ns，such as “greater than or equal to”. The objective of most instructions that use comparisons is to determine which instruction should be executed next.v这些基本上是“小于”、“大于”和 “等于”的比较可以组合成几个常用的短语，如“大于或等于”。用于比较的大多数指令的目的是决定哪条指令是接下来要执行。 30The Central Processing UnitThe Central Processing Unitv The ALU contr
45、ols the speed of calculations and so receives a great deal of attention from computer engineers trying to meet the needs of the fast-paced business world. Older microcomputers speeds are usually measured in milliseconds1 thousandth of a second. Newer microcomputers speeds are measured in microsecond
46、s1 millionth of a second. Larger，powerful computers speeds are measured in nanoseconds1 billionth of a secondor picoseconds1 trillionth of a second. If a nanosecond were equal to one minute，then a minute would be equal to 1900 years!v ALU控制计算的速度，因此那些努力想满足商界快速运算需求的计算机工程师特别注意它。过去微型计算机的速度通常用毫秒（millisec
47、onds）即千分之一秒来度量，如今的微型计算机的速度用微秒（microseconds）即百万分之一秒来度量。大型计算机的速度用纳秒（nanoseconds）即十亿分之一秒，或用皮（可）秒（picoseconds）即万亿分之一秒来度量。假如一纳秒等于一分钟，那么一分钟就相当于1900年。31The Central Processing UnitThe Central Processing Unitv 3.Registers Registers are special temporary storage locations within the CPUsome in the control uni
48、t and some in the ALU. Registers very quickly accept，store，and transfer data and instructions that are being used immediately（Main memory holds data that will be used shortly; secondary storagesuch as a disketteholds data that will be used later）.To execute an instruction，the control unit of the CPU
49、 retrieves it from main memory and places it into a register. The typical operations that take place in the processing of instructions are part of either the instruction cycle or the execution cycle. 3.寄存器 寄存器是CPU中专门用于临时存储的场所，一部分在控制单元里，一部分在ALU当中。寄存器迅速接受、存储并传送即将使用的数据和指令（主存存放马上就要使用的数据，辅助存储器如磁盘存放以后使用的数
50、据）。如果要执行一条指令，CPU的控制单元要将其从主存中检索出来，然后将它放置到寄存器中。处理指令的典型操作由两部分组成:一是指令周期，二是执行周期。32The Central Processing UnitThe Central Processing Unitv The instruction cycle，or I-cycle，refers to the retrieval of an instruction from main memory and its subsequent decoding（the process of alerting the circuits in the CPU
51、 to perform the specified operation）.The time it takes to go through the instruction cycle is referred to as I-time. v 指令周期，也叫作I-cycle，指的是从主存中检索指令以及随后的译码（在CPU中使电路做好准备以执行专门操作的过程）。指令周期所需的时间叫作I-time。33The Central Processing UnitThe Central Processing Unitv The execution cycle，or E-cycle，refers to the e
52、xecution of the instruction and the subsequent storing of the result in a register. The time it takes to go through the execution cycle is referred to as E-time. The instruction cycle and the execution cycle together，as they apply to one instruction， are referred to as a machine cycle. The CPU has a
53、n internal clock that synchronizes all operations in the cycle. The speed is expressed in megahertz（MHz）;1 MHz equals 1 million cycles per second. Generally，the faster the clock speed，the faster the computer can process information. Of course，for most users，the faster, the better and the more expens
54、ive! v 执行周期，也叫作E-cycle，指的是执行这个指令以及随后将结果存放到寄存器的过程。执行周期所需的时间叫作E-time。由于指令周期和执行周期适合于同一条指令，因此合在一起称为机器周期。CPU内部有使周期中的所有操作同步的时钟，其速度用兆赫（MHz）表示。1 MHz相当于一百万周期每秒。一般来说，时钟的速度越快，计算机处理信息的速度也就越快。当然，对于大多数用户来说，速度越快越好，但意味着价钱也就越贵!34The Central Processing UnitThe Central Processing Unitv The number and types of register
55、s in a CPU vary according to the CPUs design. Their size（capacity）and number can dramatically affect the processing power of a computer system. In general， the “larger” the register，the more bits can be processed at once. The size of a register is referred to as wordsize.v CPU中寄存器的数量和类型根据CPU的设计而变化。寄
56、存器的大小（能力）和数量能够显著地影响计算机系统的处理能力。一般说来，寄存器越大，每次能够处理的位数也就越多。寄存器的大小通常称作字长。35The Central Processing UnitThe Central Processing Unitv Some personal computers have general-purpose registers that hold only 8 bits; other hold 16 bits; newer microcomputer have 32-bit registers. Computers that handle a 32-bit wo
57、rdsize can process data twice as fast as those that handle a 16-bit wordsize. The difference in processing power due to difference in register size can be illustrated by the difference between trying to put out a fire with a small drinking glass and with a 5-gallon bucket. v一些个人计算机配置的是通用寄存器，这类寄存器能够容
58、纳8位，另一些是16位，更新的微机有32位的寄存器。能够处理32位字长的计算机的处理速度是能够处理16位字长计算机的两倍。由于寄存器大小的不同而引起的处理能力的差异可以用一个比喻来说明:用一只水杯去救火和用5加仑的大水桶去救火是不一样的。 36The Central Processing UnitThe Central Processing Unitv 4.Bus The term bus refers to an electrical pathway through which bits are transmitted between the various computer compone
59、nts. Depending on the design of a system，several types of buses may be present. For the user，the most important one is the data bus，which carries data throughout the CPU. The wider the data bus，the more data it can carry at one time and thus the greater the processing speed of the computer. 4.总线 总线指
60、的是二进数码在各种计算机部件之间传送的电子通道。依据系统的设计，有几种类型的总线。对于用户来说，最重要的是数据总线，因为是它把数据传送给CPU。数据总线越宽，每次传送的数据就越多，因此计算机的处理速度也就越快。37Computer EnglishLesson Three Main memory第三课第三课 主存主存38Main memoryvKey Words：v architecture n. 结构，构造，体系结构v bank n. 存储单元v bit n. 比特，（二进制）位v buffer n. 缓冲器，缓冲，缓冲区v cabinet n. 机箱v cache n. 高速缓存v comm
61、unication n. 交流，通信v compatible adj.可兼容的，可共存的，兼容的v derive（from） v. 起源，由来v detection n. 检测v efficiently adv.有效的v erasable adj.可抹去的，可擦除的 39Main memoryv erroneously adj.错误地v firmware n. 固件，硬件v insert v. 插入v install v. 安装，装配v interpretation n. 解释v model n. 模型，样机，型号v monochrome n. 单色v nonvolatile adj.不变的，
62、稳定的，非易失性的v parity n. 奇偶，奇偶性，奇偶校验v plug v. （电器）插头，插入v screwdriver n. 螺丝刀v slot n. 槽v terminal n. 终端，端子，终端仿真程序v upgrade v. 使升级，更新40Main memoryv 1.Function of main memoryv The principal function of main memory is to act as an intermediary between the central processing unit（CPU）and the rest of the comp
63、uter system components. It functions as a sort of desktop on which you place the things with which you are about to begin to work. The CPU can utilize only those software instructions and data that are stored in main memory.v 1.主存的功能v 主存主要是在中央处理器（CPU）和计算机系统的其他部件之间充当中介作用。它类似一个桌面，你可以把急需处理的东西放在上面。CPU只能
64、利用存放在主存中的那些软件指令及数据。41Main memoryv As you know，main memory is random access memory，or RAM. The name derives from the fact that data can be stored in and retrieved at randomfrom anywherein the electronic main memory chips in approximately the same amount of time，no matter where the data is.v 正如你已经知道的，
65、主存是随机存取存储器，或者叫作RAM。这个命名是鉴于这么一个事实:数据在电子主存芯片中可以随意随处存放和检索，而且不管数据在何处，存放和检索的时间差不多是相同的。42Main memoryv Main memory is in an electronic，or volatile state. When the computer is off，main memory is empty; when it is on，main memory is capable of receiving and holding a copy of the software instructions and data
66、 necessary for processing. Because main memory is a volatile form of storage that depends on electric power and the power can go off during processing，users often save their work frequently onto nonvolatile secondary storage devices such as diskettes or hard disks. In general，main memory is used for
67、 the following purposes:v 主存处于一种电子化的或易丢失的状态。当计算机关着的时候，主存里面是空的;当计算机开着的时候，主存就能够接收和容纳软件指令及处理所需数据的拷贝。因为主存是一种易失性的存储方式，依赖电能，而在计算机处理过程中有可能会停电，因此用户经常将他们的东西存放在不易丢失的辅助存储器里，如软盘或硬盘。通常使用主存的目的如下: 43Main memoryv （1）Storage of a copy of the main software program that controls the general operation of the computer.
68、This copy is loaded into main memory when the computer is turned on（you will find out later），and it stays there as long as the computer is on. v （2）Temporary storage of a copy of application program instructions（the specific software you are using in your business）to be retrieved by the CPU for inte
69、rpretation and execution. v （1）存放控制计算机一般操作的主软件程序的拷贝。这种拷贝在计算机打开的时候安装在主存内（你以后会弄清楚的），而且只要计算机是开着的它就一直驻留在那儿。v（2）临时存储CPU为了解释和执行而检索的应用程序指令的拷贝（如你正在使用的业务方面的专门软件）。44Main memoryv （3）Temporary storage of data that has been input from the keyboard or other input device until instructions call for the data to be
70、transferred into the CPU for processing. v （4）Temporary storage of data that has been produced as a result of processing until instructions call for the data to be used again in subsequent processing or to be transferred to an output device such as the screen，a printer，or a disk storage device. v （3
71、）临时存储刚由键盘或其他输入设备输入的数据，直至指令要求将这些数据传送至CPU进行处理为止。v （4）临时存储已加工的数据，直至指令调用这些数据再次处理，或者要求将这些数据传送给输出设备，例如屏幕、打印机或磁盘存储设备。 45Main memoryvThe banks of RAM chips（a group of chips，usually nine，arranged in a row）are sometimes on a memory expansion card，which fits inside the system cabinet and sometimes are on the m
72、ain circuit board（main board）.Many people erroneously assume that a memory chip with a capacity of 64k can hold a substantial number of characters of data;vRAM芯片的存储单元位于内存扩展卡上（一组芯片，通常是9片，安置在一排上），内存扩展卡就在系统机箱内主电路板（母板）上。许多人错误地认为具有64 k容量的内存芯片能够容纳相同数量的数据字符。 46Main memoryvhowever，in main memory it takes ei
73、ght chips to store one character. Each chip can be thought of as representing a column of 64 k electronic light switches that can be read one row at a time. The code for a character，such as the letter C，is stored in the same row across the entire bank of memory chips. The first 8 bits build the char
74、acters; the ninth chip，the parity chip，holds the parity bit，or check bit，that is used for error detection.v但是在主存内，存放一个字符要占8个芯片。每一个芯片可以被看作代表了一个64 k的光电开关的一列，每次能够读一行。一个字符如字母C的编码被存放在整个内存芯片同一行存储单元上。开始的8位组成字母;第9个芯片是奇偶校验芯片，用来保存奇偶位或校验位，用于检错。47Main memoryv A bank of 64 k RAM chips can store 64 k，or 65536（102
75、464）bytes. Therefore，each RAM chip is capable of storing a column of 65536 bitseach bit is part of the code used to represent a character. v 64 k RAM芯片存放单元能够存放64 k或65536（102464）个字节。因此，每个RAM芯片都能够存放65536位，每一位都是代表一个字符编码的一部分。 48Main memoryv 2.Main memory（RAM）for microcomputersv The amount of random acce
76、ss memory you have in your microcomputer directly affects the level of sophistication of the software you can use. Sophisticated，or powerful programs take up a lot of space in RAM. Most of todays software programs require a minimum of 640 k to run. In general，the greater your machines memory capacit
77、y，the better，because: v 2.微机的主存（RAM）v 微机的随机存取存储器的数量直接影响所用软件的复杂程度。复杂的功能强大的程序需要大量的RAM空间。如今多数软件程序的运行最低需要640 k。一般说来，内存容量越大越好，因为:49Main memoryv（1）It can receive and use much larger programs.v（2）It can hold copies of more than one program in main memory to support the sharing of the computer by more than
78、one user at a time. v（3）It can operate faster and more efficiently.v（4）It will be able to use new，sophisticated software. v（1）它能接受和使用更大的程序。v（2）它在主存中可容纳不止一个程序拷贝，以便支持多个用户同时共享计算机。v（3）它能使操作更快更有效。v（4）它能使用新的复杂的软件。 50Main memoryv（5）It can hold images for creating graphics and animation.v（6）It can work with
79、 and manipulate more data at one time. v Two types of memory are used to increase RAM beyond the 640 k limitexpanded memory and extended memory. The type used is influenced by the sophistication of the microprocessor in your machine. v（5）它能存放图像以便创作图画和动画。v（6）它能一次处理和控制更多的数据。v 为了使RAM超出640 k的限制，可以使用两种类型
80、的内存扩展内存和扩充内存。所用内存的类型受微处理器复杂程度的影响。51Main meoryv 3. Expanded memoryv As we just described，users of early microcomputer systems couldnt increase the amount of main memory directly wired into the mainboard beyond 640 k. This situation led to the development of a wide variety of new products allowing the
81、 memory to be expanded through the use of an add on memory board or card，sometimes referred to as an external memory board. This expanded memory board is simply pressed into an expansion slot on the mainboard. An expansion slot is a “plug-in” spot on the mainboard specifically meant to support add-o
82、n components. v 3.扩展内存v正如我们刚刚叙述的，早期的微机系统用户不能用直接与主板相连接的方式把主内存增加到640 k以上。这引发了对各种新产品的开发，以便通过附加内存板或卡（有时也叫作外部内存板）来扩展内存。这种扩展内存板只要简单地插入主板的扩展槽即可。扩展槽是主板上的插口，专门用于支持附加部件。 52Main meoryvThis slot connects the add-on board with the power supply for the computer and links the board with the buses for moving data a
83、nd instructions. Some switch settings in the computer may need to be adjusted to account for the increased amount of memory，because the computer wont know how much main memory it has unless you tell it. Although this process may sound complicated，it really is not; it usually takes only a screwdriver
84、 and about 10 minutes. The instructions for installing an add-on memory board come with the board.v扩展槽与带电源的附加板相连，也与传送数据和指令的总线板相连。计算机上的某些开关设置可能需要做相应的调整，以计算要增加多少内存，因为计算机并不知道内存有多少，除非你告诉它。这个过程听起来很复杂，但其实不然:通常用一把螺丝刀，大约十几分钟即可。安装附加内存板的指令随板附带。 53Main meoryv We do need to mention here that add-on boards or ca
85、rds can be inserted only in computers with open architecturethat is，computers built to allow users to open the system cabinet and make changes. Computers with closed architecture such as some Macintosh microcomputersdo not allow the user to add expansion cards. Thus you can see that a computers arch
86、itecture becomes important to the user if he or she wants to upgrade the systemnot only to increase RAM but also to add secondary storage，graphics capabilities，some communications capabilities，or to change from a monochrome display to a color screen. v 需要说明的是，添加板或添加卡只能插入开放式结构的计算机，也就是计算机的设计允许用户为改变内存而
87、打开机箱。不具有开放式结构的计算机（如某些Macintosh微机）不允许用户增添扩展卡，因此你可以看到计算机的结构对于想更新系统的用户来说很重要。更新系统不仅仅是增加内存，也可以增添辅助存储器、绘图功能及一些通信功能，还可以将单显改成彩显。54Main meoryvIf you are buying a computer system and think you might want to upgrade it at a later date，make sure you purchase a computer with open architecture.v Expanded memory i
88、s used in 8088，8086，80286，80386，80486 and other computers.v如果你准备买一台计算机并且以后有可能需要更新的话，一定要买一台具有开放式结构的计算机。v 扩展内存主要用于8088、8086、80286、80386、80486和其他计算机中。55Main meoryv 4.Extended memoryv Extended memory also refers to memory increased above 640 k. Extended memory is also composed of RAM chips that are eith
89、er plugged directly into the mainboard or are attached to a board that is plugged into an expansion slot. With extended memory，a machine can use up to 16 MB，32 MB and even more of memory. Like expanded memory，extended memory can be used only by software that recognizes ityour applications software d
90、ocumentation will specify whether the software is compatible with one or both of these types of increased memory. v 4.扩充内存v 扩充内存指的是在640 k以上增加的内存。扩充内存也是由RAM芯片构成的，这些芯片可直接插入主板，也可附在插入扩展槽内的一块板上。有了扩充内存，计算机可以用到16 MB、32MB或者更多的内存。正如扩展内存一样，只有能够辨认它的软件才能使用它，应用软件的文件会指明是否与这两种增加的内存之一或两者都兼容。 56Main meoryv 5.Cache m
91、emoryv Some computers are designed with cache memory，to increase the speed of transfer of instructions and data from secondary storage to the processor. Like RAM，cache memory is essentially a high-speed temporary storage area for program instructions and data. However，cache memory is about10 times f
92、aster than RAM. Because its storage capacity is smaller than RAMs capacity，cache memory holds only those instructions and data that the processor needs immediately.v 5.高速缓冲存储器v 有的计算机设计成带有高速缓存，这样可加快从辅助存储器到处理器之间传送指令和数据的速度。像RAM一样，高速缓存器实质上是程序指令和数据临时存放的区域。但是高速缓存器的速度要比RAM快近10倍。因为高速缓存器的存储容量比RAM的小得多，因此它只存放那
93、些处理器要立即使用的指令和数据。 57Main meoryv 6.Read-Only Memory（ROM）v How does your computer know what to do when you turn it on? How does it know to check out your hardware components（such as the keyboard or the monitor）to see that they have been connected correctly? Instructions to perform such operations，which
94、 are critical to the operation of a computer，are stored permanently on a read-only memory（ROM）chip installed by the manufacturer inside the computer. This ROM chip，also called firmware，retains instructions in a permanently accessible ，nonvolatile form. When the power in the computer is turned off，th
95、e instructions stored in ROM are not lost. v 6.只读存储器（ROM）v 打开计算机时它如何知道该干什么?它怎么知道去检查硬件（例如键盘或显示器），看看它们连接好了没有呢?计算机的生产者把完成这些关键操作的指令永久地安装在计算机内的只读存储器（ROM）芯片上。这种ROM芯片也叫作固件，它把指令以永久的可以随时读取的非易失性的形式保存下来。关闭计算机，ROM里的指令也不会丢失。 58Main meoryv Having basic instructions permanently stored in ROM is both necessary and
96、convenient. For example ，If you are using a microcomputer with diskette drives，the more instructions in ROM，the fewer diskettes you may have to handle in order to load instructions into the computer. If you could have all the program instructions you will ever need to use in ROM，you would have every
97、thing you need for processing data and information at your fingertipsalways. v 把基本的指令永久地存放在ROM里既是必要的也是十分方便的。例如，如果你正在使用带软驱的微机，ROM里的指令越多，要把指令装入计算机需要的软盘就越少。假如你能把所需要用的全部程序指令放在ROM里，那就等于把要处理的信息和数据所需要的一切都放在指尖上了总是如此。 59Main meoryv Unfortunately， until recently the process of manufacturing ROM chips and reco
98、rding data on them was more expensive than the process of producing RAM chips. As a result，manufacturers tended to record in ROM only those instructions that were crucial to the operation of the computer. In recent years improvements in the manufacturing process of ROM chips have lowered their cost
99、to the point where manufactures are beginning to include additional software instructions.v 然而不幸的是，直到现在，生产ROM芯片和把数据录入其上的工艺要比生产RAM芯片的工艺贵得多。这样，厂家倾向于只把计算机操作最关键的那些指令安装在ROM上。近几年生产ROM芯片的工艺得到了改进，降低了成本，厂家已开始将另外的一些软件指令包含在ROM芯片之中。 60Main meoryv 7.PROM，EPROM，EEPROMv Three additional kinds of nonvolatile memory
100、 are used in some computer systemsnamely，PROMs，EPROMs，and EEPROMs. PROM stands for programmable read-only memory. This type of memory functions in the same way a regular ROM component does，with one major exceptionPROM chips are custom-made for the user by the manufacturer. In other words，the user de
101、termines what data and instructions are recorded on them. The only problem with PROM chips is that，like ROM chips，once data is recorded on them，it can not be changed. v 7.PROM、EPROM、EEPROMv 另外还有三种非易失性的存储器用于一些计算机系统当中，叫作PROM、EPROM和EEPROM。PROM代表可编程序只读存储器（Programmable ReadOnly Memory）。这种存储器的作用与通常的ROM设备一
102、样。主要不同点为:PROM芯片是厂家为用户定做的，换句话说，由用户决定把什么样的数据和指令录入其上。PROM芯片如同ROM芯片一样存在一个问题，就是一旦数据录入其上，那就无法改变了。 61Main meoryv Erasable programmable read-only memory（EPROM）chips were developed as an improvement over PROM chips. EPROM functions exactly the same as PROM; however，with the help of a special device that prod
103、uces ultraviolet light，the data or instructions on an EPROM chip can be erased in approximately 15 minutes. v 可擦除可编程序只读存储器（Erasable Programmable Read-Only Memory，EPROM）芯片是在PROM芯片的基础上开发出来的新产品。EPROM跟PROM发挥的功能完全一样;然而，借助于产生紫外光的专门设备，差不多需要15分钟，EPROM芯片上的数据和指令就会擦除。 62Main meoryvThen a device generically ref
104、erred to as a PROM burner is used to reprogram the chip. To change instructions on an EPROM chip，the chip must be taken out of the machine and then put back when changes have been made. This task is one most computer users would prefer to avoid. The alternative to erasing and rerecording an EPROM ch
105、ips is to replace it with a new EPROM that features the new program code. This is a task best performed by a trained computer professional. v然后一个通常称为PROM burner的设备重新对芯片进行编程。要改变EPROM芯片上的指令，该芯片必须从计算机中取出，等改变后再装回去。这种工作是大多数计算机用户都想避免的事情。把EPROM擦净并且再录入新的程序的另一种可行的办法是用一个赋与新程序编码的新的EPROM芯片取而代之，这种工作最好由受过训练的行家里手去
106、完成。 63Main meoryv Electrically erasable programmable read-only memory（EEPROM），a later addition to the ROM family of chips，avoids the inconvenience of having to take chips out of the computer to change data and instructions. Instead，changes can be made electrically under software control. These chips
107、 are being used in point-of-sale terminals to record price-related data for products. The prices recorded on them can be easily updated as needed. The only disadvantage of EEPROM chips is that they currently cost substantially more than regular ROM chips and disk storage devices. However，experts exp
108、ect the prices to come down substantially. v 电可擦除可编程只读存储器（Electrically Erasable Programmable Read-Only Memory，EEPROM）是ROM芯片家族的最新成员，它避免了必须把芯片从计算机中拿出来不能更换数据和指令的麻烦，改为由软件控制的电子方式完成。这些芯片已开始用零售点终端，为产品录入价格数据。需要的时候，以前的价格记录可以很容易地修改。EEPROM芯片唯一的缺陷是:现在其价格要比一般的ROM芯片和磁盘存储设备高得多，但专家们期待着其价格的大幅度下降。 64Computer EnglishL
109、esson Four Input and Output Devices第四课第四课 输入输入/ /输出设备输出设备 65Input and Output DevicesvKey Wordsv keyboard n. 键盘v imitate v. 模仿，仿造v layout n. 设计，编排，布局v punctuation n. 标点，标点符号v mouse n. 鼠标v screen n. 屏，银幕v arrow n. 箭头v cursor n. 光标，指针66Input and Output Devices vKey Wordsv commands n. 命令v touch v. 触摸，使接
110、触v infrared adj.红外线的，红外线v monitor n. 监视器v squirt v. 喷出v laser n. 激光v droplets n. 小滴v scanners n. 扫描仪v eliminate v. 消除v optical adj.视力的，光学的67Input and Output Devicesv A computer is a machine that processes data into information. Unless some human being needs the information，there is no point to proce
111、ssing the data. Without data，there are nothing to process. Input and output devices provide a means for people to access a computer. In this lesson， well consider a number of input and output devices and media to you. v 计算机是把数据处理成信息的机器。除非有些人需要信息，否则就不存在处理数据。没有数据，也就没什么要处理的。输入和输出设备为人们访问计算机提供了手段。本章，我们将向
112、你介绍一些输入/输出设备和媒质。68Input and Output Devicesv 1.Keyboardsv Computer keyboards were originally designed to imitate electric typewriters so that typists could learn to use computers more easily. The demands of computer technology， however，have led to keys and keyboard layouts never before seen on a type
113、writer. While a typewriter has only about 50 keys，a computer keyboard may have 100 or more. v1键盘v 计算机键盘最初的设计目的是模仿打字机，从而使打字员更容易学会使用计算机，但是计算机技术的需要导致键和键盘布局不再像以前打字机上看到的那样，打字机仅有50个键，而计算机键盘有100个或更多键。69Input and Output DevicesvA computers keys are generally divided into four clusters: alphanumeric keys，fun
114、ction keys，cursor keys，and the numeric keypad. Alphanumeric keys include letters，numbers，and punctuation marks. They are arranged much like the keys on a typewriter. Function keys are labeled F1，F2，and so on up to F12 or F15. v计算机键盘上的键通常分为4类：字母数字键、功能键、光标键和数字键。字母数字键包括字母、数字和标点符号，它们排列得很像打字机上的键。功能键是标有F1
115、、F2等一直到F12或F15的键，70Input and Output DevicesvThey can be used for giving common commands such as “Print” or “Quit program”. The precise purpose of any function key varies from one program to another. Cursor keys are used to move the cursor around on the screen. The cursor is the little blinking symbo
116、l that indicates where things will happen next on the screen. v它们用于给出像打印或退出程序等的普通命令，每个功能键的精确定义随程序不同而不同。光标键用于在屏幕上移动光标，光标是小的闪烁符号，它在屏幕上显示将要发生事情的位置。71Input and Output DevicesvWhen you are typing，the cursor always blinks just to the right of the last character you typed. Cursor keys include the arrow key
117、s for moving up，down，left，and right，as well as the PgDn，PgUp，Home，and End keys. The numeric keypad includes the mathematical keys found on a standard calculator. v当击键时，光标一直在最后键入的字符的右边闪烁。光标键包括上移、下移、左移和右移箭头键，还包括上翻页、下翻页、开头和结尾键。数字键区包括在标准计算器上有的数字键。72Input and Output Devicesv 2.Mousev Mice are popular bec
118、ause it is easier to point than to type，and because the arrow keys dont work very well for drawing pictures or moving things on the screen. A mouse consists of a ball mounted under a plastic housing with one or more buttons on top. As you move the mouse around the tabletop，sensors inside register th
119、e rolling of the ball and move the cursor around the screen to match. v 2鼠标v 鼠标之所以流行是因为指向比击键更容易，也因为箭头键在屏幕上画图或移动不方便。鼠标有一个塑料房状的外壳，外壳下有一滚动球，外壳上面有一个或多个按钮。当在桌面上移动鼠标时，内部的传感器记录球的滚动并在屏幕上将光标移动到相应位置。 73Input and Output DevicesvThere are three basic ways of giving commands with the mouse. First，you can click t
120、he button to identify somethingperhaps to indicate which part of a drawing you want to change. Second，you can drag the mouse; that is，you can hold the button down while you move the mouse. Dragging can be used to move a drawing across the screen. The third way to give a command is to double-click th
121、e mouses button by pressing it twice within about a half second. Clicking is used to select things on the screen.v使用鼠标发送命令有三种方式:第一，可以单击按钮来标识某一位置大概指出图片的哪一部分需要修改。第二，可拖动鼠标，也就是说，当移动鼠标时可以一直按住按钮，拖动它可以在屏幕上移动图画。第三，方式是双击鼠标，即在大约半秒内连按两次按钮，单击用于在屏幕上选择某些对象。74Input and Output Devicesv The simplest pointing tool of
122、 all，of course，is the finger. In fact，touch screens are widely used in departmentstore advertising displays，information kiosks，lottery game machines，and other places where users are not expected to have much familiarity with computers. On these machines you simply touch the part of the display scree
123、n you want to select，just as you might push a vending machines button. Depending on the sensing method used by the touch screen，your finger might interrupt a network of infrared rays protected across the screens surface. This would tell the computer where you pointed.v 当然在所有的指示工具中最简单的是手指。事实上，触摸屏广泛用于
124、商场的广告显示、信息亭、抽奖游戏机和其他不需要用户非常熟悉计算机的场合。在这些机器上，只需触摸显示屏上想选择的部分，就像按售货机上的按钮一样。依靠触摸屏上使用的传感方法，手指可以干扰保护屏幕表面的红外线网络，这样就会告诉计算机你所指的位置。 75Input and Output Devicesv 3.Monitorv A monitor，or display screen，provides a convenient but temporary way to view information. The earliest computer monitors were simply converte
125、d television sets. While ordinary TVs are still used for some video games，most computer programs today demand higher-quality monitors. The quest for better monitors has taken two paths: the improvement of TV-like screens and the development of flat screens. v 3.监视器v 监视器或显示屏提供了一种方便但临时的方法来查看信息。最早的计算机监
126、视器只是电视信号。当普通电视还被用于电子游戏时，今天的大多数计算机程序已要求更高质量的监视器。追求更好的监视器有两条路径:提高类电视屏幕的质量和开发平面显示器。 76Input and Output Devicesv 4.Printersv Different kinds of computer printers use surprisingly different technologies. Some printers squirt ink，some apply heat to sensitive paper，others hammer inked ribbons，and still oth
127、ers create images with lasers. Laser printers work by reflecting a laser beam from a rapidly rotating octagonal mirror onto a light-sensitive roller. Ink-jet printers work by squirting tiny droplets of liquid ink at the paper. v 4.打印机v 不同种类的计算机打印机使用不同的技术。有的打印机使用喷墨技术，有的使用热感技术，有的使用击打色带技术，还有的使用激光产生图像。激
128、光打印机通过快速旋转的八角形镜子反射激光束到光敏滚筒上来工作。喷墨打印机通过喷出细小的墨水滴到纸上来工作。77Input and Output DevicesvDot-matrix printer features a movable print head containing a row of tiny pins. The pins push an inked ribbon against the paper，producing a matrix（or pattern）of dots. As the print head moves back and forth across the pag
129、e，the dots can form either letters or graphics.v点阵式打印机有一个可移动的装有一排小针头的打印头，针头打击色带到纸上以产生圆点的矩阵（或图案）。当打印头在纸上来回移动时，圆点可以形成字符或图片。78Input and Output DevicesvDot-matrix printer features a movable print head containing a row of tiny pins. The pins push an inked ribbon against the paper，producing a matrix（or pa
130、ttern）of dots. As the print head moves back and forth across the page，the dots can form either letters or graphics. v点阵式打印机有一个可移动的装有一排小针头的打印头，针头打击色带到纸上以产生圆点的矩阵（或图案）。当打印头在纸上来回移动时，圆点可以形成字符或图片。 79Input and Output Devicesv 5.Scanners and Reading Devicev Some devices make the input process more efficient
131、 by eliminating the manual entry of data. Instead of a person entering data using a keyboard or pointing device，these devices capture data from a source document，which is the original form of the data. When using a keyboard or printing device to enter data，the source document might be a timecard，ord
132、er blank，invoice，or any other document that contains data to be processed. v 5.扫描仪和读入设备v 有些设备因不需人工输入数据而使得输入过程更加高效。这些设备从源文件捕捉数据（源文件是数据的初始形式），这样就不需要人用键盘或定位设备输入数据。当使用键盘或定位设备输入数据时，源文件可以是工作时间记录卡、订单表、发票或其他包含待处理数据的文档。80Input and Output DevicesvDevices that capture data directly from source documents includ
133、e optical scanners，optical character recognition devices，optical mark recognition devices，bar code scanners，and magnetic-ink character recognition readers. Examples of source documents used with these devices include advertisements，brochures，photographs，inventory tags，or checks .v直接从源文件文档捕捉数据的设备有光学扫描仪、光学字符识别仪、光学标记识别仪、条码扫描仪、磁墨字符识别阅读器。这些设备使用的源文档的例子有广告、小册子、照片、库存标签和支票。 81谢谢观赏！谢谢观赏！
