计算机外文翻译---计算机引论.doc

introduction to computer1 .computer literacythe vocabulary of computing is all around you. before the advent of computers, memory was the mental ability to recall previous experiences; storage was an area where you kept out -of-season clothing; and communication was the act of exchanging opinions and information through writing, speaking, or signs. in todays world, these words and countless others have taken on new meanings as part of the common terminology used to describe computers and their uses.when you hear the word computer, initially you may think of those found in the workplacethe computers used to create business letters, memos, and other correspondence; calculate payroll; track inventory; or generate invoices. in the course of a day or a week, however, you encounter many other computers. your home, for instance, may contain a myriad of electronic devices, such as cordless telephones, vcrs, handheld video games cameras, and stereo systems, which include small computers.computers help you with your banking in the form of automatic teller machines (atms) used to deposit or withdraw funds. when you buy groceries, a computer tracks your purchases and calculates the amount of money you owe; and sometimes generates coupons customized to your buying patterns.even your car is equipped with computers that operate the electrical system, control the temperature, and run sophisticated antitheft devices.computers are valuable tools. as technology advances and computers extend into every facet of daily living, it is essential you gain some level of computer literacy. to be successful in todaywo4ld, you must have knowledge and understanding of computers and their uses.2. what is a computer and what does it doa computer is an electronic machine, operating under the control of instructions stored in its own memory, which can accept data (input), manipulate the data according to specified rules (process), produce results (output), and store the results for future use.data is a collection of un-organized facts, which can include words, numbers, images, and sounds. computers manipulate and process data to create information.information is data that is organized, has meaning, and is useful. examples are reports, newsletters, a receipt, a picture, an invoice, or a check. data is processed and manipulated to create a check. data entered into a computer is called input. the processed results are called output. thus, a computer processes input to create output. a computer also can hold data and information for future use in an area called storage. this cycle of input, process, output, and storage is called the information processing cycle.a person that communicates with a computer with a computer or uses the information it generates is called a user. the electric, electronic, and mechanical equipment that makes up a computer is called hardware. software is the series of instruction that tells the hardware how to perform tasks. without software, hardware is useless; hardware needs the instructions provided by software to process data into information.3.the components of a computera computer consists of a variety of hardware components that work together with software to perform calculations, organize data, and communicate with other computer.these hardware components include input devices, output devices, a system unit, storage devices, and communications devices.3.1 input devicesan input device allows a user to enter data and commands into the memory of a computer. four commonly used input devices are the keyboard, the mouse, a microphone, and a pc camera.a computer keyboard contains keys that allow you to type letters of the alphabet, number, spaces, punctuation marks, and other symbols. a computer keyboard also contains special keys that allow you to allows you to move the pointer. you also can make choices and initiate processing on the computer by using a mouse.a microphone allows you to speak to the computer in order to enter data and control the actions of the computer. a pc camera allows others to see you while communicating with you, as well as allowing you to edit videos, create a movie, and take digital photographs.3.2 output devices a printer produces text and graphics, such as photographs, on paper or other hardcopy medium. a monitor, which looks like a television screen, is used to display text and graphics. speakers allow you to hear music, voice, and other sounds generated by the computer.3.3 system unitthe system unit is a box-like case made of metal or plastic that houses the computer electronic circuitry. the circuitry in the system unit usually is part of or is connected to a circuit board called the motherboard.two main components on the motherboard are the central processing unit (cpu), also called a processor, is the electronic device that interprets and carries out the instructions that operate the computer.memory is a series of electronic elements that temporarily holds data and instructions while they are being processed by the cpu. both the processor and memory are chips. a chip is an electronic device that contains many microscopic pathways designed o carry electrical current. chips(figure1-2), which usually are no bigger than one-half inch square, are packaged so they can be connected to a motherboard or other circuit boards.some computer components, such as the processor and memory resided inside the system unit; that is, they are internal. other components, like keyboard, mouse, microphone, monitor, pc camera, and printer, are often system unit. these devices are considered external. any external device that attaches to the system unit is called a peripheral device.3.4 storage devicesstorage holds data, instructions, and information for future use. storage differs from memory, which can hold these items permanently, whereas memory holds these items only temporarily while they are being processed. a storage medium (media is the plural) is the physical material on which data, instructions, and information are stored. one commonly used storage medium is a disk, which is a round, flat piece of plastic or metal on which items can be encoded, or written.a storage device is used to record and retrieve data, instructions, and information to and from a storage medium. storage devices often function as a source of input because they transfer items from storage into memory. four common storage devices are a floppy disk drive, a hard disk drive, a cd-rom drive, and a dvd-rom drive. a disk drive is a device that reads from and writes onto a disk.a floppy disk consists of a thin, circular, flexible disk enclosed in a plastic shell. a floppy disk stores data, instructions, and information using magnetic patterns and can be inserted into and removed from a floppy disk drive. a zip disk give is a higher capacity floppy disk that can store the equivalent of about 70standard floppy disks.a hard disk provides much greater storage capacity than a floppy disk. a hard disk usually consists of several circular disks on which data, instructions, and information are stored magnetically. these disks are enclosed in an airtight, sealed case, which often is housed inside the system unit. some hard disks are removable, which means they can be inserted and removed from a hard disk drive, much like a floppy disk. removable disks are enclosed in plastic or metal cartridges so that they can be removed from the drive. the advantage of removable media such as a floppy disk and removable hard disk is it can be taken out of the computer and transporter or secured.another type of disk used to store data is the compact disc. a compact disc stores data using microscopic pits, which are created or played using a cd-rom drive, which is accessed or played using a cd-rom drive. a variation of the standard cd-rom, you can also erase and store data on a cd-rw. a newer type of compact disc is a fvd-rom, which has tremendous storage capacities enough for a full-length movie. to use a dvd-rom, you need a dvd-rom drive.3.5 communications devicescommunication devices enable computer users to communicate and to exchange items such as data, instruction, and information with another computer. communication devices transmit these items over transmission media, such as cable, telephone lines, or other means, used to establish a connection between two computers. a modem is a communication device that enables computers to communicate via telephone lines or other means. although modems are available as both external and internal devices, most are internal; that is, contained within the system unit.4. why is a computer a powerful toola computers power is derived from its capability of performing the information processing cycle operations with speed, reliability, and accuracy; its capacity to store huge amounts of data, instructions, and information; and its ability to communicate with other computers.4.1 speedinside the system unit, operation occurs through electronic circuits. when data, instructions, and information, flow along these circuits, they travel at close to the speed of light. this allows billions of operations to be carried out in a single second.4.2 reliabilitythe electronic components in modern computers are dependable because they have a low failure rate. the high reliability of components enables the computer to produce consistent results.4.3 accuracycomputers can process large amounts of data and generate error-free results, provided the data is entered correctly. if inaccurate data is entered, the resulting output will be incorrect. this computing principle known as garbage in, garbage out (gigo), points out that the accuracy of a computers output depends on the accuracy of the input.4.4 storagemany computers can store enormous amounts of data and make this data available for processing any time it is needed. using current storage devices, the data can be transferred quickly from storage to memory, processed, and then stored again for future use.4.5 communicationsmost computers today have the capability of communicating with other computers. computers with this capability can share any of the four information processing cycle operationsinput, process, output, and storagewith another computer. for example, two computers connected by a communications device such as a modem can share stored data, instructions, and information. when two or more computers are connected together via communications media and devices, they comprise a network is the internet, a worldwide collection of networks that links together millions of businesses, government installations, educational institutions, and individuals.5. computer softwaresoftware, also called a computer program or simply a program, is a series of instructions that tells the hardware of a computer what to do. for example, some instructions direct the computer to allow you to input data from the keyboard and store it in memory. other instructions cause data stored in memory to be used in calculations such as adding a series of numbers to obtain a total. some instructions compare two values stored in memory and direct the computer to perform alternativeoperations based on the results of the comparison; and some instructions direct the computer to print a report, display information on the monitor, draw a color graph on the monitor, or store information on a disk.before a computer can perform, or execute, a program, the instructions in the program must be placed, or loaded, into the memory of the computer. usually, they are loaded into memory from storage. for example, a program might be loaded from the hard disk of a computer into memory for execution.when you purchase a program, such as one that contains legal documents, you will receive one or more floppy disks, one or more cd-roms, or a single dvd-rom on which the software is stored. to use this software, you may install the software on the computers hard disk. software is the key to productive use of computers. with the correct software, a computer can become a valuable tool. software can be categorized into two types: system software and application software. the following sections describe these categories of software.计算机引论1.计算机文化计算词汇无处不在。计算机发明以前，“memory”( 记忆) 是回忆先前经历的思维能力；“storage”(存储)是保存过季服装的地方；“communication”(交流)是通过写、说或发送信号交流意见和信息的活动。当今世界，这些词汇及其他词汇已被赋予了新的的含义，用来描述计算机及其用途。 当你听到“计算机”这个词的时候，你或许会首先想到在工作场所的那些计算机这些计算机用来制作上午信件、备忘录、计算账单和跟踪库存或制作发票。然而一天活一周志忠，你会遇到许多其他的计算机。例如，你的家里也许有一些电子设备，如无绳电话，视频相机，手持视频游戏机，照相机和立体声系统，在这些设备中都配有小型的计算机。 计算机帮助你在自动柜员机上存取款。当你买东西时，计算机跟踪你的购买行为， 计算你所欠的金额，有时候还会制作适应你购买模式的赠券。 甚至你的小轿车也装有计算机，用你操纵电子设备，控制温度，并运行功能强大的防盗设备。 计算机是宝贵的工具。随着技术的进步，计算机渗入到日常生活的各个领域，因此，人们有必要获取某种程度的计算机文化素养。为了当今世界能取得成功，你必须具备一些计算机及其使用方面的知识。2. 什么是计算机，计算机能干什么计算机是一种电子机器，通过存储在其内存中的指令控制运行。计算机能够接收数据（输入），根据制定的规则处理数据（处理），产生结果（输出），并储存结果一遍将来使用。数据是未经组织的事实的集合，数据可以包括字符、数字、图形和声音。计算机管理数据，并将数据处理生成信息。信息是指经过组织的、有意义的、有用的数据。这样的实例有报表、新闻组、收据、图片、发票和支票。（数据经过处理后制作支票）。向计算机输入的数据称输入，处理的结果称输出，因此，计算机处理输入一遍产生输出。计算机能在某一个乘坐存储器的地方保存数据和信息以备后用。输入、处理、输出和存储的整个周期成为信息处理周期。与计算机交互，或使用计算机所产生的信息的人称用户。构成一台计算机的电器、电子和机械部件称硬件。软件是告知硬件如何完成任务的指令序列。如果没有软件，硬件毫无用处，硬件需要由软件提供的指令将数据处理成信息。3.计算机的硬件计算机由许多硬件构成，这些硬件与软件一起工作，以便执行计算、组织数据及与其他计算机通信的任务。硬件部件包括输入设备、输出设备、系统单元、存储设备和通信设备。3.1 输入设备输入设备让用户向计算机存储器输入数据和命令。四种常用的输入设备是键盘、鼠标、麦克风和pc相机。计算机键盘包括字母键，数字键，空格键，标点符号键和其他符号键。计算机键盘还包括在计算机上执行特殊功能的特殊键。鼠标时小的手持设备，骑上至少有一个按钮。鼠标控制这屏幕上光标的移动，还可以通过鼠标在计算机上进行操作选择和初始化处理。麦克风允许你对计算机讲话，以便输入数据和控制计算机的操作。pc相机是在你和其他人通信时，使他们能看到你，pc相机也允许你编辑视频，制作影片和拍摄数码相片。3.2 输出设备打印机在纸上或其他硬拷贝介质上打印文本和图形（如图片）。显示器看上去像电影屏幕 ，用来显示文本和图形。扬声器播放由计算机产生的音乐、语音和其他声音。3.3 系统单元系统单元是一个盒状的金属或塑料箱，内有计算机电子电路。系统单元的电路通常是母版的一部分或是连接母版的电路板。在木板上有两个主要的部件：中央处理器（cpu）和内存储器（简称“内存”）。cpu也成处理器，是翻译和执行计算机指令的电子部件。内存是一系列的电子元件，用来临时保存正在被cpu处理的数据或指令。cpu和内存都是芯片，是一种电子器件，其上有许多能运载电子流的微小通道。芯片大小不到半个平方英寸，精包装后连接到母版或其他电路板上。有些计算机不见岸如处理器和内存，长驻在系统单元内（亦即系统内部的设备），而另外有些部件，如键盘、鼠标、麦克风、显示器、pc相机和打印机，通常也作为系统单元，不过，这些设备被认为是外部的。任何连接系统单元的外部设备都称外设。3.4 存储器设备外存储器用来保存数据、指令和信息以备后用。外存储器与内存储器不同，围村能永久保存数据而内存仅临时保存正在被处理的数据。外村介质是存放数据、指令和信息的物理材料。一种常用的外存介质是磁盘，这是一种圆而扁的塑料或金属盘片，可写入编码的数据项。外存设备用以向存储介质记录或检索数据、指令和信息。外存设备因其传输数据到内存而作为输入数据源用。四种常用的外存设备分别是：软盘驱动器、硬盘驱动器、cd-rom驱动器和dvd-rom驱动器。磁盘驱动器是一种读写设备。软磁盘是一块薄而圆的软盘片，被封装在一个炉料封套内。软磁盘采用磁模式存储数据、指令和信息，并可插入软盘驱动器，或从软盘驱动器取出。zip 盘是一种高容量软盘，能存储相当于70张标准软盘的数据量。硬盘能比软盘提供更大的存储容量。硬盘通常由若干个圆形