计算机英语实用教程Unit 2.doc

司爱侠 张强华 宋德富 张美兰 编著 计算机英语实用教程电子教案Unit 2 Periphery Device【教学目的】 Learn about the English terms of the periphery devices of the computer, including drive, bus, inkjet printer, modem, PCI, plug & play, CD-ROM, Hard drive, vidio-card, printer, scanner, sound card, Improve the students ability to understand the long and difficult sentences in Text A and Text B. Master the key language points and grammatical structures in the text. consolidate the technical terms and important professional phrases by doing exercises. 【教学重点难点】Important technical terms: zip drive (压缩驱动器), CD-ROMs (CD光盘), DVD-ROMs (DVD光盘), analog signals (模拟信号), digital signal (数字信号), electronic filing cabinet (电子档案柜), bubble jet Abbreviation: CD-ROM, DVD-ROM, PCI, ISA, PCMCIA, CMOS, BIOS; Difficult sentences: 1. A modem modulates outgoing digital signals from a computer or other digital device to analog signals over a conventional telephone line and demodulates the incoming analog signal and converts it to a digital signal for the digital device (computer). Mo-dem = modulate + demodulate2. Peripheral Component Interconnect (PCI) is an interconnection system between a microprocessor and attached devices in which expansion slots are spaced closely for high speed operation. Review the important points of essential English1. be meant to do sth. 设计成做某事例句：Function keys are meant to perform user-defined tasks.2. have sth. done 例句一：A device for storing and/or retrieving data. Some drives (such as disk drives, zip drives, and tape drives) are typically capable of having new data written to them例句二：A standard that gives computer users the ability to plug a device into a computer and have the device recognized automatically.【教学步骤】Step OneRead and explain Text A to the students and ask the students to keep in mind the following professional terms:1) zip drive (压缩驱动器) A high-capacity floppy disk drive developed by Iomega Corporation. Zip disks are slightly larger than conventional floppy disks, and about twice as thick. They can hold 100 or 250 MB of data. Because theyre relatively inexpensive and durable, they have become a popular media for backing up hard disks and for transporting large files. 2) CD-ROM （CD光盘） Pronounced see-dee-rom. Short for Compact Disc-Read-Only Memory, a type of optical disk capable of storing large amounts of data - up to 1GB, although the most common size is 650MB (megabytes). A single CD-ROM has the storage capacity of 700 floppy disks, enough memory to store about 300,000 text pages. CD-ROMs are stamped by the vendor, and once stamped, they cannot be erased and filled with new data. To read a CD, you need a CD-ROM player. All CD-ROMs conform to a standard size and format, so you can load any type of CD-ROM into any CD-ROM player. In addition, CD-ROM players are capable of playing audio CDs, which share the same technology. CD-ROMs are particularly well-suited to information that requires large storage capacity. This includes large software applications that support color, graphics, sound, and especially video. 3) DVD-ROM（DVD光盘） A new type of read-only compact disc that can hold a minimum of 4.7GB (gigabytes), enough for a full-length movie. The DVD-ROM specification supports disks with capacities of from 4.7GB to 17GB and access rates of 600 KBps to 1.3 MBps. One of the best features of DVD-ROM drives is that they are backward-compatible with CD-ROMs. This means that DVD-ROM players can play old CD-ROMs, CD-I disks, and video CDs, as well as new DVD-ROMs. Newer DVD players can also read CD-R disks. DVD-ROMs use MPEG-2 to compress video data. 4) analogu （模拟）& digital（数字） Also spelled analogue, describes a device or system that represents changing values as continuously variable physical quantities. A typical analog device is a clock in which the hands move continuously around the face. Such a clock is capable of indicating every possible time of day. In contrast, a digital clock is capable of representing only a finite number of times (every tenth of a second, for example). In general, humans experience the world analogically. Vision, for example, is an analog experience because we perceive infinitely smooth gradations of shapes and colors. When used in reference to data storage and transmission, analog format is that in which information is transmitted by modulating a continuous transmission signal, such as amplifying a signals strength or varying its frequency to add or take away data. For example, telephones take sound vibrations and turn them into electrical vibrations of the same shape before they are transmitted over traditional telephone lines. Radio wave transmissions work in the same way. Computers, which handle data in digital form, require modems to turn signals from digital to analog before transmitting those signals over communication lines such as telephone lines that carry only analog signals. The signals are turned back into digital form (demodulated) at the receiving end so that the computer can process the data in its digital format. 5) bubble jet printer (气泡喷墨打印机)气泡喷墨打印机是由佳能所开发的一种喷墨印表技术，与一般压电式喷墨印表方式不同的是, 气泡喷墨打印机使用特殊加热装置产生墨点。A type of ink-jet printer developed by Canon. The principal difference between bubble-jet printers and other ink-jet printers is that bubble-jet printers use special heating elements to prepare the ink whereas ink-jet printers uses piezoelectric pai7i:zEui5lektrik （压电的）crystals. A type of printer that works by spraying ionized 5aiEnaizd （离子化的）ink at a sheet of paper. Magnetized plates（磁化图版） in the inks path direct the ink onto the paper in the desired shapes. Ink-jet printers are capable of producing high quality print approaching that produced by laser printers. A typical ink-jet printer provides a resolution（分辨率） of 300 dots per inch, although some newer models offer higher resolutions. Advantages and disadvantages of the ink printerIn general, the price of ink-jet printers is lower than that of laser printers. However, they are also considerably slower. Another drawback of ink-jet printers is that they require a special type of ink that is apt to smudge on（弄脏）inexpensive copier paper. Because ink-jet printers require smaller mechanical parts than laser printers, they are especially popular as portable printers. In addition, color ink-jet printers provide an inexpensive way to print full-color documents.6) scanner: handheld, hopper-feed and flatbedSome scanners are small hand-held devices that you move across the paper. These hand-held scanners are often called half-page scanners because they can only scan 2 to 5 inches at a time. Hand-held scanners are adequate for small pictures and photos, but they are difficult to use if you need to scan an entire page of text or graphics.Larger scanners include machines into which you can feed sheets of paper. These are called sheet-fed scanners. Sheet-fed scanners are excellent for loose sheets of paper, but they are unable to handle bound（装订的）documents. A second type of large scanner, called a flatbed scanner, is like a photocopy machine. It consists of a board on which you lay books, magazines, and other documents that you want to scan. Overhead scanners (also called copyboard scanners) look somewhat like overhead projectors. You place documents face-up on a scanning bed, and a small overhead tower moves across the page. 7) tape driveA device, like a tape recorder, that reads data from and writes it onto a tape. Tape drives have data capacities of anywhere from a few hundred kilobytes to several gigabytes. Their transfer speeds also vary considerably. Fast tape drives can transfer as much as 20MB (megabytes) per second. The disadvantage of tape drives is that they are sequential-access devices, which means that to read any particular block of data, you need to read all the preceding blocks. This makes them much too slow for general-purpose storage operations. However, they are the least expensive media for making backupsStep Two Help the students to analyze the following long difficult sentences: 1. A modem modulates outgoing digital signals from a computer or other digital device to analog signals over a conventional telephone line and demodulates the incoming analog signal and converts it to a digital signal for the digital device (computer). Mo-dem = modulate + demodulate这个长句解释了调制解调器的作用。Here “modulate” is a vt. And we often say “modulate sth to sth.” In this sentence “modulate outgoing digital signals from a computer or other digital device to analog signals over a conventional telephone line” means in Chinese: 通过传统的电话线把从计算机或其他数字设备传出来的信号调制成模拟信号。同样后面的demodulate为“解调”，作者为了避免表达重复，加进一个动词convert sth. to.，实际上当然也可以使用demodulate sth. to sth. .后半部分的意思是“为数字设备（计算机）把进入的模拟信号转换成数字信号”。2. Peripheral Component Interconnect (PCI) is an interconnection system between a microprocessor and attached devices in which expansion slots are spaced closely for high speed operation. 本句的难点首先是三个名词术语的汉译：(1) PCI Peripheral Component Interconnect “外围设备互连借口”(2) interconnection system 互连系统 (3) expansion slot扩充插槽；其次是定语从句中的谓语动词space的被动语态。space作为vt. 用法和意义如下：To separate or keep apart. 隔开或保持距离e.g. space out the lampposts 30 meters apart把路灯柱每根隔开三十米space out payments for a house over twenty years分20年分期付款买房子Space the interviews so that you have some time between the different candidates. 把接见申请人的时间拉开，这样在不同的申请者之间留有时间余地。本句中的spaced closely表达的意思是两层意思，一是扩充插槽应该分开，二是还要紧凑。汉语可以译成：扩展槽必须分开但排列紧凑，这样以便高速操作。Step ThreeReview the important idioms of essential Englishl be meant to do sth. 设计成做某事；必须；得要；（因能力、命运等）注定这一习惯用法来自作为vt.动词mean，这里mean的基本意思是intend（打算，想要），但到了被动态后，主语为动作的承受者，而动作得执行者经常是不明确的，科技英语中常表示主语的功能，以下例句充分说明了这种现象：Function keys are meant to perform user-defined tasks.功能键用于执行用户定义的任务。I believe he is meant to be a soldier. 我相信他天生是要当军人的。You are meant to leave a tip. 你得留下小费。l Have sth. done 这是基础英语中常见的have的用法，do的动作不是主语发出的，而是别人发出的，无须提及，最常见的有have ones hair cut（理发），have ones shoes repaired（修鞋）；当然也能表示遭遇，如have ones purse stolen（钱包让偷了），have ones leg injured（腿受伤了）等。计算机专业英语中经常能够见到have的这种用法： 1. Some drives (such as disk drives, zip drives, and tape drives) are typically capable of having new data written to them. 一些驱动器（如磁盘驱动器，压缩驱动器和磁带驱动器）一般都能够写入新的数据。2. Plug & play is a standard that gives computer users the ability to plug a device into a computer and have the device recognized automatically. 即插即用是一种标准，它使计算机用户把设备插入计算机后就立即自动得到认可。这个功能由操作系统执行。（have the device recognized automatically与动词不定式to plug a device into a compute