(推薦)《計算機專業(yè)英語》教程.ppt

1、Computer English,Chapter 1 The History and Future of Computers,計算機專業(yè)英語,1-2,Key points: useful terms and definitions of computersDifficult points: describing the features of computers of each generation,計算機專業(yè)英語,1-3,Requirements:,1. The trends of computer hardware and software,2. Basic characteristics

2、 of modern computers,3. Major characteristics of the four generations of modern computers,4. 了解科技英語的特點，掌握科技英語翻譯要點,計算機專業(yè)英語,1-4,New Words it weighed 30 tons and contained over 18,000 vacuum tubes. 也許早期最具影響力的類似計算機的裝置應該是電子數(shù)字積分計算機，或簡稱ENIAC。它是由賓夕凡尼亞大學的J. Presper Eckert 和John Mauchly 研制的。該工程于1943年開始，并于1946

3、年完成。這臺機器極其龐大，重達30噸，而且包含18,000多個真空管。,1.1 The Invention of the Computer,計算機專業(yè)英語,1-8,1.1.1 The ENIAC The ENIAC was a major advancement for its time. It was the first general-purpose, electronic computing machine and was capable of performing thousands of operations per second. It was controlled, howeve

4、r, by switches and plugs that had to be manually set. Thus, although it was a general-purpose electronic device, it did not have a stored program. Therefore, it did not have all the characteristics of a computer . ENIAC是當時重要的成就。它是第一臺通用型電子計算機器，并能夠執(zhí)行每秒數(shù)千次運算。然而,它是由開關和繼電器控制的，必須手工設定。 因此，雖然它是一個通用型電子裝置，但是它

5、沒有儲存程序。 因此,它不具備計算機的所有特征。,1.1 The Invention of the Computer,計算機專業(yè)英語,1-9,1.1.1 The ENIAC While working on the ENIAC, Eckert and Mauchly were joined by a brilliant mathematician, John von Neuman. Together, they developed the idea of a stored program computer. This machine, called the Electronic Discret

6、e Variable Automatic Computer, or EDVAC, was the first machine whose design included all the characteristics of a computer. It was not completed, however, until 1951. 在ENIAC的研制中，一個天才的數(shù)學家Von Neuman(馮.諾伊曼)加入到 Eckert和Mauchly團隊,他們一起提出了儲存程序計算機的主意。這部機器被稱做電子離散變量自動計算機, 或簡稱EDVAC,是第一部包括了計算機所有特征的機器。然而,直到1951年，

7、它一直沒有完成。,1.1 The Invention of the Computer,計算機專業(yè)英語,1-10,1.1.1 The ENIAC Before the EDVAC was finished, several other machines were built that incorporated elements of the EDVAC design of Eckert, Mauchly, and von Neuman. One was the Electronic Delay Storage Automatic Computer, or EDSAC, which was dev

8、eloped in Cambridge, England. It first operated in May of 1949 and is probably the worlds first electronic stored-program, general-purpose computer to become operational. The first computer to operate in the United States was the Binary Automatic Computer, or BINAC, which became operational in Augus

9、t of 1949. 在EDVAC完成之前，其他一些機器建成了，它們吸收了Eckert、Mauchly和Neuman設計的要素。其中一部是在英國劍橋研制的電子延遲存儲自動計算機,或簡稱EDSAC，它在1949年5月首次運行，它可能是世界的第一臺電子儲存程序、通用型計算機投入運行。在美國運行的第一部計算機是二進制自動計算機,或簡稱BINAC,它在1949年8月投入運行。,1.1 The Invention of the Computer,計算機專業(yè)英語,1-11,1.1 The Invention of the Computer,1.1.2 The UNIVAC I Like other com

10、puting pioneers before them, Eckert and Mauchly formed a company in 1947 to develop a commercial computer. The company was called the Eckert-Mauchly Computer Corporation. Their objective was to design and build the Universal Automatic Computer or UNIVAC. Because of difficulties of getting financial

11、support, they had to sell the company to Remington Rand in 1950. Eckert and Mauchly continued to work on the UNIVAC at Remington Rand and completed it in 1951. Known as the UNIVAC I, this machine was the first commercially available computer. 像他們之前的其他計算機先驅(qū)一樣,Eckert和Mauchly在1947年組成了一家公司開發(fā)商業(yè)計算機。公司名叫Ec

12、kert-Mauchly計算機公司。他們的目標是設計并建造通用自動計算機或UNIVAC。因為難以獲得財政支持，他們不得不在1950年把公司賣給了Remington Rand公司。Eckert 和Mauchly繼續(xù)在Remington Rand公司從事UNIVAC的研制工作，并在1951年取得成功。眾所周知的UNIVAC I機器是世界上第一部商業(yè)化計算機。,計算機專業(yè)英語,1-12,1.1 The Invention of the Computer,1.1.2 The UNIVAC I The first UNIVAC I was delivered to the Census Bureau a

13、nd used for the 1950 census. The second UNIVAC I was used to predict that Dwight Eisenhower would win the 1952 presidential election, less than an hour after the polls closed. The UNIVAC I began the modern of computer use. 第一臺UNIVAC I被交付人口普查局用于1950年的人口普查。在投票點關閉后1小時之內(nèi)，第二臺UNIVAC I 被用于預測D.艾森豪威爾會贏得1952年

14、總統(tǒng)大選。UNIVAC I開始了現(xiàn)代計算機的應用。,計算機專業(yè)英語,1-13,New Words result in a continuation of the trends begun in the second generation. These trends include reduced size, reduced cost, increased speed, and reduced need for air conditioning. 作為第三代計算機標志的技術發(fā)展是在計算機中使用集成電路或簡稱IC。一個集成電路就是包含許多晶體管的一個硅片(芯片)。一個集成電路代替了計算機中的許多晶

15、體管，導致了始于第二代的一些趨勢的繼續(xù)。這些趨勢包括計算機體積減小、成本降低、速度提高和對空調(diào)的需要減少。,計算機專業(yè)英語,1-22,1.2 Computer Generations,1.2.3 Third-Generation Computers: 19641970 Although integrated circuits were invented in 1958, the first computers to make extensive use of them were not available until 1964. In that year, IBM introduced a l

16、ine of mainframe computers called the System/360. The computers in this line became the most widely used third-generation machines. There were many models in the System/360 line, ranging from small, relatively slow, and inexpensive ones, to large, very fast, and costly models. All models, however, w

17、ere compatible so that programs written for one model could be used on another. This feature of compatibility across many computers in a line was adopted by other manufacturers of third-generation computers. 雖然集成電路發(fā)明于1958年,但是直到1964年才出現(xiàn)了第一臺廣泛使用IC的計算機。那一年，IBM推出了稱為System/360的大型計算機系列。這一系列的計算機成為使用最廣泛的第三代

18、計算機。在System/360系列中有許多機型, 從小型的、相對較慢的且價格低廉的機型，到大型的、非?？斓那覂r格昂貴的機型。然而,所有的機型都是兼容的，以便在一個機型上編寫的程序可以用于另一個機型。這個在許多計算機系列間兼容的特征被其他第三代計算機制造商所采用。,計算機專業(yè)英語,1-23,1.2.3 Third-Generation Computers: 19641970 The third computer generation was also the time when minicomputers became widespread. The most popular model was

19、 the PDP-8, manufactured by DEC. Other companies, including Data General Corporation and Hewlett-Packard Company, introduced minicomputers during the third generation. 計算機的第三代也是小型計算機普及的時代。最流行的小型機是由DEC制造的PDP-8。其他公司,包括數(shù)據(jù)通用公司和惠普(Hewlett-Packard)公司,在第三代期間開發(fā)了小型計算機。,1.2 Computer Generations,計算機專業(yè)英語,1-24,1

20、.2.3 Third-Generation Computers: 19641970 The principal software development during the third computer generation was the increased sophistication of operating systems. Although simple operating systems were developed for first-and second-generation computers, many of the features of modern operatin

21、g systems first appeared during the third generation. These include multiprogramming, virtual memory, and time-sharing. The first operating systems were mainly batch systems, but during the third generation, interactive systems, especially on minicomputers, became common. The BASIC programming langu

22、age was designed in 1964 and became popular during the third computer generation because of its interactive nature. 在第三代計算機期間，軟件的主要發(fā)展是操作系統(tǒng)的復雜化程度提高。雖然為第一代和第二代計算機開發(fā)了簡單的操作系統(tǒng),許多現(xiàn)代操作系統(tǒng)的特征首先在第三代期間出現(xiàn)。這些特征包括多道程序設計、虛擬存儲和分時技術。第一代操作系統(tǒng)主要是批處理系統(tǒng),但是在第三代期間，交互式系統(tǒng)開始普及，尤其是在小型計算機上。BASIC語言發(fā)明于1964年，并由于其交互式特征而在第三代計算機期間大為流

23、行。,1.2 Computer Generations,計算機專業(yè)英語,1-25,1.2.4 Fourth-Generation Computers: 1971? The fourth generation of computers is more difficult to define than the other three generations. This generation is characterized by more and more transistors being contained on a silicon chip. First there was Large Sc

24、ale Integration (LSI), with hundreds and thousands of transistors per chip, then came Very Large Scale Integration (VLSI), with tens of thousands and hundreds of thousands of transistors. The trend continues today. 第四代計算機比其他三代更難以定義。這一代計算機的特征是一個芯片上包含越來越多的晶體管。首先，出現(xiàn)了一個芯片上具有數(shù)百和數(shù)千個晶體管的大規(guī)模集成電路(LSI)，接著出現(xiàn)了一

25、個芯片上具有數(shù)萬和數(shù)十萬個晶體管的超大規(guī)模集成電路(VLSI)。這個趨勢在今天仍在持續(xù)。,1.2 Computer Generations,計算機專業(yè)英語,1-26,1.2.4 Fourth-Generation Computers: 1971? Although not everyone agrees that there is a fourth computer generation, those that do feel that it began in 1971, when IBM introduced its successors to the System/360 line of

26、computers. These mainframe computers were called the System/370, and current-model IBM computers, although not called System/370s, evolved directly from these computers. 雖然并不是每個人都同意存在一個第四代,那些認為存在的覺得它開始于1971年，其時IBM開發(fā)了System/360系列計算機的下一系列產(chǎn)品。這些大型計算機稱為System/370,當前的IBM計算機雖然不叫做System/370，但都是從這些計算機直接發(fā)展而來的

27、。 Minicomputers also proliferated during the fourth computer generation. The most popular lines were the DEC PDP-11 models and the DEC VAX, both of which are available in various models today. 小型計算機也在第四代期間迅速增長。最流行的系列是DEC公司的PDP-11機和DEC的VAX機,二者在今天的各種機型中仍然有效。,1.2 Computer Generations,計算機專業(yè)英語,1-27,1.2 C

28、omputer Generations,1.2.4 Fourth-Generation Computers: 1971? Supercomputers first became prominent in the fourth generation. Although many companies, including IBM and CDC, developed high-speed computers for scientific work, it was not until Cray Research, Inc., introduced the Cray 1 in 1975 that su

29、percomputers became significant. Today, supercomputers are an important computer classification. 超級計算機首先在第四代中突起。雖然包括IBM和CDC(控制數(shù)據(jù)公司)在內(nèi)的許多公司都為科學工作開發(fā)了高速計算機,但是直到1975年Cray研究有限公司推出了Cray 1，超級計算機才變得有意義。今天，超級計算機是重要的計算機分類。,計算機專業(yè)英語,1-28,1.2 Computer Generations,1.2.4 Fourth-Generation Computers: 1971? Perhaps

30、the most important trend that began in the fourth generation is the proliferation of microcomputers. As more and more transistors were put on silicon chips, it eventually became possible to put an entire computer processor, called a microprocessor, on a chip. The first computer to use microprocessor

31、s became available in the mid-1970s. The first microcomputer designed for personal use was the Altair, which was sold in 1975. The first Apple computer, marketed with the IBM PC in 1981. Today, microcomputers far outnumber all other types of computers combined. 也許在第四代計算機開始的最重要趨勢是微型計算機的增長。隨著越來越多的晶體管被

32、集成到硅芯片上,將一整個計算機處理器（稱為微處理器）放在一個芯片上終于成為可能。使用微處理器的第一部計算機出現(xiàn)于1970年代。第一部專為個人使用設計的微型計算機是Altair,它于1975進入市場。第一部蘋果計算機在1981年與IBM個人計算機一起在市場上銷售。今天，微型計算機數(shù)目遠遠超過其他所有類型計算機的總和。,計算機專業(yè)英語,1-29,1.2 Computer Generations,1.2.4 Fourth-Generation Computers: 1971? Software development during the fourth computer generation sta

33、rted off with little change from the third generation. Operating systems were gradually improved, and new languages were designed. Database software became widely used during this time. The most important trend, however, resulted from the microcomputer revolution. Packaged software became widely ava

34、ilable for microcomputers so that today most software is purchased, not developed from scratch. 在計算機的第四代期間，軟件的發(fā)展開始與第三代有所不同。操作系統(tǒng)在逐漸地改進，而新的語言被發(fā)明。期間數(shù)據(jù)庫軟件被廣泛使用。然而，最重要的趨勢起因于微型計算機革命。用于微型計算機的軟件包隨處可得，因此今天大多數(shù)的軟件可以購得,而不需從頭開始開發(fā)。,計算機專業(yè)英語,1-30,1.2.5 Generationless Computers We may have defined our last generatio

35、n of computers and begun the era of generationless computers. Even though computer manufacturers talk of “fifth” and “sixth”-generation computers, this talk is more a marketing play than a reflection of reality. 我們可能已經(jīng)定義了我們最新一代計算機而且開始了計算機的無代時代。即使計算機制造商談到“第五”和“第六”代計算機,這些說法更多是市場行為，而不是真實的反映。 Advocates

36、of the concept of generationless computers say that even though technological innovations are coming in rapid succession, no single innovation is, or will be, significant enough to characterize another generation of computers. 無代計算機的觀念提倡者說，即使科技革新接二連三地迅速出現(xiàn),沒有一種革新是,或?qū)⑹亲銐蛑匾鳛榱硪淮嬎銠C的特征。,1.2 Computer Ge

37、nerations,計算機專業(yè)英語,1-31,New Words = GigaByte,吉字節(jié) flops n. 每秒浮點運算次數(shù)(floating-point operation per second),1.3 Near-future Supercomputer Directions,計算機專業(yè)英語,1-32,Some idea of what might be happening in the near future in supercomputer design can be gleaned from a press release issued by the US Department

38、 of Energy (DoE). It came out of the SUPERCOMPUTING 2002 Conference held last November in Baltimore, MD. The press release announced that the DoE had awarded IBM a $290 (USD) million contract to build the two fastest supercomputers in the world with a combined peak speed of 460 TFlops. To get an ide

39、a of the speed computing throughput 460 teraflops represents, the press release states that, “These two systems will have more than one-and-a-half times the combined processing power of all 500 machines on the recently announced TOP 500 List of Supercomputers.” 從美國能源部發(fā)行的通告中，可以收集一些有關在不久的將來超級計算機設計中可能發(fā)

40、生的事情的概念。它來自在馬里蘭州巴爾的摩市召開的2002年超級計算會議。該通告稱能源部已給IBM撥款2.9億美元建造世界上最快的兩部超級計算機，其最高綜合速度為每秒460兆兆次。為了理解每秒460兆兆次速度的含義，通告解釋說,“這兩個系統(tǒng)將會具有最近發(fā)布的500強超級計算機的總處理能力的1.5倍還多?！?1.3 Near-future Supercomputer Directions,計算機專業(yè)英語,1-33,The first system, “ASCI Purple,” apparently the DoE likes colorful names will be the worlds f

41、irst supercomputer capable of 100 Tflops. ASCI Purple will have a massive cluster of POWER-based IBM eServer systems and IBM storage systems. This supercomputer represents a fifth-generation system under the Advanced Simulation and Computing Initiative (ASCI) Program. It will serve as the primary su

42、percomputer for DoE. 第一個系統(tǒng)“ASCI Purple”,顯然能源部；生動的名字將會是世界的第一部能夠運算每秒100兆兆次的超級計算機。ASCI Purple將具有基于POWER系列的IBM eServer 系統(tǒng)和 IBM 存儲系統(tǒng)的宏大組群。這臺超級計算機代表模擬和計算行動計劃(ASCI)支持的第五代系統(tǒng)。它將作為能源部主要的超級計算機。,1.3 Near-future Supercomputer Directions,計算機專業(yè)英語,1-34,1.3 Near-future Supercomputer Directions,According to the press

43、 release, the second system will be a research machine called Blue Gene/L. It will employ advanced IBM semiconductor and system technologies based on new architectures being developed by DoE and IBM. Blue Gene/L is expected to achieve a peak performance of 360 TFlops with 130,000 processors running

44、under the Linux operating system. It will have the capability to process data at a rate of one terabit per second, equivalent to the data transmitted by ten thousand weather satellites. Applications are expected to include the simulation of very complex physical phenomena in areas such as turbulence

45、, biology and high explosives. 根據(jù)通告，第二個系統(tǒng)將會是一部被稱為Blue Gene/L的研究機器，它將使用基于新結構的先進的IBM半導體和系統(tǒng)技術,該新結構是能源部和IBM共同開發(fā)的。Blue Gene/L具有13萬臺處理器，在Linux操作系統(tǒng)下運行，可望達到每秒360兆兆次的性能。它將具有以每秒1兆兆位的速度處理數(shù)據(jù)的能力,等同于一萬個氣象衛(wèi)星傳輸?shù)臄?shù)據(jù)。其應用預期包括對非常復雜現(xiàn)象的模擬，如湍流、生物學和高空爆炸。,計算機專業(yè)英語,1-35,1.3 Near-future Supercomputer Directions,The ASCI Purple

46、system will use IBMs next generation microprocessor, the POWER5, employing a total of 12,544 of them. These 12,544 processors will be spread among 196 individual computers. The total memory bandwidth will be 156,000 GBs, the equivalent of simultaneously playing 31,200 DVD movies. A super-fast data h

47、ighway with a total interconnect bandwidth of 12,500 GB will interconnect the 196 computers. The IBM AIXL operating system will be used to run this configuration. The operating system will contain 50 terabytes of memory, an amount that is 400,000 times the capacity of the average desktop PC. There w

48、ill also be two petabytes of disk storage or holding the content of approximately one billion books. ASCI Purple系統(tǒng)將使用IBM的下一代微處理器POWER5,總數(shù)為12,544個。這12,544個處理器將分布在196部單獨的計算機之中。總內(nèi)存帶寬將是15.6GB,等同于同時地播放 31,200部DVD電影。一條具有12,500 GB帶寬的超快速數(shù)據(jù)通道將會把196臺計算機互相連接。IBM AIXL 操作系統(tǒng)將用于運行一個配置。該操作系統(tǒng)將包50兆兆字節(jié)內(nèi)存，容量是平均桌面?zhèn)€人計算機的

49、40萬倍。還將有2千兆兆字節(jié)的磁盤存儲，或可容納大約十億本書的內(nèi)容。,計算機專業(yè)英語,1-36,1.3 Near-future Supercomputer Directions,Finally, since the UNIVAC-1s introduction, raw computer speed has increased by about 11 to 12 orders of magnitude in about 50 years, or a factor of 10 every five years. This is a truly remarkable achievement. It

50、s also interesting to contemplate that, if this growth continues over the next 50 years, then by the 100th anniversary of the UNIVAC-1, computers will be operating at speeds on the order of 1023 Flops! 最后, 自從UNIVAC-1的發(fā)明以來,計算機的原始速度在50年內(nèi)增加了11至12個數(shù)量級，或每五年增加10倍。這是一個真正顯著的成就。設想一下也很有趣,如果在未來50年間仍以這樣的速度持續(xù)增長,

51、到UNIVAC-1誕生的100周年，計算機將會以大約每秒1023次的浮點運算速度運行!,計算機專業(yè)英語,1-37,一、復雜長句多 科技文章要求敘述準確，推理謹嚴，因此一句話里包含三四個甚至五六個分句的，并非少見。譯成漢語時，必須按照漢語習慣破成適當數(shù)目的分句，才能條理清楚，避免洋腔洋調(diào)。這種復雜長句居科技英語難點之首，要學會運用語法分析方法來加以解剖，以便以短代長，化難為易。例如： Factories will not buy machines unless they believe that the machine will produce goods that they are able

52、to sell to consumers at a price that will cover all cost. 這是由一個主句和四個從句組成的復雜長句，只有進行必要的語法分析，才能正確理解和翻譯。現(xiàn)試譯如下： 除非相信那些機器造出的產(chǎn)品賣給消費者的價格足夠支付所有成本，否則廠家是不會買那些機器的。 節(jié)譯：要不相信那些機器造出的產(chǎn)品售價夠本，廠家是不會買的。 后一句只用了24個字，比前句40個字節(jié)約用字40%，而對原句的基本內(nèi)容無損?？梢?，只要吃透原文的結構和內(nèi)涵，翻譯時再在漢語上反復推敲提煉，復雜的英語長句，也是容易駕馭的。,科技英語的特點,計算機專業(yè)英語,1-38,科技英語的特點,二、被

53、動語態(tài)多 英語使用被動語態(tài)大大多于漢語，如莎士比亞傳世名劇羅密歐與朱麗葉中的一句就兩次用了被動語態(tài)： Juliet was torn between desire to keep Romeo near her and fear for his life, should his presence be detected. 朱麗葉精神上受到折磨，既渴望和羅密歐形影不離，又擔心羅密歐萬一讓人發(fā)現(xiàn)，難免有性命之憂。 科技英語更是如此，有三分之一以上用被動語態(tài)。例如： (a) No work can be done without energy. 譯文：沒有能量決不能做功。 (b) All busine

54、ss decisions must now be made in the light of the market. 譯文：所有企業(yè)現(xiàn)在必須根據(jù)市場來作出決策。,計算機專業(yè)英語,1-39,科技英語的特點,三、非謂語動詞多 英語每個簡單句中，只能用一個謂語動詞，如果讀到幾個動作，就必須選出主要動作當謂語，而將其余動作用非謂語動詞形式，才能符合英語語法要求。 非謂語動詞有三種：動名詞、分詞（包括現(xiàn)在分詞和過去分詞）和不定式。例如： 要成為一個名符其實的內(nèi)行，需要學到老。 這句中，有“成為”、“需要”和“學”三個表示動作的詞，譯成英語后為： To be a true professional requ

55、ires lifelong learning. 可以看出，選好“需要”（require）作為謂語，其余兩個動作：“成為”用不定式形式 to be，而“學”用動名詞形式learning，這樣才能符合英語語法要求。,計算機專業(yè)英語,1-40,科技英語的特點,四、詞性轉(zhuǎn)換多 英語單詞有不少是多性詞，即既是名詞，又可用作動詞、形容詞、介詞或副詞，字形無殊，功能各異，含義也各不相同，如不仔細觀察，必致謬誤。例如, light 名詞： (啟發(fā))in (the)light of由于，根據(jù)； (光)high light(s) 強光，精華；(燈)safety light 安全指示燈 形容詞：(輕)light i

56、ndustry 輕工業(yè)； (明亮)light room 明亮的房間； (淡)light blue 淡藍色； (薄)light coating 薄涂層 動詞： （點燃）light up the lamp 點燈 副詞： （輕快）travel light 輕裝旅行 （容易）light come, light go 來得容易去得快 諸如此類的詞性轉(zhuǎn)換，在科技英語中屢見不鮮，幾乎每個技術名詞都可轉(zhuǎn)換為同義的形容詞。詞性轉(zhuǎn)換增加了英語的靈活性和表現(xiàn)力，讀者必須從上下文判明用詞在句中是何種詞性，而且含義如何，才能對全句得到正確無誤的理解。,Computer English,Chapter 2 Organiz

57、ation of Computers,計算機專業(yè)英語,1-42,Key points: useful terms and organization of computersDifficult points: describing the organization of computers,計算機專業(yè)英語,1-43,Requirements:,1. Terms of computer hardware,2. Organization of computers and their functions,3. 掌握專業(yè)詞匯的構成規(guī)律，特別是常用詞綴及復合詞的構成,計算機專業(yè)英語,1-44,New Wo

58、rds memory inputs this address from the address bus and use it to access the proper memory location. Each I/O devices, such as a keyboard, monitor, or disk drive, has a unique address as well. When accessing an I/O device, the CPU places the address of the device on the address bus. Each device can

59、read the address off of the bus and determine whether it is the device being accessed by the CPU. Unlike the other buses, the address bus always receives data from the CPU; the CPU never reads the address bus.,圖2-1所示的系統(tǒng)包括三組總線。最上面的是地址總線。當CPU從存儲器讀取數(shù)據(jù)或指令，或?qū)憯?shù)據(jù)到存儲器時，它必須指明將要訪問的存儲器單元地址。CPU將地址輸出到地址總線上，而存儲器從地址總線上讀取地址，并且用它來訪問正確的存儲單元。每個I/O設備，比如鍵盤、顯示器或者磁盤，同樣都有一個唯一的地址。當訪問某個I/O設備時，CPU將此設備的地址放到地址總線上。每一個設備均從總線上讀取地址并且判斷自己是否就是CPU正要訪問的設備。與其他總線不同，地址總線總是從CPU上接收信息，而CPU從不讀取地址總線。,2.1.1 System Buses,計算機專業(yè)英語,1-49,Data is transferred via the data bus. When the CPU fetches data from memory, it first