外文翻譯---軟件和軟件工程

1、<p><b>　　附 錄A</b></p><p>　　Software and software engineering</p><p>　　----the software appearance and enumerates</p><p>　　As the decade of the 1980s began, a froint

2、 page story in business week magazine trumpeted the following headline:” software:the new driving force.”software had come of age—it had become a topic for management concern.during the mid-1980s,a cover story in foreune

3、 lamented “A Growing Gap in Software,”and at the close of the decade,business week warned managers about”the SoftwareTrap—Automate or else.”As the 1990s dawned , a feature story in Newsweek asked ”Can We Trust Our Softwa

4、re? ”and The wall </p><p>　　The context in which software has been developed is closely coupled to almost five decades of computer system evolution. Better hardware performance,smaller size and lower cost ha

5、ve precipitated more sophisticated computer-based systems. We’ve moved form vacuum tube processors to microelectronic deviced that are capable of processing 200 million 包含uctions per second .In popular books on “the comp

6、uter revolution,”O(jiān)sborne characterized a “new industrial revolution,” Toffer called the advent of mic</p><p>　　FIGURE 1.1 Evolution of software.</p><p>　　Figure 1.1 depicts the evolution of soft

7、ware within the context of.computer-based system application areas. During the early years of computer system development, hardware underwent continual change while software was viewed by many as an afterthought. Compute

8、r programming was a "seat-of-the-pants" art for which few systematic methods existed. Software development was virtually unmanaged--until schedules slipped or costs began to escalate. During this period, a batc

9、h orientation was used for mos</p><p>　　During the early years, general-purpose hardware became commonplace. Software,on the other hand,was custom-designed for each application and had a relativelylimited di

10、stribution.Product software(i.e.,programs developed to be sold to one or more cunstomers) was in irs infancy . Most software was developed and unltimately used by the same person or organization. You wrote it, you got it

11、 running, and if it failed, you fixed it. Because job mobility was low, managers could rest assured that you’d be</p><p>　　Because of this personalized software environment, design was an implicit process pe

12、rformed in one’s head, and ation was often nonexistent. During the early years we learned much about the implementation of computer-based systems, but relatively little about computer system engineering .In fairness , ho

13、wever , we must acknowledge the many outstanding computer-based systems that were developed during this era. Some of these remain in use today and provide landmark achievements that continue to ju</p><p>　　T

14、he second era of computer system evolution (Figure 1.1) spanned the decade from the mid-1960s to the late 1970s. Multiprogramming and multiuser systems introduced new concepts of human-machine interaction. Interactive te

15、chniques opened a new world of applications and new levels of hardware and software sophistication. Real-time systems could collect, analyze, and transform data form multiple sources, thereby controlling processes and pr

16、oducing output in milliseconds rather than minutes. Advance</p><p>　　The second era was also characterized by the use of product software and the advent of "software houses." Software was developed

17、 for widespread distribution in a multidisciplinary market. Programs for mainframes and minicomputers were distributed to hundreds and sometimes thousands of users. Entrepreneurs from industry, government, and academia b

18、roke away to "develop the ultimate software package" and earn a bundle of money.</p><p>　　As the number of computer-based systems grew, libraries of computer software began to expand. In-house deve

19、lopment projects produced tens of thousands of program source statements. Software products purchased from the outside added hundreds of thousands of new statements. A dark cloud appeared on the horizon. All of these pro

20、grams--all of these source state ments-had to be corrected when faults were detected, modified as user requirements changed, or adapted to new hardware that was purchased. T</p><p>　　Worse yet, the personali

21、zed nature of many programs made them virtu ally unmaintainable. A "software crisis" loomed on the horizon.</p><p>　　The third era of computer system evolution began in the mid-1970s and continues

22、today. The distributed system--multiple computers, each performing functions concurrently and communicating with one another- greatly increased the complexity of computer-based systems. Global and local area networks, hi

23、gh-bandwidth digital communications, and increasing demands for 'instantaneous' data access put heavy demands on software developers.</p><p>　　The third era has also been characterized by the advent

24、and widespread use of microprocessors, personal computers, and powerful desk-top workstations. The microprocessor has spawned a wide array of intelligent products-from automobiles to microwave ovens, from industrial robo

25、ts to blood serum diagnostic equipment. In many cases, software technology is being integrated into products by technical staff who understand hardware but are often novices in software development.</p><p>　

26、　The personal computer has been the catalyst for the growth of many software companies. While the software companies of the second era sold hundreds or thousands of copies of their programs, the software companies of the

27、 third era sell tens and even hundreds of thousands of copies. Personal computer hardware is rapidly becoming a commodity, while software provides the differentiating characteristic. In fact, as the rate of personal comp

28、uter sales growth flattened during the mid-1980s, software-pr</p><p>　　The fourth era in computer software is just beginning. Object-oriented technologies (Chapters 8 and 12) are rapidly displacing more conv

29、entional software development approaches in many application areas. Authors such as Feigenbaum and McCorduck [FEI83] and Allman [ALL89] predict that "fifth-generation" computers, radically different computing a

30、rchitectures, and their related software will have a profound impact on the balance of political and industrial power throughout the world. Already, "four</p><p>　　As we move into the fourth era, the pr

31、oblems associated with computer software continue to intensify:</p><p>　　1.Hardware sophistication has outpaced our ability to build software to tap hardware's potential.</p><p>　　2.Our abil

32、ity to build new programs cannot keep pace with the demand for new programs.</p><p>　　3.Our ability to maintain existing programs is threatened by poor design and inadequate resources.</p><p>　　

33、In response to these problems, software engineering practices--the topic to which this book is dedicated--are being adopted throughout the industw.</p><p><b>　　軟件和軟件工程</b></p><p>　　—

34、—軟件的出現(xiàn)及列舉</p><p>　　在二十世紀(jì)八十年代的前十年開始的時候， 在商業(yè)周刊雜志里一個頭版故事大聲宣揚(yáng)以下標(biāo)題：“軟件，我們新的驅(qū)動力！”軟件帶來了一個時代——它成為了一個大家關(guān)心的主題。在八十年代中期，《財富》雜志的一個封面故事在哀嘆：“一個在發(fā)展的軟件”在這十年結(jié)束時，商業(yè)周刊雜志的經(jīng)理被警告只因為關(guān)于那句“軟件陷阱自動裝置或者其它”。在九十年代破曉之初，在紐約時代雜志上有個特寫詢問：“我們能信

35、任我們的軟件嗎?” 并且華爾街時報敘述了一家專業(yè)軟件公司通過辛苦的努力的頭版文章題為“創(chuàng)造新的軟件是苦惱的任務(wù)”這些文章和很多其它的類似的，是那種重要的電腦軟件的一種新的理解的先兆， 是新理解的作先驅(qū)，計算機(jī)軟件的重要機(jī)會， 它提供并且形成的危險。</p><p>　　軟件角色的演變在計算機(jī)系統(tǒng)發(fā)展的五十年左右的時間里，軟件緊密地配合著其發(fā)展。更好的硬件性能，更小的尺寸，更少的花費(fèi)已經(jīng)促成更好的計算機(jī)基礎(chǔ)系統(tǒng)。&

36、lt;/p><p>　　我們移動真空電子管處理器微觀電子學(xué)的設(shè)備已有能力每秒運(yùn)行二億條指令。在流行書籍上的電腦革命，有科學(xué)家描繪它為“一場新的工業(yè)革命”。有的科學(xué)家說微型電子學(xué)的發(fā)展是人類歷史上第三次巨大的變化，有的預(yù)言道一場工業(yè)革命在向信息社會發(fā)展在我們的生活中將有一個意義深遠(yuǎn)的效果，有的說道電腦控制的信息和知識將成為21世紀(jì)的焦點(diǎn)力量，有的提出“電子社區(qū)”將被網(wǎng)絡(luò)工作創(chuàng)造以及軟件是世界上相互交換知識的鑰匙。<

37、;/p><p>　　在九十年代初，有的科學(xué)家描述到一個力量變速器在舊的建筑（go-vern-ment的、教育的、工業(yè)的、經(jīng)濟(jì)的、軍用的）將一體化作為計算機(jī)或者軟件導(dǎo)致的知識的民主化。</p><p>　　圖1.1 軟件的演變</p><p>　　圖1.1 描述的是在計算機(jī)為主的系統(tǒng)應(yīng)用區(qū)域之內(nèi)軟件的演變的時間表。 在早年計算機(jī)系統(tǒng)發(fā)展期間，硬件進(jìn)行了連續(xù)變動。計算機(jī)編程

38、是少量系統(tǒng)的方法存在的藝術(shù)。軟件開發(fā)實(shí)際上是不被關(guān)注的—— 直到日程表滑倒了或費(fèi)用開始升級。在這個期間，批取向被多數(shù)系統(tǒng)使用了。也有例外的，著名的例外是交互式系統(tǒng)譬如早期的美國航空保留系統(tǒng)和實(shí)時針對防御系統(tǒng)。甚至在很大程度上，硬件是執(zhí)行一個專用執(zhí)行文件程序的專用物件。在早年期間， 通用硬件變得普遍。軟件，另一方面，是按客戶要求設(shè)計的為各種應(yīng)用和有相對的有限的發(fā)行。軟件產(chǎn)品(i.e.，節(jié)目顯現(xiàn)出被賣對一個或更多學(xué)生) 是在聯(lián)邦稅務(wù)局初期。

39、多數(shù)軟件由同樣人或組織開發(fā)了和最終使用。由于工作流動性是降低，如果遇到問題負(fù)責(zé)人也能放心。由于這是個人性化的軟件環(huán)境，設(shè)計是在一個人的頭腦里執(zhí)行，并且文獻(xiàn)經(jīng)常是不存在的。在早年人們學(xué)會了關(guān)于計算機(jī)為主的系統(tǒng)的實(shí)施，但較少學(xué)習(xí)關(guān)于計算機(jī)系統(tǒng)工程。但是，人們必須承認(rèn)被開發(fā)在這個時代期間的計算機(jī)為主的系統(tǒng)是有許多卓著之處的。這些令人傾慕的成就有很多保留在今天的使用中提供繼續(xù)糾錯。</p><p>　　第二個時代計算機(jī)系

40、統(tǒng)演變(圖1.1) 跨過了十年即從60 年代中期對70 年代晚期。多元化的程序和多用戶系統(tǒng)介紹了人與機(jī)器互相作用的新概念。交互式技術(shù)打開了應(yīng)用硬件和軟件優(yōu)雅新水平的一個新世界。實(shí)時系統(tǒng)能收集、分析，并且變換數(shù)據(jù)表多個來源，因此控制過程和生產(chǎn)產(chǎn)品在毫秒而不是分鐘。其優(yōu)點(diǎn)在網(wǎng)上存貯導(dǎo)致了數(shù)據(jù)庫管理系統(tǒng)的第一代。第二個時代為軟件公司出現(xiàn)并且描繪產(chǎn)品軟件的用途。軟件為普遍發(fā)行在一個多重學(xué)科的市場上這個目的而被開發(fā)了。軟件為計算機(jī)主機(jī)和微型計算機(jī)

41、吸引了上百和甚至數(shù)以萬計的用戶。從此，企業(yè)家從產(chǎn)業(yè)、go-vern-ment以及學(xué)術(shù)界打破了“開發(fā)最后軟件包”和贏得捆綁金錢的模式。 如同計算機(jī)為主的系統(tǒng)的數(shù)量在增長一樣，計算機(jī)軟件圖書館開始擴(kuò)展。機(jī)構(gòu)內(nèi)部的發(fā)展項目導(dǎo)致了成千上萬個程序源語句。被購買的軟件產(chǎn)品從外面增加了成千上萬個的新聲明。但是猶如一朵黑暗的云彩出現(xiàn)在天際，所有這些程序——所有這些有一些應(yīng)用是產(chǎn)生的缺點(diǎn)來源狀態(tài)被查出了被改，當(dāng)用戶要求修改則改變，或適應(yīng)被購買的新硬件。這

42、些活動集體叫做軟件維護(hù)。在軟件維護(hù)上工作人員花費(fèi)了很多的功夫，但是軟件還是以驚人的比率吸收資源得到資源</p><p>　　計算機(jī)系統(tǒng)演變第三個時代開始在70 年代中期直到今天。 分配系統(tǒng)—— 多臺計算機(jī)聯(lián)合工作并且執(zhí)行通信，很大地增加了計算機(jī)為主的系統(tǒng)復(fù)雜。全球性和地區(qū)網(wǎng)絡(luò)，高帶寬數(shù)字通信，已經(jīng)在軟件開發(fā)商那里對瞬間數(shù)據(jù)存取的增長的需求投入了重大需求。第三個時代為對微處理器的出現(xiàn)和以及其普遍用途，個人計算機(jī)，以

43、及強(qiáng)有力的小規(guī)模工作站。微處理器產(chǎn)生了大多智能產(chǎn)品，比如從汽車到微波爐，從產(chǎn)業(yè)機(jī)器人到血液清液診斷設(shè)備。在許多情況下， 軟件技術(shù)是聯(lián)合了解硬件的產(chǎn)品的技術(shù)職員開發(fā)的，但經(jīng)常是新手在開發(fā)軟件。個人計算機(jī)是許多軟件公司成長的催化劑。如果說第二個時代被賣的是上百或數(shù)以萬計的軟件公司他們的程序的拷貝，第三時代出售就是成千上萬個的拷貝的軟件公司。當(dāng)軟件提供區(qū)分的特征的時候，個人計算機(jī)硬件迅速地成為商品。實(shí)際上，作為個人計算機(jī)銷售成長率被鋪平在80

44、 年代中期期間，軟件產(chǎn)品銷售還在繼續(xù)增長。許多人在產(chǎn)業(yè)和在軟件上做購買軟件花費(fèi)的金錢比他們買的在家運(yùn)行的計算機(jī)更多。</p><p>　　第四個時代對計算機(jī)軟件來說是正義起點(diǎn)。面向?qū)ο蟮募夹g(shù)在許多應(yīng)用范圍迅速地偏移更加常規(guī)的軟件開發(fā)方法。作者譬如[ FEI83 ] 以及Allman [ ALL89 ] 預(yù)言"五世代" 計算機(jī)，計算的程序根本不同，并且他們的相關(guān)軟件在世界各地將對政治和工業(yè)力量的

45、平衡方面產(chǎn)生深刻的沖擊。現(xiàn)在，“軟件開發(fā)的第四代”技術(shù)改變方式軟件社區(qū)修造了計算機(jī)程序的一些段。最后，專家系統(tǒng)和人工智能軟件從實(shí)驗室進(jìn)入了現(xiàn)實(shí)世界中的廣泛問題，成為其實(shí)際應(yīng)用的軟件。人工神經(jīng)網(wǎng)絡(luò)軟件開辟了扣人心弦的類似人類信息處理能力。</p><p>　　如同我們進(jìn)入第四個時代的時候，計算機(jī)軟件的問題繼續(xù)增強(qiáng):</p><p>　　1、很多性能優(yōu)越的硬件已經(jīng)超過了我們建立軟件控制硬件的潛