1、 - 1 - 外文翻译 : Software and software engineering -the software appearance and enumerates As the decade of the 1980s began, a front page story in business week magazine trumpeted the following headline:” software: the new driving force.”software had come of ageit had become a topic for management conc
2、ern. during the mid-1980s,a cover story in foreune lamented “A Growing Gap in Software,”and at the close of the decade, business week warned managers about”the Software TrapAutomate or else.”As the 1990s dawned , a feature story in Newsweek asked ”Can We Trust Our Software? ”and The wall street jour
3、nal related a major software companys travails with a front page article entitled “Creating New Software Was an Agonizing Task ” these headlines, and many others like them, were a harbinger of a new understanding of the importance of computer software - the opportunities that it offers and the dange
4、rs that it poses. Software has now surpassed hardware as the key to the success of many computer-based systems. Whether a computer is used to run a business, control a product, or enable a system , software is the factor that differentiates . The completeness and timeliness of information provided b
5、y software (and related databases) differentiate one company from its competitors. The design and “human friendliness” of a software product differentiate it from competing products with an otherwise similar function .The intelligence and function provided by embedded software often differentiate tw
6、o similar industrial or consumer products. It is software that can make the difference. During the first three decades of the computing era, the primary challenge was to develop computer hardware that reduced the cost of processing and storing data .Throughout the decade of the 1980s,advances in mic
7、roelectronics resulted in more computing power at increasingly lower cost. Today, the problem is different .The primary challenge during the 1990s is to improve the - 2 - quality ( and reduce the cost ) of computer-based solutions- solutions that are implemented with software. The power of a 1980s-e
8、ra mainframe computer is available now on a desk top. The awesome processing and storage capabilities of modern hardware represent computing potential. Software is the mechanism that enables us to harness and tap this potential. The context in which software has been developed is closely coupled to
9、almost five decades of computer system evolution. Better hardware performance, smaller size and lower cost have precipitated more sophisticated computer-based systems. Were moved form vacuum tube processors to microelectronic devices that are capable of processing 200 million connections per second
10、.In popular books on “the computer revolution,”Osborne characterized a “new industrial revolution,” Toffer called the advent of microelectronics part of “the third wave of change” in human history , and Naisbitt predicted that the transformation from an industrial society to an “information society”
11、 will have a profound impact on our lives. Feigenbaum and McCorduck suggested that information and knowledge will be the focal point for power in the twenty-first century, and Stoll argued that the “ electronic community” created by networks and software is the key to knowledge interchange throughou
12、t the world . As the 1990s began , Toffler described a “power shift” in which old power structures( governmental, educational, industrial, economic, and military) will disintegrate as computers and software lead to a “democratization of knowledge.” 20th century 60s70 age Traditional software enginee
13、ring 1980s intermediate stages Object project At the end of 1980s Software process project 1990s Component project Figure 1-1 depicts the evolution of software within the context of. computer-based system application areas. During the early years of computer system development, hardware underwent co
14、ntinual change while software was viewed by many as an afterthought. Computer 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 - 3 - batch orientati
15、on was used for most systems. Notable exceptions were interactive systems such as the early American Airlines reservation system and real-time defense-oriented systems such as SAGE. For the most part, however, hardware was dedicated to the union of, a single program that in turn was dedicated to a s
16、pecific application. Evolution of software During the early years, general-purpose hardware became commonplace. Software, on the other hand, was custom-designed for each application and had a relatively limited distribution. Product software(i.e., programs developed to be sold to one or more custome
17、rs) was in its infancy . Most software was developed and ultimately used by the same person or organization. You wrote it, you got it running , and if it failed, you fixed it. Because job mobility was low , managers could rest assured that youd be there when bugs were encountered. Because of this pe
18、rsonalized software environment, design was an implicit process performed in ones head, and action 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 , however , we mus
19、t 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 justify admiration. The second era of computer system evolution (Figure 1.1) spanned the decade from the mid-1960s to th
20、e late 1970s. Multiprogramming and multiuse systems introduced new concepts of human-machine interaction. Interactive techniques 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 sour
21、ces , thereby controlling processes and producing output in milliseconds rather than minutes . Advances in on-line storage led to the first generation of database management systems. The second era was also characterized by the use of product software and the advent of software houses. Software was developed for widespread distribution in a multidisciplinary market. Programs for mainframes and minicomputers were distributed to hundreds and sometimes
