论文资料-----计算机软件外文翻译资料

论文资料-----计算机软件外文翻译资料内容摘要：

se in the number of puter systems, puter software program for beginning expansion. The pany39。 s development projects designed tens of thousands of source files statement. Purchase from external software products added dozens, million of the new statement. Trouble emerged: All of these procedures all of these sources sentence if mistakes are found, they have to make corrections. If there are changes in user requirements, we will have to revise。 Or adapted to cope with the purchase of new hardware. These are generally referred to as software maintenance. Software maintenance costs in the energy, its alarm rate to the frequency of troubleshooting source. But even worse is that many of the personal characteristics of procedures they have in fact made it is impossible to maintain. This appeared software crisis. The development of puter systems from the third era began in the mid1970s until now: Distribution System more puters, with various puter operation and mutual munication greatly increased the plexity of puter systems. Global works and local area works, broadband digital munications and the growing of the instant data access request, the software developers raised very high demands. Many personal puter software panies has been the driving force for development. Despite the second era of software panies sold only a few hundred, a few thousand sets, the third era of software panies have sold tens of thousands, even hundreds of thousands of sets. Personal puter hardware will soon bee a modity, and puter software will enable the characteristics are different. In fact, in the mid1980s, when the personal puter sales growth rate tends to slow, sales of software products still continue to grow. Many people spent on household and industrial use of the software purchase money than necessary puter software more money. The fourth puter software era has just begun. Feigenbaum and McCorduck [FEI83] These authors predicted: fifthgeneration puter and related software in the world will be on political power and the balance of industrial power have a farreaching impact. The fourth generation of software development technology (4 GT) is changing the software in the Community of certain sectors of the puter program design methods. Expert systems and artificial intelligence software has been the ultimate laboratory to the people from the reality of the problems in the practical application. With the era came to the fourth, the software crisis continues to deepen. Now we can describe software crisis following ways: 1. Hardware plex procedures have been beyond our hardware design to the development potential of software capabilities. 2. The design of the new procedures failed to keep pace with the ability of the new procedural requirements. 3. Maintenance has been the ability of poor design and lack of resources threats. As a software crisis response, software engineering practice is applied to the entire industrial fields. 20 years ago, can be wise to draw up puter software is a person less than 1%. Today, the majority of professionals and the public to a large extent, many people feel they have to understand software, is it true? One stresses the software may be described textbooks Software: (1) after the operation to provide the specified functionality and performance Directive (puter program)。 (2) enables the proper procedures for handling information data structure。 (3) A description of procedures for handling and use of documents. Not to say, can give a more plete definition, but what we need is not only a formal definition. Software Features Understanding software (mainly software engineering), the first inspection software is different from other artificial material characteristics. Building hardware, the creation process (analysis, design, manufacture and testing) eventually transformed into material form. If manufacturers a new puter, the initial plan, a formal board layout design and simulation of the evolution of a prototype of VLSI chips, circuit boards and power supplies, and other material products. The software is a logical rather than physical system ponents. Therefore software and hardware have pletely different characteristics: In the past five years, the software factory concept has been discussed in the literature (for example: [MAN84], [TAJ84]. Software factory of the term does not mean that the hardware production and software development is equivalent. Note that this is a very important point. Moreover, software factory concept proposals for the development and use of automated software tools. Software does not wear. Bathtub curve that in the early life of the hardware, and its failure rate is relatively high. These failures are often processed and manufactured by design or due to the shortings. Shortings ruled out after a certain period of time, the failure rate dropped to a lower stable level. However, with the passage of time, as hardware ponents by dust, vibration, misused, temperature limits and the longterm role of many other bad environmental impact, its failure rate went up again. In short, hardware begun wear. Unlike hardware software as vulnerable to the adverse environmental impact of loss. However, in the initial operation of procedures and found no defects will trigger a higher failure rate. However, once can be corrected, if there is no other errors, will curve flattening. Obviously, the software will not wear and tear, but it does deteriorate. In use, the software will be any change (maintenance). Revised software, it may lead to some new defect, failure rate increased, in the failure rate curve back to the initial steady state failure rate before and the need for another revision, the result of the rise again. Gradually the lowest failure rate be。