【正文】 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 began to increase, the software has been revised many times and because of the deterioration. Wear on the other hand shows that the distinction between software and hardware. When the hardware ponents wear, available spare parts to replace. The software did not spare parts. Each software fault in the design of all the mistakes in the design or translated into machine executable code in the course of the mistakes. Therefore software maintenance much more plex than the hardware maintenance. Most software is customized, rather than using the existing ponents of the assembly. Try imagine that the control of microprocessing hardware product design and manufacturing methods. Design engineers painting of a simple digital circuit draft, in order to do some basic analysis that its functions can be realized, then access digital device manual. Each integrated circuit (IC or chip) is a part number, a determined and effective function of a welldefined interface, and a standard principle of the integration group. After each good selection of ponents can be drawn. Sadly, software designers can not afford this luxury. Almost without exception, there is no soft ponents catalog. An offtheshelf software can be scheduled, but only a End as a whole, but not the new procedure can be assembled into ponents. Although the software reusability exposition number (for example, [BIG84]), but the real success of the current not more. Software Components Computer software is the existence of two basic forms: a nonmachine executable ponents, and the other is the machine executable ponents. In view of the purpose of this module discussed here can be introduced only with the machine executable instructions directly related software ponents. Software design forms translated into language, the language of the software provides data structure, attributes and related requirements of the process. The language can form into machine language translation executable instructions procedures to deal with them. If humanity through natural language (English, Spanish or Russian) and the puter is the best of the exchanges. Unfortunately, a lot of vocabulary, grammar and plex in Context (context) on the basis of prejudice to the understanding of natural language by the manmachine munication. Semantic information processing and natural language research in the field of identification (such as [WIN83]) for the plane to natural language as a medium for the exchange of laid the foundation. However, at least in the next few years, the language used to write procedures limited to the form of artificial language. All programming languages are artificial language. Each artificial languages have limited vocabulary, grammar and clear definition of the perfect syntactic and semantic rules. These attributes of machine translation is necessary. As one of the software ponents on the form of language into machinelevel language features, highlevel language and nonlanguage course. Machinelevel language is the CPU instruction set of symbols said. When a good software developers can be developed maintenance, good documentation process, the machine language can be effective use of memory and speed of implementation of optimization procedures. A design clumsy, are not even documented procedures, machines may add language to be emerging issues. Even if the machine language does provide attractive operating speed and storage characteristics, it still has many serious shortings: 1. The plexity of the language forms of information and expression of a low level of abstraction to achieve the ability to extend the time (referring to programming time)。 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