Objectives: Introduction Over View of System Analysis and Design
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| 8.2.5 Causes of Errors The software aspects of systems design are different from concerns about hardware reliability. In hardware, for example, any design errors are reproduced in every copy of the item manufactured. However, application systems are often unique and design errors are not widely distributed. Of course, if you are working on a system that will be sold commercially, there is considerable concern over development and marketing of software packages that is rampant with design errors. Manufacturing errors are introduced during the actual production process. They are not a property of the design and, in fact, may not be in every item produced. Manufacturing errors may exist only in items made during a specific time period, either because of unknown problems with material quality or mistakes made by people newly assigned to a step in the process. In software systems, the equivalent of manufacturing errors is the small chance that, when disk or tape copies of programs are made for distribution, errors will be introduced. This problem seldom occurs, however, and should not be a major concern to the analyst. Hardware failures occur as equipment is used and begins to wear out. There is no equivalent in software that is, we do not find software unusable because it is worn out. The medium on which it is carried (such as magnetic tape or disk) may become worn or damaged, but the software will not. Therefore, the primary software problem is designing and developing software that will not fail. It is impossible to prove that there are no errors in a particular system. The causes of errors that interest the analyst are (1) not obtaining the right requirements, (2) not getting the requirements right, and (3) not translating the requirements in a clear and understandable manner so that programmers implement them properly. The transition from systems design to software development is an additional opportunity for introducing translation errors. These are the result of the programmer’s not properly understanding or interpreting the design specifications produced by analysts. Conversely, they also occur when analysts force programmers to translate specifications that are incomplete. In the latter case, the programmer is forced to make design decision while coding the software. When such misunderstanding exist and implementation occurs before they are detected, the result is a need for maintenance. Download 0.94 Mb. Share with your friends:
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