Designing software for maintenance and performance

An approach to addressing the performance issues in the early stages of the design of a software system is presented. The module decomposition of the trouble-analysis subsystem is considered as an example in using this approach. Each module is characterized by its hidden information, external behaviour, and a set of performance parameters. A working system is built using these modules, and it is found that the response time of the working system varies from over an hour to less than a minute by simply varying the value of the performance parameter. Consequently, the system could be tuned by simply varying the value of the performance parameter and not by restructuring the system. The values of the parameters are selected to minimize the response time. The approach is illustrated by a case study involving a pattern recognition system which isolates faults in circuit packs.<>