An approach to large program testing with tool WHEN

The problem to test large application and system programs efficiently in supercomputer systems is discussed. Many difficulties exist when large programs are concerned. In order to overcome some of these difficulties, we design a novel software tool named WHEN, which has been used to solve some dynamic internal testing problems, such as flexible flowtracing, debugging of deep rooted errors or faults, internal structural analysis of foreign programs, program testing in batch and real time systems, etc. in the supercomputer software development where large programs are often found. This paper first discusses some problems in the large program testing. Then WHEN is introduced with an efficient implementation of WHEN on supercomputers. Third, an approach to large program testing with the tool WHEN is explained with a few practical application examples. Finally, a method to improvement of software design for testability and maintainability is suggested