A case study in software maintenance metrics

The QUALMS User Group has conducted a pilot study with the CAA on a large air traffic control flight and radar processing system, in association with Software Analysis Systems. QUALMS is a general purpose software measurement tool; the X-RAY structure analysis tool of Software Analysis Systems was used to provide a QUALMS front end for the system implementation languages BAL and JOVIAL. The mapping of BAL and JOVIAL into the QUALMS flowgraph model was not a trivial task. These languages are relatively low-level and require a careful syntactic analysis to ensure that a front-end modelling tool can be applied accurately to large volumes of source code. To achieve this, the X-RAY tool was used. X-RAY performs a complete structural analysis of code and is built on a general purpose syntax analyser which is well suited to languages such as BAL and JOVIAL. An initial analysis of 110 source code modules indicates that QUALMS provides a potentially useful metrics `profile´ of the code in terms of management goals