CADES

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CADES was a software engineering repository system produced to support the development of the VME/B Operating System for the ICL New Range - subsequently 2900 - computers.

From its earliest days, VME/B was developed with the aid of CADES, which was built for the purpose using an underlying IDMS database. CADES was not merely a version control system for code modules: it was intended to manage all aspects of the software lifecycle from requirements capture through to field maintenance.

[edit] Analysis

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In this objective - certainly an extremely challenging one, especially for its time - it was only partly successful. Although the process of using CADES was enforced for the initial stages of formal development, there were a number of practical problems. Initially, VME/B development was done on S/4 computers, and the compiled code for the entire operating system loaded on a New Range computer for testing. Given the length of this part of the development cycle and the extreme commercial time pressures, large numbers of binary patches to correct errors on a "temporary" basis became not only necessary, but routine. Field releases were accompanied by a file of such "patches", with the errors (hopefully) source-cleared in subsequent releases. Latterly, the process was much improved with the entire development system moved to New Range and a quickening of the compile/build process. This culminated in a daily develop/build cycle.

A second area of problem, or more accurately limitation, was the total lack of effective integrated test monitoring. Despite extensive efforts, it never proved possible to demonstrate in a rigorous way which paths within the operating system had been exercised in testing.