Software configuration management for medium-size systems

Abstract

Software configuration management for large real systems is an ugly task. For such systems large-scale software configuration management systems are necessary. Small systems don't need software configuration management except a way to backup. This paper describes a simple software configuration management system (called SCMB) for real medium-size systems.

SCMB obtains its simplicity from clearly separating revision control (i.e.maintaining sequences) from variant control (i.e. maintaining alternatives) and instrument elimination.

Center of SCMB is the variant control system VCS. VCS maintains variants and sets of variants using a context free grammar. The terminals and nonterminals of the grammar reemerge as names of variant subsystems of the hierarchally structured system.

Based on VCS, a common revision control system for modules, and a compiler, which is able to analyze the dependency structure of modules, the SCMB is used

• •to check the variant consistency of the system.

• •to generate configurations of the system according to a triple (revision, variant, instrumentation).

• •to manage revisions of the system

This paper describes design, implementation, experiences and limitations of SCMB, which has been used for the development and maintenance of the BirliX operating system, consisting of 300 Modula-2 modules containing about 200000 lines of code.