The concept of software configuration management can be mind boggling unless you are given a tentative and informed introduction to it. If you are dumped at a computer terminal with the open source code data configuration software Subversion in front of you then you might just stare blankly. The initial prerequisite for working in software configuration management is fluency in C-plus-plus or Java and a basic working knowledge of Linux or Unix.



If those names mean nothing to you then you really need to ask for your money back from the people who supplied the IT training. Otherwise you should be able to follow the basic principals from configuration management to the use of Subversion. Configuration management literally means managing change. So if two users are trying to access the same Word doc in a local network they will usually be unable to edit the doc at the same time.

This might generally be done for security reasons as the network cannot accommodate the two sets of changes, hence a message is sent to the user exclaiming a read only version of the doc is available. Without any configuration management system there is the potential for two users to open the document, do separate work then for the last one to save to overwrite the work already done and CMS is designer to avoid the aforementioned scenarios.

The example is a very basic one and with CMS both users can check out their copy of the file, while the system keeps a record of every version saved and merges the changes to the document. The Word doc example is not where CMS is most important as the real value of CMS is in software development. If you have scores of software developers working on the same source code files then a software configuration management system is essential.

SCM systems work on the basis of a central database of all files where users can check out the files, make alterations then check them back in again. The system then checks the changes against the original files and updates them keeping an archive of every generation. There are certain features that any SCM system must possess, concurrency management, versioning and synchronisation.

Concurrent management is the feature that allows multiple users to edit the same file and merges the changes by checking the updated files against the route files in the database by running a series of algorithms. Dependent on the system configuration the SCM system will either use complex algorithms to minimise the users work by automatically merging any conflicting changes intelligently, or it will notify the user to do so manually.

Versioning is the feature that stores archive copies of every file in the database so that users can recall previous versions of a file. They also can track the history of files to establish who checked what files out and when. Synchronisation is the process of a user submitting their file to the database so that the SCM system can update the file as to other changes that have been made to that particular file.