Why the bother

Configuration Management is crucial to building reliable systems consistently. It encompases not only software compatiblities, but hardware, infrastructure and many other issues. This is a software book.

Software Configuration Management is crucial to building reliable software systems consistently. It encompasses source code management, tracking status, correlating changes with problem reports, recording versions of tools used to build products and many other issues important for auditing past product builds and repeatability in building past and current products. The bibleography will help you find resources for these advanced topics. This book is focused on developing for relatively smaller projects without comprehensive repeatability requirements. Here, we cover Source Code Management.

On any development project, especially one involving several people, a certain amount of confusion is inevitable. Writing solid code quickly is a matter of organizing the chaos. Configuration management in general and source code management in particular is basically for the purpose of managing (taking control of) the chaos.

The most important elements in this are

• Keeping track of the history of the evolution of the software.
• Allowing you to extract copies of the software at marked and unmarked points in time. Most likely, points in time that correspond to releases.
• Providing a branching capability so that you can stabilize a release branch while continuing the development on the main code branch.
• Providing a branching capability so that you can destabilize a branch on a special project involving substantial rework.
• Supporting the re-integration of work that was done on one branch into another branch. For example, in the interest of reducing chaos you do not want all the reintegration of a long project to occur exclusively at the end of the project. That way lies madness.

  With the advent of graphical diff/merge tools, great strides have been made here in the last few years.

There are many open source tools available that meet these criteria, Voir Other Resources. However, we will focus on CVS, since it is more widely used and understood than the others. So, we will give you just enough information to be dangerous.

Even still, there is other useful, but not as crucial, criteria in choosing one product over another:

• Does it support configuration management capabilities? Viz.,

  change management

  It can be very useful to be able to track changes related to particular bug reports and development projects.
  

  build support

  Many SCM products are integrated with certain or various build tools. These products ensure that the software build process produces results based on consistent versions of the source. It also eliminates the situation where only build meisters have the knowledge and skills to build a product. Such situations are common and not generally a "good thing."
  

  release support

  A few SCM products actually track which customers have which versions of which products. Using that information, it is possible to focus "emergency releases" on only the affected customers. Doing that is a good thing.
  

  process management

  It is useful to understand how you do what you do, especially if you are trying to meet ISO 9000 or capability maturity model requirements. It is very easy for such procedures to become enmeshed in otherwise useless bureaucratic paperwork. Some of the tools can facilitate some of this burden. Programmers prefer that.

• Is the interface integrated and consistent? You do not want to have to refer to documentation all the time. The functions and interfaces should be generally intuitive and obvious, based on simple introductory information.
• Is the functionality accessable with a GUI interface? Good GUI's can make doing things much more obvious.
• over a network Since individual workstations tend to not be backed up, you definitely want to try to centralize your repositories on systems that do get backed up.

These are "things to consider" for large scale institutional SCM implementations.