Section 2.2. Software Configuration Management

2.2. Software Configuration Management

SCM, the subject of Chapter 4, is the ability to keep track of different versions of the source files that are used to create software products. Even when just one person is changing these source files, it's very useful to be able to see how a file evolved over time or even to undo some changes that in hindsight you regret making. As projects grow in size and complexity, effective SCM tools become vital. To put it another way, projects that don't use an SCM tool won't grow successfully.

SCM tools also provide a good way to share your work with other people in a controlled manner. Rather than just using a common location such as a directory to exchange files with other people, with an SCM tool you can make sure that interdependent files are changed together and you can control who is allowed to make changes. SCM tools also allow you to save messages about what changed in the source files, and also why the files were changed, which can be used to work out which releases a particular bug was fixed in.

Many SCM tools provide ways to support one or more existing releases of a product, while still allowing the team to develop the next release using different versions of the same source files. For instance, after a product is released, all the source files for that release can be marked (or even branched) to allow future bug fixes for that release, while the next release is developed independently.

Chapter 4 describes all of the above in more detail and examines seven of the most commonly used or promising SCM tools: CVS, Subversion, Arch, Perforce, BitKeeper, ClearCase, and Visual SourceSafe.