Microsoft Visual SourceSafe

Microsoft Visual SourceSafe (VSS) is a discontinued source control program, oriented towards small software development projects. Like most source control systems, SourceSafe creates a virtual library of computer files. While most commonly used for source code, SourceSafe can handle any type of file in its database, but older versions were shown to be unstable when used to store large amounts of non-textual data such as images, and compiled executables.

SourceSafe was originally created by a North Carolina company called One Tree Software. One Tree SourceSafe had gone through several releases in their 1.x to 2.x cycles, supporting DOS, OS/2 (with a Presentation Manager GUI), Windows, Windows NT, Mac, and Unix. When Microsoft bought OneTree in 1994, they immediately ceased development on all versions except for Windows. Microsoft SourceSafe 3.1, Windows 16-bit-only and Macintosh, rebranded One Tree 3.0 versions, were briefly available before Microsoft released a Version 4.0. With the acquisition of One Tree Software, Microsoft discontinued its source code control product at the time, Microsoft Delta. After the acquisition, Mainsoft Corporation developed SourceSafe for UNIX in cooperation with Microsoft. Later, Metrowerks, Inc. developed Visual SourceSafe for Macintosh in cooperation with Microsoft.

SourceSafe was initially not a client/server Source Code Management, but rather a local only SCM system. Architecturally, this serves as both a strength and weakness of design, depending on the environment it is used in. It allows a single user system to be set up with less configuration than that of some other SCM systems. In addition, the process of backing up can be as simple as copying all of the contents of a single directory tree. For multi-user environments, however, it lacks many important features found in other SCM products, including support for atomic commits of multiple files (CVS has the same problem as it is built upon the original RCS). SourceSafe inherits its shared functionality using direct remote file system access to all the files in the repository. This, together with historic bugs in the codebase, occasionally led to SourceSafe database corruption, a problem noted by Microsoft.