The History And Purpose Of Fossil

Fossil is a distributed version control system (DVCS) written beginning in 2007 by the architect of SQLite for the purpose of managing the SQLite project.

Though Fossil was originally written specifically to support SQLite, it is now also used by countless other projects. The SQLite architect (drh) is still the top committer to Fossil, but there are also many other contributors.

History

The SQLite project started out using CVS, as CVS was the most commonly used version control system in thant era (circa 2000). CVS was an amazing version control system for its day in that it allowed multiple developers to be editing the same file at the same time.

Though innovative and much loved in its time, CVS was not without problems. Among those was a lack of visibility into the project history and the lack of integrated bug tracking. To address these deficiencies, the SQLite author developed the CVSTrac wrapper for CVS beginning in 2002.

CVSTrac greatly improved the usability of CVS and was adopted by other projects. CVSTrac also inspired the design of Trac, which was a similar system that was (and is) far more widely used.

Historians can see the influence of CVSTrac on the development of SQLite. Early SQLite check-ins that happened before CVSTrac often had a check-in comment that was just a "smiley". That was not an unreasonable check-in comment, as check-in comments were scarcely seen and of questionable utility in raw CVS. CVSTrac changed that, making check-in comments more visible and more useful. The SQLite developers reacted by creating better check-in comments.

At about this same time, the [Monotone][335] system appeared. Monotone was one of the first distributed version control systems. As far as this author is aware, Monotone was the first VCS to make use of SHA1 to identify artifacts. Monotone stored its content in a SQLite database, which is what brought it to the