When the Linux kernel community lost free use of BitKeeper, the proprietary distributed version-control system it had relied on, Linus Torvalds set out to build a replacement. The official Git book records that “the Linux development community (and in particular Linus Torvalds, the creator of Linux) developed their own tool based on some of the lessons they learned while using BitKeeper” in 2005.
What is striking is how fast the first version came together. Torvalds began work in early April 2005 and had a tool good enough to manage its own source code, that is, self-hosting, within a matter of days, then used git to track the Linux kernel itself shortly after. The first working code was small and rough, but it already embodied the goals the book lists: speed, a simple design, strong support for non-linear development with thousands of parallel branches, full distribution, and the ability to handle a project as large as the Linux kernel.
The Git book summarizes the outcome: “Since its birth in 2005, Git has evolved and matured to be easy to use and yet retain these initial qualities. It’s amazingly fast, it’s very efficient with large projects, and it has an incredible branching system for non-linear development.”
The speed of that initial sprint became part of git’s legend, but the deeper point is that the core data model Torvalds chose under pressure proved durable enough to underpin nearly all of modern software collaboration.