The BitKeeper-Git-Mercurial Saga : How a License Agreement Change Shaped the Open-Source World

Uncovering the Impact of BitMover's Business Decision on the Linux Community and the Birth of Git

The world of version control systems is an ever-evolving landscape. Among the various systems that have been developed, two that have stood out are BitKeeper and Git. While both have been instrumental in the development of open-source projects, their paths have been vastly different.

In this lesson, we will explore the history and impact of the license agreement change for BitKeeper, the version control system used by the Linux development community, and how it led to the creation of Git.

Bitkeeper

BitKeeper is a proprietary distributed version control system that was developed by BitMover, a company founded by Larry McVoy in 2000.

The BitKeeper-Linux Relationship

BitKeeper was a proprietary, distributed version control system developed by BitMover. It was widely used by the Linux development community, and the Linux kernel development team was one of the primary users of BitKeeper at the time. The Linux kernel development process involves large numbers of developers working on a large codebase with frequent releases, and BitKeeper was well-suited for this purpose.

Yeah, as you think, the linux community of open source developers werent happy about the usage of this closed source tool. Since at that time this tool was satisfactory for them. they were continued with the working.

The Change in License Agreement

In 2005, the license agreement for the free version of BitKeeper was changed, which made the toolless suitable for the Linux kernel development process. The changes included restrictions on the use of BitKeeper by open-source projects and commercial companies that compete with BitMover, the company that developed BitKeeper. The changes were made to "protect their intellectual property" and ensure a "sustainable business model".

Breaking the Boundaries: Mercurial vs BitKeeper

In 2005, Andrew Tridgell, the developer of the Samba file server and the open-source version control system Mercurial, was accused of violating the terms of service of the proprietary version control system BitKeeper. Tridgell had reverse-engineered the BitKeeper protocol in order to create Mercurial, which was a free and open-source alternative.

BitMover, the company that developed BitKeeper, claimed that Tridgell had violated the terms of service by reverse-engineering their software and creating a competing product. They also claimed that Tridgell had distributed unauthorized copies of BitKeeper.

Tridgell denied these claims, stating that he had only used publicly available information to create Mercurial and that he had not distributed any unauthorized copies of BitKeeper. He also stated that BitKeeper's license agreement allowed for reverse engineering for the purpose of interoperability with other software.

The dispute between Tridgell and BitMover led to the discontinuation of the free version of BitKeeper and the development of the Git version control system by Linus Torvalds and other members of the Linux community as a replacement for BitKeeper.

This dispute was more of a public disagreement on the use of open-source software, BitMover accused Tridgell of violating their TOS, but there isn't any evidence of him actually breaking any laws.

The Birth of Git

As a response to the change in the license agreement, Linus Torvalds and other Linux developers decided to create a new version control system, Git. Git was specifically designed to meet the needs of the Linux kernel development process. It was also designed to be fast, efficient, and able to handle large binary files. Git quickly gained popularity, and it has since become the primary version control system used by the Linux kernel development team and many other open-source projects.

Business Perspective

From a business perspective, the change in the free license agreement for BitKeeper could be seen as a good move for the company that developed it, BitMover. By limiting the use of the free version of BitKeeper to non-commercial projects, the company was able to protect its intellectual property and ensure a sustainable business model. However, it also had the consequence of alienating a large portion of the open-source community, including the Linux kernel development team, which was one of the primary users of BitKeeper at the time.

From a business perspective, it depends on the company's priorities and goals, the change in license agreement may have been a good deal for BitMover as a short-term strategy, but it also hurt the company's reputation and long-term prospects. In short, the change in the free license agreement for BitKeeper had both positive and negative consequences for the company, and it depends on the perspective you are looking at.