BitKeeper

BitKeeper

Original author(s)	BitMover Inc.
Initial release	May 4, 2000 (2000-05-04)
Stable release	7.3.1ce / September 30, 2016 (2016-09-30)
Repository	github.com/bitkeeper-scm/bitkeeper
Written in	C
Operating system	AIX, FreeBSD, HP-UX, IRIX, Linux, Mac OS X, NetBSD, OpenBSD, Solaris, Windows
Type	Distributed revision control
License	Apache 2.0
Website	www.bitkeeper.org

BitKeeper is a software tool for distributed revision control of computer source code. Originally proprietary software, it was released as open-source software under the Apache 2.0 license on 9 May 2016. BitKeeper is produced by BitMover Inc., a privately held company based in Los Gatos, California and owned by its CEO, Larry McVoy, who had previously designed TeamWare.

History

BitKeeper was first mentioned as a solution to some of the growing pains that Linux was having in September 1998. Early access betas were available in May 1999 and on May 4, 2000 the first public release of BitKeeper was made available. BitMover used to provide access to the system for certain open source or free software projects, one of which was the source code of the Linux kernel. The license for the "community" version of BitKeeper had allowed for developers to use the tool at no cost for open source or free software projects, provided those developers did not participate in the development of a competing tool (such as Concurrent Versions System, GNU Arch, Subversion or ClearCase) for the duration of their usage of BitKeeper plus one year. This restriction applied regardless of whether the competing tool was free or proprietary. This version of BitKeeper also required that certain meta-information about changes be stored on computer servers operated by BitMover, an addition that made it impossible for community version users to run projects of which BitMover was unaware.

License concerns

The decision made in 2002 to use BitKeeper for Linux kernel development was a controversial one. Some, including GNU Project founder Richard Stallman, expressed concern about proprietary tools being used on a flagship free project. While project leader Linus Torvalds and other core developers adopted BitKeeper, several key developers (including Linux veteran Alan Cox) refused to do so, citing the BitMover license, and voicing concern that the project was ceding some control to a proprietary developer. To mitigate these concerns, BitMover added gateways which allowed limited interoperation between the Linux BitKeeper servers (maintained by BitMover) and developers using CVS and Subversion. Even after this addition, flamewars occasionally broke out on the Linux kernel mailing list, often involving key kernel developers and BitMover CEO Larry McVoy, who is also a Linux developer.

Pricing change

In April 2005, BitMover announced that it would stop providing a version of BitKeeper free of charge to the community, giving as the reason the efforts of Andrew Tridgell, a developer employed by OSDL on an unrelated project, to develop a client which would show the metadata (data about revisions, possibly including differences between versions) instead of only the most recent version. Being able to see metadata and compare past versions is one of the core features of all version-control systems, but was not available to anyone without a commercial BitKeeper license, significantly inconveniencing most Linux kernel developers. Although BitMover decided to provide free commercial BitKeeper licenses to some kernel developers, it refused to give or sell licenses to anyone employed by OSDL, including Linus Torvalds and Andrew Morton, placing OSDL developers in the same position as other kernel developers. The Git project was launched with the intent of becoming the Linux kernel's source code management software, and was eventually adopted by Linux developers.

End of support for the "Free Use" version was officially July 1, 2005 and users were required to switch to the commercial version or change version control system by then. Commercial users are also required not to produce any competing tools: In October 2005, McVoy contacted a customer using commercially licensed BitKeeper, demanding that an employee of the customer stop contributing to the Mercurial project, a GPL source management tool. Bryan O'Sullivan, the employee, responded, "To avoid any possible perception of conflict, I have volunteered to Larry that as long as I continue to use the commercial version of BitKeeper, I will not contribute to the development of Mercurial."

Open source license

During the release of version 7.2ce at May 9, 2016, BitKeeper announced that it is starting to move from proprietary to open-source license. The Apache License version 2 was chosen.

See also

• List of revision control software

External links

• Official website
• BitKeeper's note about the Nov 2003 security breach
• "Not quite Open Source" Article on Linux Weekly News, circa 1999, discussing features, licensing, Larry McVoy, and OSI.
• "No More Free BitKeeper" Discusses BitMover's decision to phase out the free version of BitKeeper
• Barr, Joe (2005), BitKeeper and Linux: The end of the road?, NewsForge (published April 11, 2005), archived from the original on April 17, 2005 discusses the BitKeeper fiasco from three viewpoints: Linus Torvalds, Larry McVoy, Andrew "Tridge" Tridgell (the alleged reverse-engineer who offers a short explanation of the situation)
• How Tridge reverse-engineered Bitkeeper and Torvalds knifes Tridgell, two articles describing Tridgell's 2005 linux.conf.au keynote and comparing what he did to statements by Torvalds and McVoy
• SourcePuller is the result of Tridgell's efforts
• RMS: BitKeeper bon-voyage is a happy ending - Richard Stallman on the Linux/BitKeeper fallout (formerly on NewsForge, currently on Linux.com)
• The Age Crunch time for Linus
• BitKeeper at the "Better SCM" Site - a collection of articles and essays about BitKeeper and its history.