BitKeeper is a discontinued

software Software consists of computer programs that instruct the Execution (computing), execution of a computer. Software also includes design documents and specifications. The history of software is closely tied to the development of digital comput ...

tool for distributed revision control of computer

source code In computing, source code, or simply code or source, is a plain text computer program written in a programming language. A programmer writes the human readable source code to control the behavior of a computer. Since a computer, at base, only ...

. Originally developed as

proprietary software Proprietary software is computer software, software that grants its creator, publisher, or other rightsholder or rightsholder partner a legal monopoly by modern copyright and intellectual property law to exclude the recipient from freely sharing t ...

by BitMover Inc., a privately held company based in

Los Gatos, California Los Gatos (; ; ) is an List of municipalities in California, incorporated town in Santa Clara County, California, United States. The population is 33,529 according to the 2020 United States census, 2020 census. It is located in the San Franc ...

, it was released as

open-source software Open-source software (OSS) is Software, computer software that is released under a Open-source license, license in which the copyright holder grants users the rights to use, study, change, and Software distribution, distribute the software an ...

under the Apache-2.0 license on 9 May 2016. BitKeeper is no longer being developed.

History

BitKeeper was originally developed by BitMover Inc., a privately held company from

owned by Larry McVoy, who had previously designed TeamWare.

BitKeeper and the Linux kernel

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 Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use and view the source code, design documents, or content of the product. The open source model is a decentrali ...

or free-software projects, one of which was the source code of the

Linux kernel The Linux kernel is a Free and open-source software, free and open source Unix-like kernel (operating system), kernel that is used in many computer systems worldwide. The kernel was created by Linus Torvalds in 1991 and was soon adopted as the k ...

. 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 Concurrent Versions System (CVS, or Concurrent Versioning System) is a version control system originally developed by Dick Grune in July 1986. Design CVS operates as a front end to Revision Control System (RCS), an older version control ...

GNU arch GNU arch software is a distributed revision control system that is part of the GNU Project and licensed under the GNU General Public License. It is used to keep track of the changes made to a source tree and to help programmers combine and other ...

Subversion Subversion () refers to a process by which the values and principles of a system in place are contradicted or reversed in an attempt to sabotage the established social order and its structures of Power (philosophy), power, authority, tradition, h ...

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. The decision made in 2002 to use BitKeeper for Linux kernel development was a controversial one. Some, including

GNU Project The GNU Project ( ) is a free software, mass collaboration project announced by Richard Stallman on September 27, 1983. Its goal is to give computer users freedom and control in their use of their computers and Computer hardware, computing dev ...

founder

Richard Stallman Richard Matthew Stallman ( ; born March 16, 1953), also known by his initials, rms, is an American free software movement activist and programmer. He campaigns for software to be distributed in such a manner that its users have the freedom to ...

, expressed concern about proprietary tools being used on a flagship free project. While project leader

Linus Torvalds Linus Benedict Torvalds ( , ; born 28 December 1969) is a Finnish software engineer who is the creator and lead developer of the Linux kernel. He also created the distributed version control system Git. He was honored, along with Shinya Yam ...

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's CEO Larry McVoy, who was also a Linux contributor. 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 Git () is a distributed version control system that tracks versions of files. It is often used to control source code by programmers who are developing software collaboratively. Design goals of Git include speed, data integrity, and suppor ...

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 of BitKeeper was officially July 1, 2005, and users were required to switch to the commercial version or change version control system by then. Commercial users were 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."

Move to open-source

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 Open-source licenses are software licenses that allow content to be used, modified, and shared. They facilitate free and open-source software (FOSS) development. Intellectual property (IP) laws restrict the modification and sharing of creative ...

, eventually releasing the software under the

Apache License The Apache License is a permissive free software license written by the Apache Software Foundation (ASF). It allows users to use the software for any purpose, to distribute it, to modify it, and to distribute modified versions of the software ...

version 2.

Notes

References

External links