Concurrent Versions System

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Concurrent Versions System

Developer(s)	The CVS Team
Initial release	November 19, 1990; 33 years ago (1990-11-19)
Stable release	1.11.23[1] / May 8, 2008; 15 years ago (2008-05-08)
Preview release	1.12.13[2] / September 28, 2005; 18 years ago (2005-09-28)
Repository	savannah.nongnu.org/projects/cvs
Written in	Revision control
License	GPL-1.0-or-later[3]
Website	cvs.nongnu.org

Concurrent Versions System (CVS, or Concurrent Versioning System) is a

CVS operates as a

Released under the terms of the GNU General Public License, CVS is free software.

Design

CVS operates as a

containing a corresponding history file for each file in the repository.

CVS uses

for efficient storage of different versions of the same file. This works well with large text files with few changes from one version to the next. This is usually the case for source code files. On the other hand, when CVS is told to store a file as binary, it will keep each individual version on the server. This is typically used for non-text files such as executable images where it is difficult to create compact deltas between versions.

CVS excludes symbolic links because when they are stored in a version control system they can pose a security risk. For instance, a symbolic link to a sensitive file can be stored in the repository, making the sensitive file accessible even when it is not checked in. In place of symbolic links, scripts that require certain privileges and conscious intervention to execute may be checked into CVS.^{[citation needed]}

Operation

CVS labels a single project (set of related files) that it manages as a

the changes in the repository with the working copy.

CVS uses a

files. CVS can also run external, user-specified log processing scripts following each commit. These scripts are installed by an entry in CVS's loginfo file, which can trigger email notification or convert the log data into a Web-based format.

CVS can also maintain different "branches" of a project. For instance, a released version of the software project may form one branch, used for bug fixes, while a version under current development, with major changes and new features, can form a separate branch. CVS assumes that the majority of work takes place on the trunk, and that branches should generally be short-lived or historical. When used as designed, branches are easily managed and branch operations are efficient and fast.^[7][8]

Portability

The server software normally runs on Unix (although at least the CVSNT server also supports various flavors of Microsoft Windows), while CVS clients may run on any major operating system platform.

History

Grune recalled:^[9]

I created CVS to be able to cooperate with my students, Erik Baalbergen and Maarten Waage, on the ACK (Amsterdam Compiler Kit) C compiler. The three of us had vastly different schedules (one student was a steady 9-5 worker, the other was irregular, and I could work on the project only in the evenings). Their project ran from July 1984 to August 1985. CVS was initially called cmt, for the obvious reason that it allowed us to commit versions independently.

Grune publicly released the code on June 23, 1986.^[10]

The code that eventually evolved into the current version of CVS started with Brian Berliner in April 1989, with later input from Jeff Polk and many other contributors. Brian Berliner wrote a paper introducing his improvements to the CVS program—which describes how the tool was extended and used internally by Prisma, a third-party developer working on the SunOS kernel, and was released for the benefit of the community under the GPL.^[11] On November 19, 1990, CVS version 1.0 was submitted to the Free Software Foundation for development and distribution.^[12]

The latest version was released on 8 May 2008.^[13]

Adoption and successors

In the world of open source software, the Concurrent Version System (CVS) has long been the tool of choice for version control. And rightly so. CVS itself is free software, and its non-restrictive modus operandi and support for networked operation—which allow dozens of geographically dispersed programmers to share their work—fits the collaborative nature of the open-source world very well. CVS and its semi-chaotic development model have become cornerstones of open-source.^[14]

Over time, developers have created new version control systems based on CVS in order to add features, alter the operational model, and improve developers' productivity. CVS replacement projects include

See also

• Comparison of version-control software
• Cervisia
• OpenGrok
• StatCVS
• TortoiseCVS
• ViewVC

Notes

References

• ISBN 0-9745140-0-4
  .
• Jennifer Vesperman (2006). Essential CVS (2e ed.). O'Reilly.
  ISBN 0-596-52703-9
  .
• Per Cederqvist; et al. (2002). Version Management with CVS.
  ISBN 0-9541617-1-8. Archived from the original
  on 2014-08-05. Retrieved 2009-11-25.
• Karl Franz Fogel;
  ISBN 1-932111-81-6. Archived from the original
  on 2014-07-16. Retrieved 2002-02-05.

External links

• Official website
• Version Management with CVS: manual for CVS 1.12.13, by Per Cederqvist et al.