View source for History of software configuration management

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{{History of computing}}

The history of [[software configuration management]] (SCM) can be traced back as early as the 1950s, when CM (configuration management), originally for hardware development and production control, was being applied to software development. Early software had a physical footprint, such as [[Punched card|cards]], [[Punched tape|tapes]], and other media. The first software configuration management was a manual operation. With the advances in language and complexity, [[software engineering]], involving configuration management and other methods, became a major concern due to issues like schedule, budget, and quality. Practical lessons, over the years, had led to the definition, and establishment, of procedures and tools. Eventually, the tools became systems to manage software changes.<ref>"1988 "A Guide to Understanding Configuration Management in Trusted Systems" National Computer Security System (via [https://books.google.com/books?id=CScMNjwwK8UC&q=configuration+management+systems Google])</ref> Industry-wide practices were offered as solutions, either in an open or proprietary manner (such as [[Revision Control System]]). With the growing use of computers, systems emerged that handled a broader scope, including [[requirements management]], design alternatives, quality control, and more; later tools followed the guidelines of organizations, such as the [[Capability Maturity Model]] of the [[Software Engineering Institute]].

==Timeline==
* Early 1960s or even late 1950s: CDC UPDATE and IBM IEB_UPDATE.<ref>{{Cite web|url=http://www.daveeaton.com/scm/CMFAQ.html|title=Obsolete: Configuration Management Frequently Asked Questions}}</ref>
* Late 1960s into 1970s: [[The Librarian (version control system)|The Librarian]] is released by [[Applied Data Research]] and provides an alternative to keeping programs on punched card decks for the [[IBM mainframe]] market.<ref>{{cite interview | url=https://conservancy.umn.edu/handle/11299/107328  | title=An Interview with Martin Goetz | first=Martin | last=Goetz | interviewer=Jeffrey R. Yost | publisher=Charles Babbage Institute, University of Minnesota | location=Washington, D.C. | date=May 3, 2002 | pages=5&ndash;7 | access-date=May 26, 2023 }}</ref>
* Late 1960s, early 1970s: Professor Leon Pressor at the [[University of California, Santa Barbara]] produced a thesis on change and configuration control.  This concept was a response to a contract he was working on with a defense contractor who made aircraft engines for the [[US Navy]].
* Early 1970s: [[Unix]] <code>[[make (software)|make]]</code>.
* By 1970 CDC update was an advanced product.
* Circa 1972: [[Bell Labs]] paper describing the original <code>[[diff]]</code> algorithm.
* 1972, with an [[IEEE]] paper in 1975: source code control system, [[Source Code Control System|SCCS]], [[Marc Rochkind]] Bell Labs. Originally programmed in [[SNOBOL]] for [[OS/360]]; subsequently rewritten in [[C (programming language)|C]] for Unix (used diff for comparing files).
* 1970s: [[Lisle, Illinois]]-based [[Pansophic Systems]] offered PANVALET, which was an early source code control system for the mainframe market.<ref>[http://purl.umn.edu/107601 Oral history interview with Joseph Piscopo], [[Charles Babbage Institute]], University of Minnesota.  Piscopo founded Pansophic Systems in 1969 and led it until his retirement in 1987.  Interview discusses the development of Panvalet and the acquisition of Easytrieve.</ref>
* 1975: Professor Pressor's work eventually grew into a commercially available product called Change and Configuration Control (CCC) which was sold by the SoftTool corporation.
* Revision Control System ([[Revision Control System|RCS]], Walter Tichy).
* Early 1980s: <code>[[Patch (Unix)|patch]]</code> (around 1985, [[Larry Wall]]).
* 1984: Aide-de-Camp
* 1986: Concurrent Version System ([[Concurrent Versions System|CVS]]).
* 2000: [[Subversion (software)|Subversion]] initiated by [[CollabNet]].
* Early 2000s (decade): [[distributed revision control]] systems like BitKeeper and [[GNU]] arch become viable.

==Background==
Until the 1980s, SCM could only be understood as ''CM'' applied to software development.<ref>{{cite book| isbn=0-333-30719-4|title=Software Configuration Management|author=J.K. Buckle|year=1982 |publisher=Macmillan }}</ref> Some basic concepts such as ''identification'' and ''baseline'' (well-defined point in the evolution of a project) were already clear, but what was at stake was a set of techniques oriented towards the ''control'' of the activity, and using formal processes, documents, request forms, control boards etc.

It is only after this date that the use of software ''tools'' applying directly to software ''artefacts'' representing the actual resources, has allowed SCM to grow as an autonomous entity (from traditional CM).

The use of different tools has actually led to very distinct emphases.

* traditional CM for Software, typically around [[change management|Change Management]] (examples: [[Continuus]], [[Concurrent Versions System|CVS]] or ClearCase UCM)
* line oriented management, based on patches or [[Change Set]]s
* focused on [[Derived Object]]s and Build Management (example: [[Rational ClearCase|Base ClearCase]]/clearmake)

==Evolution==

===First generation===

SCCS (first released in 1973) and DSEE (considered a predecessor of [[Rational ClearCase|Atria ClearCase]]), described in 1984,<ref>{{cite journal |url=https://dl.acm.org/doi/10.1145/390011.808255 |title=Computer-Aided Software Engineering in a distributed workstation environment |first1=David B. |last1=Leblang |first2=Robert P. |last2=Chase  |journal=ACM SIGPLAN Notices |volume=19 |number=5 |pages=104–112 |date=May 1984|doi=10.1145/390011.808255 |url-access=subscription }}</ref> are two other notable VCS software tools. These tools, along with [[Revision Control System]] (RCS), are generally considered the first generation of VCS as automated software tools.<ref name=":0" />

===Second generation===

After the first generation [[Version control system|VCS]], tools such as [[Concurrent Versions System|CVS]] and [[Apache Subversion|Subversion]], which feature a locally centralized repository, could be considered as the second generation VCS. Specifically, CVS (Concurrent Versions System) was developed on top of RCS structure, improving scalability of the tool for larger groups, and later PRCS,<ref>{{cite web |url=https://prcs.sourceforge.net/ |title=PRCS, the Project Revision Control System |last=MacDonald |first=Joshua P |date=2004-05-09 |accessdate=2021-10-29}}</ref> a simpler CVS-like tool which also uses RCS-like files, but improves upon the delta compression by using [[Xdelta]] instead.

By 2006 or so, Subversion was considered to be the most popular and widely in use VCS tool from this generation and filled important weaknesses of CVS.{{whom|date=May 2022}} Later SVK developed with the goal of remote contribution feature, but still the foundation of its design were similar to its predecessors.<ref name=":0" />

===Third generation===

As Internet connectivity improved and geographically distributed software development became more common, tools emerged that did not rely on a shared central project repository. These allow users to maintain independent repositories (or [[Fork (software development)|forks]]) of a project and communicate revisions via [[changeset]]s.
[[BitKeeper]], [[Git]], [[Monotone (software)|Monotone]], [[darcs]], [[Mercurial]], and [[GNU Bazaar|bzr]]
are some examples of third generation version control systems.<ref name=":0">{{Cite web|url=http://www.catb.org/~esr/writings/version-control/version-control.html|title=Understanding Version-Control Systems (DRAFT)|first=Eric|last=Raymond|website=www.catb.org|access-date=2017-02-13}}</ref>

==See also==

* {{Annotated link|Revision control}}

==References==
<references/>

[[Category:Version control systems]]
[[Category:History of software|Software configuration management]]