Editing Source Code Control System (section)

==Background==

The Source Code Control System (SCCS) is a system for controlling file and history changes. Software is typically [[Source upgrade|upgraded]] to a new version by fixing bugs, optimizing algorithms and adding extra functions.<ref>Home Organization Selection {{ProQuest|215925387}}</ref> Changing software causes problems that require version control to solve.<ref name = "r1"/>
* Source code takes up too much space because it is repeated in every version.
* It is hard to acquire information about when and where changes occurred.
* Finding the exact version which the [[Client–server model|client]] has problems with is difficult.
SCCS was built to solve these problems. SCCS from AT&T had five major versions for the IBM OS and five major versions for UNIX<ref>The evolution of a Source Code Control System. Alan L.Glasser, published in sigmetrics, Nov 1978 when SCCS on UNIX was a version 4</ref>
Two specific implementations using SCCS are: PDP 11 under Unix and IBM 370 under the OS.<ref name = "r1"/>