User:Gyu9/sandbox

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Source Code Control System (SCCS) is an early

Subsequently, SCCS was included in AT&T's commercial System III and System V distributions. It was not licensed with 32V, the ancestor to Berkeley Unix.^[2] The SCCS command set is now part of the Single UNIX Specification.

SCCS was the dominant version control system for Unix until later

Apart from fixing some Year 2000 problems in 1999, there is no active development on the various UNIX vendor specific SCCS versions.^[6] In 2006,

static char sccsid[] = "@(#)ls.c        8.1 (Berkeley) 6/11/93";

This string contains the file name, date, and can also contain a comment. After compilation, the string can be found in binary and object files by looking for the pattern "@(#)" and can be used to determine which source code files were used during compilation. The "what" command [1] is available to automate this search for version strings.

Background

The Source Code Control System (SCCS) is a system for controlling file and history changes. Source upgrade is one of the most significant parts in modern software development. In general, software upgraded to be a new version by fixing bugs, optimizing algorithms and adding extra functions.^[8] Obviously, many famous software have lots of versions，such as Java.^[9] However, additional problems occurs associate with these changes.^[10]

• Source code takes up too much space because it repeat again and again in every version.
• Passing optimization through one version to other versions is very difficult.
• It is hard to acquire the information about when and where changes occurring.
• Finding the exact version which the client has problems with is not very easy.

Therefore, Source Code Control System, the most powerful weapon to solve these problems, appeared in developers' world. SCCS itself had a lot of changes during the past time.The SCCS has nine different major versions which are designed to help programmers control changes as a software. The differences are about facilities and design changes in terms of problem solving.^[11] Two specific successful implementations using SCCS : PDP 11 under Unix and IBM 370 under the OS.^[12]

Composition

SCCS consists of two parts: SCCS commands and SCCS files.^[13] All basic operation(e.g., create, delete,edit) can be realized by SCCS commands.^[13] SCCS files have a unique format prefix s., which could be easily controlled by SCCS commands.^[14]

SCCS Files

An SCCS file is composed by three different parts:^[15]

• Delta table
• Access and tracking flags
• Body of the Text

Delta table

In SCCS, a delta refers to a change of SCCS file. Deltas are stored in a delta table, so each SCCS file has its own record of changes.^[15]

Control and Tracking Flags in SCCS Files

Every operation of each SCCS file will be tracked by flags. Their functions are as below:^[15]

• Setting permissions of editing of every SCCS file.
• Control every release of every SCCS file.
• Permitting collaborative editing of every SCCS file.
• Mutual-referencing changes of every SCCS file.

SCCS Basic Commands

There are lots of commands that can be used in SCCS. These commands help us to finish what we want to achieve without understanding how they worked.^[16] Also, the SCCS allows us to have access to history files. Moreover, it also provide some commands which allow us edit,monitor and change the source files.^[17]

Create

The sccs create command uses the text of source file to create a new history file.For example:

$ sccs create program.c

program.c:

1.1

87 lines

The outputs are name, version and lines.

Edit

sccs edit program.c

Edit a specific file.

Get

sccs get -e program.c

1.1

87 lines

The outputs are version and lines you want to get from specific file.

Prt

sccs prt program.c

This command produces a report of changes you made.

Alternatives

UNIX SCCS versions

Most

Jörg Schilling's fork

Jörg Schilling (who requested the release of SCCS in the early days of the OpenSolaris project)^[19] maintains a fork of SCCS^[20] that is based on the OpenSolaris source code. It has received major feature enhancements but remains compatible with the original SCCS versions unless using the "new project" mode.^[21]

Heirloom project

The Heirloom Project includes a version of SCCS derived from the OpenSolaris source code^[22] and maintained between December 2006 and April 2007.^[23]

GNU conversion utility