ITH
IT History Journal
February 18

Feb 18, 1977 — The First Version Control System Was Released

February 18, 1977

On February 18, 1977, the first widely distributed version of SCCS (Source Code Control System) was published as part of Version 7 Unix at Bell Labs.

This was one of the first practical tools that allowed developers to track changes in source code files.

Today, version control is everywhere. In 1977, it was a new idea.

What Was SCCS?
SCCS stands for Source Code Control System. It was created at Bell Labs by Marc J. Rochkind.

Before tools like SCCS, developers kept multiple copies of files by hand:

file.c

file_new.c

file_final.c

file_final2.c

It was easy to lose track of changes.

SCCS introduced a structured way to:

Store revision history inside a special file format

Record who changed what and when

Add comments to each change

Reconstruct any previous version of a file

This was revolutionary for team development.

How It Worked
SCCS stored history in text-based “s-files”.

Instead of saving full copies of every version, it stored deltas — the differences between revisions. That made it efficient even on machines with very limited disk space.

You could:

Check out a file

Modify it

Check it back in with a message

This sounds normal today. In 1977, it was advanced engineering.

The People Behind It
SCCS was developed at Bell Laboratories, the same research center where Unix itself was created.

Key figures of that era included:

Ken Thompson — co-creator of Unix

Dennis Ritchie — creator of C

Marc J. Rochkind — author of SCCS

SCCS became part of the Unix ecosystem and influenced many future systems.

Why It Matters
SCCS directly influenced later tools:

RCS (Revision Control System)

CVS (Concurrent Versions System)

Subversion

Git

Modern distributed version control systems are far more powerful, but the core idea — structured, incremental history — began here.

February 18, 1977 marks the moment version control became a standard engineering practice rather than a personal habit.

From that point forward, software development could scale.

And today, every git commit carries a small echo of SCCS.