RCS https://en.wikipedia.org/wiki/Revision_Control_System then SSCS https://en.wikipedia.org/wiki/Source_Code_Control_System before 1972 I'm not sure..

I assumed this history was meticulously reconstructed with a lot of hard work, but apparently Unix was one of the first systems maintained in SCCS.

I guess the part from before SCCS was still meticulously reconstructed?

Poking around a bit in the repo, I think the history prior to SCCS is just release snapshots. e.g. there is no history for the cat command in the PDP-7 Unix : https://github.com/dspinellis/unix-history-repo/commits/Rese...

iirc, Linux used to live inside of BitKeeper which was a paid for solution. I believe Linus wrote git as a replacement because he got fed up with the commercial licensing (even though they gave free copies to linux devs).

Edit: this doesn't actually answer your question of where unix used to live, rather than linux though....

> I believe Linus wrote git as a replacement because he got fed up with the commercial licensing (even though they gave free copies to linux devs).

No - BitKeeper revoked the free license because some guy (unrelated to Linux) wrote a client that reverse engineered more features than BitKeeper liked.

And Linux actually used BitKeeper only between 2002 and 2005; prior to that time, it did not use a source control system at all.

The BitKeeper reverse engineering is a fun story to read: https://lwn.net/Articles/132938/ (and short!)

The funny thing is the "reverse engineering" involved telnetting into the server and typing "help".

And if I recall correctly it sent back SCCS-style data

They did use a system---tarballs and patches---but it was just a socially constructed system rather than rigorously enforced using software. Linus has often said he would have rather gone back to that system rather than use CVS or SVN.

Fortunately instead he created Git. I'm a fan of Git, though I'm aware many aren't.

The "some guy" was Samba/rsync developer Andrew Tridgell.