Even those before git - what they're describing sounds a bit like RCS, the precursor to CVS, which came before SVN.
I've never used RCS or CVS myself, but I remember the file locking thing in descriptions of it, and that it was why CVS was named "concurrent" - it fixed that limitation.
I've never used RCS or CVS myself, but I remember the file locking thing in descriptions of it, and that it was why CVS was named "concurrent" - it fixed that limitation.