I may be showing my young age here, but before Mercurial/Git there was SVN, and before that SourceSafe and the like.<p>What did software devs at IBM in the time of thick rimmed glasses and cheesy porn moustaches use? Did they just keep a backlog of their entire code base copied and timestamped?<p>I've always been curious.
My work still uses RCS (in addition to SVN and git and probably 14 other version control programs). It's great for adding individual files like conf files. Mess something up and want to reset? Just check the file out again and overwrite the existing file.