Design patterns are way older than 20 years... hell, the design pattern bible was published 22 years ago, which means design patterns were in wide circulation well before I could tie shoes. According to wikipedia CVS has been around for 26 years.
Not to mention SCCS for 44 years, and RCS for 34.
To the earlier parent who mentioned process isolation: You're thinking too much about the consumer/desktop world. The entire enterprise world was used to it and demanded it, be it on (hey, humor here) SCO UNIX (yes, they really did make a useful product before they turned evil), SunOS, VAX/VMS, MVS, BSD UNIX, etc.
The desktop world was far behind the state of the art in commercial systems in those days. Even in the 80s, you were quite possibly running your enterprise with an Oracle database, on fully memory-protected hardware. Heck - you may have even been running some of your stuff in a VM on an IBM mainframe. We took some big jumps backwards in pursuit of making computers cost-effective enough for mass adoption, and it took a while before the consumer side of things jumped forward to become the same platforms used for enterprise use.
Kids these days. ;)