Unisys mainframes do (since 1980)! File versions are termed "cycles": by default new files are allocated a single cycle but that can be changed at allocation ti

Unisys mainframes do (since 1980)! File versions are termed "cycles": by default new files are allocated a single cycle but that can be changed at allocation time or later. They also had a source editor that kept versions within a file cycle. Lines marked as deleted could be optionally viewed and/or recovered.