Operating systems of the 1970s handling dates beyond the year 2000

[Mark Longridge]

After trying to get Unix v5 to understand dates beyond the year 2000 I
had to wonder if any of the older operating systems from the 1970s or
older could do this.

So, did any operating system programmers from this time period have
the foresight to use 4 digits for the year? I just checked APL/360 and
it seems that it does not.

Mark L