from netbsd:

from netbsd:
Update a kludge from 4.4bsd/pmax: DECstation PROMs force the clock to
be in 1972 or 1973. If the clock is set to the actual time, the PROM
appears to reset the chip date to 1972 at each reboot.
Change the "year offset" from 22 years to 24 years (good till 1997)
until this code is replaced with something that uses the chip as a
seconds-since-beginning-of-year clock (encoded as a date, relative to
1972-01-01 00:00:00).