from
Jargon File (4.4.4, 14 Aug 2003)
parity errors
pl.n.
Little lapses of attention or (in more severe cases) consciousness,
usually brought on by having spent all night and most of the next day
hacking. "I need to go home and crash; I'm starting to get a lot of
parity errors." Derives from a relatively common but nearly always
correctable transient error in memory hardware. It predates RAM; in
fact, this term is reported to have already have been in use in its
jargon sense back in the 1960s when magnetic cores ruled. Parity
errors can also afflict mass storage and serial communication lines;
this is more serious because not always correctable.