Y2K and immortal executables

From: Allison J Parent <allisonp_at_world.std.com>
Date: Thu Oct 22 11:36:37 1998

< >Ok, howabout a Brigeport milling machine with the PDP-8E it was purchas
< >with in 1975, still running the same code.
<
< Sure, I can imagine that. But I can't imagine it will stop working
< on January 1, 2000, or that the clock couldn't be set back to 1975
< without affecting the milling.

Correction, what clock? Most control apps clocks are intervals, time
between events, maybe time of day or week for longer periods and its
rare that they even consider time of year.

Keep in mind that until sometime past 1981ish clocks were not chips that
kept time of day/year. Of ten they were a periodic interrupt that was
totalized for time and date. So if the clock was broken it was software
not hardware.

The one example where Y2K has hit a PDP-8 use was a nuke power plant
and the PDP-8 doing data logging had to print the right time date on
the page. If the time and date were wrong nothing stopped working
but the NRC would be upset with the dataing of the logs. FYI: Y2K
happens to hit every 7-8 years on PDP-8 OSs as they only use 3bits for
relative year. Bits used to be expensive!

< If the source code has existed in some form since the late 50s or
< early 60s, no programmer since its creation has tinkered with it?
< I can imagine a slightly more plausible situation in which the source
< was written in 1961, recompiled and tweaked throughout the Sixties,
< and somehow the source was lost after recompilation in the Seventies
< so only the executable remains, and that it's been running in some

This is likely the commonplace event and the machine by the 70s was
stable platform say like DG Nova, PDP-11 or other that has a lifespan
exceeding 10+ years or still being made.

Lost in some cases means it exists and somewhere on a backup that is
in a room with 10,000 tapes of other backups that no one has looked
at for 7+ years.

Heck my vax archive is over 7 years old and is more than 20 TK50s. I
don't recycle major backups as I've had tapes fail. So the deeper the
archive the less likely the loss and also harder to find a specific
item. This is only hobby use. business should do this far more often.

< It's not that I'm denying Y2K - it's that I think it's overblown,
< especially when it comes to antique computers.

Me too. Many system Y2K is a singular event or non event. The only
ones I even think about in relation to it are the PCs and maybe the
VAXen (I run VMS 5.3 to 5.5). The PDP-11s may not like the date but
most of the stuuff I do is not date centric so unless the OS breaks it
keeps cranking. The PC makes me worry as DOS/Win and internetorking
software may have bombs I don't know nor can fix myself. I've bumped the
clock and it seems to behave though.

Allison
Received on Thu Oct 22 1998 - 11:36:37 BST