🚀 go-pugleaf

I learned this one while working at the Courant Institute of Mathematical
Sciences, New York University:

Courant had vast sums of money from the Atomic Energy Commission (later
ERDA, then DOE).  They ran a major computer installation which featured
one of the first CDC 6600's; in fact, serial number 3.  Many wonderful things
were done on this machine, and many to it.  Ever hear of the supercritical
wing?

Well, the CDC had a bad habit of crashing at 3:00 or so weekdays.  It was
fairly regular about this; every few weeks, at 3:00, it would crash.  The
repairman would come in, find one of the "cordwood" PC cards burnt out,
replace it, and things would be back to normal for a while.  But everyone
worried about the mystery of the regular crash.

Turns out that, because the machine was number 3, the backplane had been
hand wire-wrapped.  The technicians had left fingerprints all over the place.
A fungus was growing on the backplane, apparently fed by the oils in the
fingerprints.  Most of the time, the air in the room was very dry, and the
fungus didn't grow.  But when the operators came in on weekdays, the moisture
in their breath was enough for the fungus to grow a bit.  Eventually it would
short a couple of pins (remember, the 6600's circuitry was run at the ragged
edge) causing something to burn out.  Of course, that bit of fungus would
get incinerated too.

An application of spray fungicide cured the problem.

---------------------

This machine is the subject of a bazillion stories, as are some of the people
around it.  It's the machine that Ken Kesey and the merry pranksters threatened
to blow up (hence, despite programming on it for a year, I never saw it;
the floor it was on was locked up).  Jacob Schwartz, my old boss, was famous
for inventing the first way to save one register when you couldn't touch the
rest: a long series of test and branch instructions (the Courant 6600 didn't
have an exchange jump instruction; that came later).  Garabedian and Jameson
did the first numerical simulations of the supercritical wing on it; that idea
later resulted in 30% fuel savings for jet engines.  Charles Peskin used it to
simulate blood flow in a dog's heart.  I used UT LISP on it; the only LISP with
CONS, CAR, CDR, and CSR (cooser); addresses were 18 bits, words were 60 bits,
so they put another pointer in a CONS cell.

Mark