A twist on blinkenlights

From: Derek Peschel <dpeschel_at_eskimo.com>
Date: Wed Oct 31 01:49:23 2001

While visiting the San Francisco area for the Computer Museum History
Center's awards dinner, I swung by Stanford to see their exhibit of old
(largely Stanford custom) computer hardware. Various groups at Stanford
had computer systems (mostly PDP-6 and -10 I believe), but the exhibit
highlights the Stanford Artificial Intelligence Lab, a.k.a. SAIL.

SAIL had a multiprocessor system containing a KA10, a KL10, and a PDP-6,
as well as two smaller computers dedicated to video control, two megawords
of memory (eight times the address space of the -10), and disk storage,
so they obviously had enough blinkenlights for anyone.

But one of the programmers added a box (looking more or less like a tiny
traffic light) to his office. Green meant "normal operation". Yellow meant
"parity error". (Failures tended to happen in clumps, so after finding one
error, the software would kill the affected job and then search for all other
errors and kill all other affected jobs.) Red meant "The OS has halted an
Exec-mode DDT is running". (Think "kernel debugger".) No lights meant
"Things are really messed up".

Not exactly high bandwidth, but still an elegant metaphor!

-- Derek
Received on Wed Oct 31 2001 - 01:49:23 GMT