rpw3@fortune.UUCP (05/06/84)
#N:fortune:11600093:000:1621
fortune!rpw3 May 6 04:22:00 1984
The flury of IBM 1620 stories prompted an off-line mail exchange,
where the subject drifted to IBM 1410's. (How many people know
what ^L%B000012$^N means, given that "^" is really upside down over
the the following character?) The story below seemed worth posting for
nostalgia, if nothing else.
----------------
The 1410 I worked on. I wired a speaker to the "Zero Balance" light; said
light went on whenever a compare got "equal" or a sum or difference got a
zero result. The sounds you got from it were VERY useful in knowing what was
going on in the machine. You could hear it down the hall in the operators
"break room", so you could leave the card reader or printer off until you
heard the characteristic harsh buzz of the IOCS waiting for the "off-line"
to be cleared, then come back to turn them on. (We were charged for our
maintenance contract by "on line" time by IBM, which is why the off/on hassle.)
Similarly, when one of the numerical analysts came down to see how his six
hour non-linear regression was going, you could tell him quite a bit from
the sound. The main loop of the NLE program had a distinctive "squishing"
sound. As convergence of the matrix relaxation approached, the "squishes"
got closer and closer together. In fact, when they were almost continuous,
you walked over and turned on the printer, 'cause it was about to print out
the answer!
[That should bring back some memories, eh, Peter? <ospwd@emoryu1>]
Rob Warnock
UUCP: {ihnp4,ucbvax!amd70,hpda,harpo,sri-unix,allegra}!fortune!rpw3
DDD: (415)595-8444
USPS: Fortune Systems Corp, 101 Twin Dolphin Drive, Redwood City, CA 94065gwyn@brl-vgr.ARPA (Doug Gwyn ) (05/08/84)
(We need a "dinosaurs" news group) ... and that reminds me about the use of a high-speed oscilloscope to watch your program run (works best on a single-user machine): Assuming for example 16-bit addressing, put the lowest 8 bits of the PC on a high-speed DAC, the highest 8 bits on another, and connect the analog outputs to X and Y channels. It is amazing how much information one can glean from watching this display. Does anyone remember the days when computers had switches and lights?