Path: utzoo!mnetor!uunet!husc6!rutgers!mtunx!lzaz!lznv!jlw
From: jlw@lznv.ATT.COM (j.l.wood)
Newsgroups: comp.arch
Subject: Re: Curb feelers (was: Cray architecture)
Message-ID: <1373@lznv.ATT.COM>
Date: 2 May 88 14:51:01 GMT
References: <7762@alice.UUCP> <418@ole.UUCP> <3216@phri.UUCP> <1574@osiris.UUCP> <621@garth.UUCP>
Distribution: na
Organization: AT&T ISL Middletown NJ USA
Lines: 24

In article <621@garth.UUCP>, walter@garth.UUCP (Walter Bays) writes:
> I liked the UNIVAC 1108.  Its console had a light that indicated CPU busy.
> Normally, the light would flicker.  If the machine was idle the light was
> off.  If it was very busy the light was on continuously.  I thought of,
> but never tried, using a photo light meter to read percent busy.

Many moons ago, when I worked in a big mainframe shop, I had a boss's,
boss's, boss who didn't believe the machine's up-time reports the comp
genter guys were giving him.  He believed that total machine availability
included the hardware, the OS (OS/MVT if you really must know.), the I/O
channels - etc., and the application server (IMS - ugh.).  So ..... he
had someone tape a photo-transistor to the poll led on our local cluster
controller. This was in turn hooked to a strip-chart recorder upon which
a clerk came in three times a day to record the date and time.  Needle
on the right - everything ipsy-pipsy - needle on the left - no-polling -
wavering line - trouble coming.  A real truth meter.

Also in ESS-COs ten or so years ago there was an x-y CRT hanging off the
address bus of the processor.  An experienced frameman could tell at a
glance what the switch was doing and if it was in trouble.


Joe Wood
lznv!jlw