Path: utzoo!mnetor!uunet!husc6!bloom-beacon!tut.cis.ohio-state.edu!mailrus!ames!pioneer!eugene
From: eugene@pioneer.arpa (Eugene N. Miya)
Newsgroups: comp.arch
Subject: Re: Lights on computers (was Re: Cray architecture)
Message-ID: <6633@ames.arpa>
Date: 29 Mar 88 17:26:46 GMT
References: <7762@alice.UUCP> <418@ole.UUCP> <3216@phri.UUCP> <1574@osiris.UUCP> <1461@ut-emx.UUCP> <3671@medusa.cs.purdue.edu>
Sender: usenet@ames.arpa
Reply-To: eugene@pioneer.UUCP (Eugene N. Miya)
Organization: NASA Ames Research Center, Moffett Field, Calif.
Lines: 23
Keywords: LED, parallel computers.

I saw the MIDAS multiprocessor at LBL some years ago solving a divide
and conquer problem (chess problem?).  It was interesting to watch
the asynchronous processors each run similar light patterns then
converge on a solution.

Cray-2s have a set of LEDs on the top which you can read thru the transparent
fluorinert and window.

What was interesting about lights and sound was that the people working
on the MIDAS developed abilities to pattern recognize problems on the
basis of looking at the lights (as did numerous good PDP-11 programmers
and IBM light boxes of the 360 era).  Not enough people can see a 2 to
develop this type of ability, but there might be CRI people who can.
A similar situation was shown to me while visiting Xerox PARC: an idle
loop bitmapped icon could tell some Dorado programmers what was wrong in
hardware.  We are not a science yet, but it's interesting.

From the Rock of Ages Home for Retired Hackers:

--eugene miya, NASA Ames Research Center, eugene@ames-aurora.ARPA
  "You trust the `reply' command with all those different mailers out there?"
  "Send mail, avoid follow-ups.  If enough, I'll summarize."
  {uunet,hplabs,hao,ihnp4,decwrl,allegra,tektronix}!ames!aurora!eugene