Newsgroups: comp.parallel
From: is@groucho.dev.uga.edu (Bob Stearns)
Subject: Re: need help on HEP computer
Organization: University of Georgia, Athens
Date: 25 Oct 1995 15:38:04 GMT
Message-ID: <46llks$jjj@usenet.srv.cis.pitt.edu>

In article <46g9vl$36p@usenet.srv.cis.pitt.edu> "joanne (j.) pilkington" <joannep@bnr.ca> writes:
>I am doing an assignment for a masters course and I am having
>trouble because all the books are out of the library. Could
>anyone tell me what new architectural concepts were introduced
>by the HEP computer?
>
>Thanks in advance,
>Joanne

Since we had a HEP on our computer room floor for a while, I suppose I
am qualified to answer this.

The HEP was a shared memory multiprocessor with three major improvements
(innovative technologies) over its competitors:
  1. Every memory cell was a semaphore with Read-when-full and write-
     when-empty instructions for each word.
  2. Memory was asynchronously attached to all the processors using a
     time-stamped request packet and a series of three way switched which
     routed the "oldest" inbound packet closer to its destination while
     routing the other packets as best as possible, including sending it
     back to its source.
  3. Memory and processor cards (18" square!!!) could be hot-swapped
     without failing the whole system, and often without failing any
     task.

If you have any further questions I would be glad to answer them.
-- 
Bob Stearns
University of Georgia
is@groucho.dev.uga.edu
(706)542-5110

