Path: utzoo!attcan!uunet!ficc!karl
From: karl@ficc.uu.net (karl lehenbauer #)
Newsgroups: comp.arch
Subject: Re: Cray Quotations
Message-ID: <2523@ficc.uu.net>
Date: 21 Dec 88 18:59:52 GMT
References: <2496@ficc.uu.net> <8841@sequent.UUCP>
Organization: Ferranti International Controls
Lines: 25

In article <8841@sequent.UUCP>, rgb@sequent.UUCP (Bob Bond) writes:
> I have heard "Parity is for farmers" attributed to Cray.
> Does anyone know if this is accurate?

I know the CDC 6600, Cyber 70 and 170 series machines did not have parity.
From what I heard Seymour felt that parity didn't buy much -- detection
of a parity error meant death for the running program at the least and
maybe even for the OS.  There was always the chance that the parity error 
would occur in the parity bit, causing a parity error when there was
no actual data error.

The Cray line has error correction/double error detection, an innovation
(not pioneered by them) that buys a good deal more than parity detection
alone, hence it's in there.

Disclaimer:  It was a long time ago, far far away, and may have been
 apocryphal to begin with.

Another Seymour quote:
	"Thank heaven for startups.  Without them there'd never be any
	innovation."
-- 
-- uunet!ficc!karl	"The greatest dangers to liberty lurk in insidious
-- karl@ficc.uu.net	encroachment by men of zeal, well-meaning but without 
			understanding." -- Justice Louis O. Brandeis