Path: utzoo!attcan!uunet!mailrus!uflorida!unf7!tlvx!sysop
From: sysop@tlvx.UUCP (SysOp)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Parity Checking / ECC RAM on the A3000
Summary: parity again?!
Keywords: parity error detection and correction, marketability
Message-ID: <321@tlvx.UUCP>
Date: 28 May 90 23:46:15 GMT
References: <756@bilver.UUCP> <1990May27.101258.24470@zorch.SF-Bay.ORG>
Organization: Temporal Vortex BBS of Jacksonville, Florida
Lines: 61

In article <1990May27.101258.24470@zorch.SF-Bay.ORG>, xanthian@zorch.SF-Bay.ORG (Kent Paul Dolan) writes:
> In article <756@bilver.UUCP> alex@bilver.UUCP (Alex Matulich) writes:
> >
> >However, the fast RAM chips are replaceable by the 4 meg variety.  You can
> >stick 16 of them in the A3000.  That's a potential for 16 parity errors
> >per day!
...
[story about Cray 1 deleted]
> The Amiga 3000 is capable of holding (at least supporting) much more memory
> than a Cray 1, and the size of gates in modern memory is much smaller and
> thus they are more susceptable to alpha radiation induced parity errors than
> were the gates of the Cray memory.

Even "more susceptable"?  Ok, why?  How?  If it were really that bad, then
people using the A3000 now should be at least occasionally noticing weird
things happening, right?  But are they?  What about my A1000 with 2.5 megs?
(Of course, I don't have parity, so how can I tell?  Sigh.)

> 
> To take an Amiga seriously as a commercial machine in the "workstation,
> large memory" market, I'd guess error correcting code will turn out to be
....
> But then, what do I know after 29 years in the field about what people who
> buy the machines look for in a large processor?  My computer purchases were
> limited to a couple of million bucks worth, down in the noise level in the
> marketplace.  ;-)

It's not that I don't believe you, but... I would like some real concrete
information.

Explain to me this:  I've used a 20 MHz AST 386 for at least 1.5 years at
work, the last year or so with a total of 3 megs.  While I've had problems
(I AM developing software :-), no parity errors have ever appeared.  Is it
possible that the AST has no parity checking, or is it possible that parity
errors are much more rare than some people think?

Sure, I see nothing wrong with making a system more "reliable", but if it's
not really doing any good, then it's a waste of time and money.  If parity is
truely necessary, perhaps concrete proof is going to be needed to convince
others that it's necessary.  The Commodore engineers read these newsgroups, and
I'm sure they've thought about this.  Since there doesn't seem to be a large
cry for it, and Commodore doesn't think it's necessary, just one or 2 people
saying, "You need Parity or else you're not a Real Machine (TM)," isn't going
to change anything.  This isn't a flame, it's just that there were already
a lot of messages on this subject, and as any subject, past a certain point,
you need to go beyond opinion and start with the hard cold facts.  Since I
don't know the rate of errors, I could learn something myself.  (Earlier
messages didn't convince me either way; my mind is still open to debate.
Convince me!!! :-)

If it's only the denser chips that have the errors, then the question is,
will such memory improve with technology such that this won't be a concern,
like the less-dense chips (after some period of time)?

> 
> Kent, the man from xanth, now zooming to the net from Zorch.
> (xanthian@zorch.sf-bay.org)

--
Gary Wolfe
uflorida!unf7!tlvx!sysop, unf7!tlvx!sysop@bikini.cis.ufl.edu