Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!uakari.primate.wisc.edu!sdd.hp.com!hplabs!hpl-opus!hpnmdla!darrylo
From: darrylo@hpnmdla.HP.COM (Darryl Okahata)
Newsgroups: comp.arch
Subject: Re: Workstation Data Integrity
Message-ID: <7410001@hpnmdla.HP.COM>
Date: 4 Aug 90 23:03:11 GMT
References: <1990Aug3.204358.330@portia.Stanford.EDU>
Organization: HP Network Measurements Div, Santa Rosa, CA
Lines: 40

In comp.arch, jackk@shasta.stanford.edu (Jack Kouloheris) writes:

> I'm a bit puzzled by the lack of any type of memory error detection/
> correction on many workstations and high-end PCs. These workstations
> are beginning to have memories that rival or exceed those of
> the previous generation of minicomputers, which almost always used
> some sort of ECC protection. Do manufacturers feel that it isn't needed
> any more ?

     Just as a data point, ECC memory is available as an option on
Hewlett-Packard workstations.

     For those HP workstations with only parity-checked memory, the
system administrator can choose one of three actions upon the occurrence
of a parity error:

1. Print a "Parity error" message to the console.

2. Print a "Parity error" message to the console, plus:

	If user state, it kills the current process (which may not
	always be the process which caused the error, as with a DMA
	card) and prints an error message to the tty.

	If supervisor state, it panics with a "parity error" message to
	the console.

3. Always panics with a "parity error" message to the console.

The last one (#3 above) is the default action (with the other actions,
data corruption could occur depending on where the RAM parity error
occurred).

     -- Darryl Okahata
	UUCP: {hplabs!, hpcea!, hpfcla!} hpnmd!darrylo
	Internet: darrylo%hpnmd@hp-sde.sde.hp.com

DISCLAIMER: this message is the author's personal opinion and does not
constitute the support, opinion or policy of Hewlett-Packard or of the
little green men that have been following him all day.