Path: utzoo!utgpu!attcan!uunet!super!rminnich
From: rminnich@super.ORG (Ronald G Minnich)
Newsgroups: comp.arch
Subject: Re: VAX Memory Test
Message-ID: <609@super.ORG>
Date: 10 Aug 88 13:38:09 GMT
References: <3300032@m.cs.uiuc.edu> <12849@mimsy.UUCP> <1743@swlabs.UUCP> <167@vertical.oz>
Sender: uucp@super.ORG
Reply-To: rminnich@metropolis.UUCP (Ronald G Minnich)
Organization: Supercomputing Research Center, Lanham, MD
Lines: 12

In article <167@vertical.oz> greg@vertical.oz (Greg Bond) writes:
>Usually called memory scrubbing.  A task for the null process?
>And is it usually implemented in hardware or software?  Do hardware
>implementations automagically write back corrected value?
At burroughs it was called healing. The memory controller did it
all automatically. ON a cheaper machine there is no reason
(i can think of) that you couldn't do it in software- just read the 
value and write it back. Course, if you have snooping caches 
or channels or other things that might whomp memory that 
has side effects, whereas on the burroughs machines which did it in 
hardware that was not an issue.
ron