[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: odd cards
- Subject: Re: odd cards
- From: "Paul Grammens" <grammens@svn.net>
- Date: 2000/07/10
- Newsgroups: comp.sys.apple2
- Organization: Silicon Valley North (http://www.svn.net)
- References: <20000708145825.25459.00000559@ng-fg1.aol.com> <8k88sd$rnj$1@nnrp1.deja.com> <SXT95.29509$FQ.2746896@news0.telusplanet.net> <8kan2v$b17$1@nnrp1.deja.com> <090720001225087278%news001@nospam_macgeek.org>
Bryan Villados <news001@nospam_macgeek.org> wrote
>
> It could also be parity versus non-parity. The OctoRAM card could very
> well not like parity SIMMs, which PC's traditionally use. The
> Macintosh, such as the Macintosh Plus and the SE, uses non-parity
> SIMMs. And you can't use parity SIMMs in the earlier Macintosh
> computers.
>
I have used 9 chip and 3 chip SIMMs from PC's in Macs from the Plus on, with
no problems. The Macs just don't use the parity bit. I'd expect the OctoRAM
card to work the same.
I think these myths come about when someone puts a bad SIMM in a computer
and has problems, then figures that type of RAM doesn't work.
I don't think the computer can tell the difference between the 2 or 3 chip
and 8 or 9 chip versions. The 3rd/9th chip provides the parity bit, not
used by Macs and probably Apple II RAM boards. 4 of the remaining chips
from the 8 or 9 chip SIMMs are the equivalent of 1 of the chips on the 2 or
3 chip SIMMs. The computer doesn't know or care that they are packaged in
one chip instead of 4.
So: bad SIMMs of any kind won't work. If you are having problems, try to get
another SIMM or set of simms. 1 meg SIMMs only cost $1 or so, now. You can
find the bad one by the process of elimination.
-Paul