Subject: Re: Sirius Ram IIgs Questions
From: Paul Schultz <pschultz@med.wayne.edu>
Date: Sun, Nov 8, 1998 7Ç48(H
Message-id: <Pine.SOL.3.96.981108094056.1137A-100000@moose>

On 6 Nov 1998, Supertimer wrote:

> 
> I've read about this in the FAQ and on csa2 too.  I think it has
> to do with the way memory is mapped.  It might be that the
> Sirius firmware has problems differentiating the two IIGS
> models.  If so, then it may act in a ROM 01 "mode" whatever
> IIGS it is in.  That means you will get all memory >256k from
> the memory expansion slot (the Sirius).  As you can imagine,
> this will cause a 768k memory "hole" somewhere in the 8MB
> range.  

First, the problem with the Sirius was theoretically with the
version 1 card (this card has no jumpers and would 'sense' the
number SIMMs present). Adding the 8th SIMM would cure the problem.
However, it used the full 1 MB on the ROM 3 motherboard. This
goes for the version 2 card (a more traditional card with jumpers
which set the SIMM configuration) also. By the time the version 2
card came out SIMMs were so cheap that Alltech (i.e. Tony) thought
it would be less of a hassle to just ship with all 8 MB installed
regardless if you had a ROM 1 or ROM 3 IIgs.

Like I mentioned, theoretically the problem was solved with the
version 2 card. But, my own experience and that of others here on
csa2 and on Delphi has shown that leaving the last socket empty
still results in less stable behaviour.

Paul.

pschultz@med.wayne.edu
Paul Schultz