Re: Pacemark GS memory card

[dempson@atlantis.actrix.gen.nz (David Empson)]

In article <4meak2$7k4@vixen.cso.uiuc.edu>,
Jonathan E. Isom <jisom@firefly.prairienet.org> wrote:
> can anyone tell me if 9 or 3 chip simms will work in it?

Yes.

Any mention of "9-chip" and "3-chip" SIMMs are just advertising
gimmicks.  8-chip or 9-chip SIMMs use RAM which is one bit wide, while
2-chip or 3-chip SIMMs use RAM which is four bits wide (plus one bit
for parity in the case of a 3-chip SIMM).

The items that are important are:

1. The SIMM has the correct number of pins: you can only use 8-bit SIMMs
   (30 pins), not 32-bit SIMMs (72 pins).  It makes no difference whether
   or not the SIMM has parity - it is not used by the Apple II.

2. The RAM on the SIMM must be fast enough.  For a IIgs, use 120 ns or
   faster RAM, to be on the safe side (150 ns should work, but it is better
   to be safe than sorry).

3. The RAM must support CAS-before-RAS refresh (all should).


-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand