Re: GS super ram memory card (4mb?)

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

simon <eco@globalserve.net> wrote:

> I have this Pacemark Technologies Inc. (model - GS Super Ram) memory
> card for an Apple //gs.
> 
> It takes 30 pin simms, and has 4 slots, and can be set (I think) to 1,
> 2, or 4mb combinations via a 2 pole dip switch.
> 
> Is there any associated software, drivers, diagnostics for this card?

If there was any software, it would only have consisted of a memory test
program.  You don't need drivers for a RAM card.

> Should ram chips be parity type?

The IIgs doesn't use parity, so you don't need 9-bit SIMMs, but the
parity bit will be ignored, so it doesn't matter either way.

> Is it possible to bump it up to 8mb with 2 mb chips?

No.  The memory decoding is handled by the motherboard, which only
supports row sizes of 256 KB and 1 MB (and they cannot be mixed), with a
maximum of four rows.

8 MB cards have additional circuitry to decode the bank address, at the
cost of DMA compatibility.  I've never heard of an Apple IIgs RAM card
which supported 512 KB or 2 MB SIMMs.

> DIP switch settings?

I can't answer that one.  There will only be three valid combinations,
but they will depend on the other circuitry on the card.  If you install
four SIMMs, you can experiment to find the combinations which provide
access to 1 MB, 2 MB and 4 MB.  (The illegal combination may result in
the machine appearing to have 1 MB or 2 MB, but it may be unreliable.)

-- 
David Empson
dempson@actrix.gen.nz