Re: GS-RAM Plus Exp.

[bpvh@primenet.com (Bradley P. Von Haden)]

nathan@visi.com (Nathan Mates) wrote:

>Al Boisvert <aboisvert@snac.mv.com> wrote: 

>>Can anyone explain why an Applied Engineering GS-RAM Plus Memory
>>Expansion card fully populated with 6 megs of RAM will always
>>hangup (Crash) when booting Sys.6.0.1 from a hard Drive?

>   Which HD controller do you have? [You didn't say]. What's more
>than likely happening is that above 4MB of RAM, DMA is usually not
>possible without some hacks that the GS-RAM+ does not do. If you
>have a DMA capable HD controller trying to DMA files in off disk
>into memory that's not DMA happy, things'll most likely get
>corrupted in RAM. (And hopefully crash before any corrupted stuff
>can be written to disk)

There are different versions of the AE GS-RAM Plus card (A through E)
with the first two or three not DMA compatible at all.  So, if you
have a Rev. A or B (and possibly C), the card is not DMA compatible
and DMA must be turned off on the SCSI card.

For Rev. D and E cards, I have heard about this incompatibility
problem here on c.s.a2 and on GEnie but it just does not happen with
my AE GS-RAM Plus (Rev D) memory card (fully populated to 6 megs) and
my Apple HS SCSI card (DMA is on).  In fact, this has not been a
problem in two different ROM 01 setups and two different ROM 03
setups (4 different GS-RAM Plus cards and two different Apple HS SCSI
cards).  My system software does run over 2 megs.

Copying large blocks of files is definitely faster with a 4 meg
memory card (CV-Tech) in the system rather than the GS-RAM Plus card
but I do like having the extra memory.

****                Maintainer of the CD CLUB FAQ                ****
****               http://www.blooberry.com/cdfaq/               ****
****      ftp://ftp.primenet.com/users/b/bpvh/cdclubfq.txt       ****
**** bpvh     Internet: bpvh@primenet.com      GEnie: B.VONHADEN ****
**** Posted by an Apple IIgs using my own Proterm 3.1 File Macro ****