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From: toddpw@tybalt.caltech.edu (Todd P. Whitesel)
Newsgroups: comp.sys.apple2
Subject: Re: RAM expansion questions
Keywords: SIMMS, cheap, card
Message-ID: <1990Aug16.015542.19223@laguna.ccsf.caltech.edu>
Date: 16 Aug 90 01:55:42 GMT
References: <631@servio.UUCP> <1990Aug14.182945.18045@laguna.ccsf.caltech.edu> <1990Aug15.223424.20746@utstat.uucp>
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Organization: California Institute of Technology
Lines: 54

philip@utstat.uucp (Philip McDunnough) writes:

[ in response to this, which I wrote ]
>>The GS Sauce is the only card I am aware of that takes 4 1 meg SIMMs.

>There is also a card put out by Harris Labs(which may be the same card!) which
>accepts Mac Simms. However, I do not know if this card is "DMA compatible".
>Does anybody have any firm information about this card?

Yes, I do -- I bought one. The GS Sauce is made by Harris Labs, it accepts
SIMMs (1,2,4 256k, or 1,2,4 meg) and is 100% DMA compatible, period. Harris
did the right thing and made the card simple -- it supports exactly those
configurations that Apple steadfastly guarantees will work under all conditions
and ONLY those configurations. AE's cards all do something more than what
Apple guarantees, but they have to forfeit total compatibility in the process.
That's why you have to make sure your AE card is upgraded properly. I have two
megs in my GS Sauce and it works fine -- ok, so I've only had it for a week,
but I have much more confidence in it than I would in an AE memory board.

[ I also wrote, and stand this ]
>>I strongly advise you NOT to buy any GS memory boards from AE.

>Why are you advising against AE? I have a GS RAM+ card and it "seems" to
>work with my ROM03,TWGS,DMA SCSI card,...I have my own thoughts re AE but
>they do supply quite a few AppleII peripherals. 

AE has gone severely downhill over the last few years, I think. I am very
satisfied with the first things i bought from them, but lately their products'
compatibility problems and just their whole attitude has turned me off. I am
quite a bit miffed after paying $100 for a Sonic Blaster, whose software sucks
and has never been upgraded, whose digitizer input is totally unusable, and
whose technical support is effectively nonexistent.

>Do you know if the AE GS RAM+ card(upgraded for the ROM03) is DMA compatible?
>Mine seems to work, but I only have 1 meg in it and fear the consequences of
>adding more!

Here's the scoop. If you have more than four sets of chips in the thing then
you *might* have problems. The GS RAM+ takes 1 meg chips, so you've only got
one set in there now. Taking it up to four megs is no problem, unless AE did
something really stupid. Going beyond four megs relies on AE's hardware hacking
for the DMA compatibility to work, but (listen up) Apple's DMA card driver
doesn't use DMA on memory that is above the four meg mark. If you have four
megs or less of main memory then all of it should be DMA compatible (UNLESS you
use 256k chips in a >4 row card) and it gets DMA'd to. Any memory from 04/0000
to 07/ffff is accessed by a software transfer loop. Your TWGS will speed that
up, so you probably won't notice the difference. Besides, when you have four
megs or more, the system almost never has to purge or compact memory, so things
go much faster -- less housekeeping and disk access is necessary.

Hope this last wasn't too confusing.

Todd Whitesel
toddpw @ tybalt.caltech.edu