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From: kent@xanth.UUCP (Kent Paul Dolan)
Newsgroups: comp.sys.amiga
Subject: Re: Chip RAM
Message-ID: <2852@xanth.UUCP>
Date: Mon, 19-Oct-87 20:23:19 EDT
Article-I.D.: xanth.2852
Posted: Mon Oct 19 20:23:19 1987
Date-Received: Wed, 21-Oct-87 06:50:48 EDT
References: <1821@gryphon.CTS.COM> <2719@xanth.UUCP> <2537@cbmvax.UUCP>
Reply-To: kent@xanth.UUCP (Kent Paul Dolan)
Organization: Old Dominion University, Norfolk Va.
Lines: 57
Keywords: 1/2 M, 1M, 4M, PAL's
Summary: Is there still a smidgeon of hope for 2 meg from Fat Agnes?

In article <2537@cbmvax.UUCP> grr@cbmvax.UUCP (George Robbins) writes:
>In article <2719@xanth.UUCP> kent@xanth.UUCP (I wrote:)
>>
>> [stuff you already saw, omitted, except for a bit of context - it wasn't
>> THAT brilliant a posting!]
>>
>> Now we're being told that 1 meg is the answer, and that two meg can't
>> be attained for technical reasons.  What gives?
>> 
>[George answers:  (Thanks, George!  Love ALL you Amiga net reps!)]
>The Fat Agnus chip used in the A500 and now the A2000 can only internally
>address 512K of chip memory, however the processor side access supports
>this 512K plus an additional 512K for external expansion.  The actual
>outputs are 9 multiplexed address pins and one RAS line for each of the
>two 256K*16bit banks of DRAM's.  To provide addressing for 2MB of "chip"
>memory would require yet another address input and either external
>decoding of the RAS signals (timing problems) or the use of 1MB chips
>(big cost problems) or more pins for RAS lines (packaging problem).
>Anyhow, the motherboards in the A500 and A2000 are wired up to support
>Fat Agnus and a total of 1MB internal RAM plus whatever you want in the
>way of external RAM.

1) This sounds like CHIP ram is getting better, still at 512K, but
internal memory is bigger.  That I think we knew already.

2) This almost sounds like a bit of hope for making CHIP ram bigger;
If I felt like springing for 1 meg chips (I've never figured out why
this should work, plugging one size chip in place of another; pure
black magic to me) "no matter what the cost", does the A2000 now, or
could it with a reasonably cheap upgrade, allow for more CHIP ram?
After the recent notes on the price of 1K x 1K color monitors, I have
to admit I'm not yet in the market for one of them.  On the other
hand, a little deeper color lookup table (state of the art last time I
bought a high end terminal was 11 bits, is it twelve yet?) (nine bits
would be SO GREAT!) and, more important, room for more screens and
windows, seem to be within reach (am I right?) without more than a
little speed up of the system clock, if the graphics chips can support
it.  So, George, does your note mean that _I_ can increase my chip ram
(presuming I take advantage of the A2000 offer instead of diving right
up into a falling stock market - whew - what a day!  You know what the
PEs look like NOW!?!  Haven't seen the paper after today, of course,
but as of Friday's, Commodore was going up in a down market - news
about the rapidly emptying shelves in the stores must have leaked out
- who snitched?  ;-) Way to go guys!), or that you COULD?  In either
case, I'm interested.  Graphics is my life!

Kent, the (totally weird) man from xanth.

Running for president on a pound of caffine, an ounce of sense, and a
program of increased exploration and exploitation of space.  Support
your (probably non-existant - get busy!) local branch of the Birthright
Party:  "The birthright of mankind is the stars!"

Hey, it's better than dwelling on your stock portfolio; at least here
you've got a chance for a laugh or two. ;-)  Yum!  Eat them plastic
chickens, brethern!  Call me when I'm elected; 'til then, I'm going to
take a nap.