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From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga
Subject: Re: Too good to be true?
Message-ID: <15831@cbmvax.commodore.com>
Date: 13 Nov 90 17:39:46 GMT
References: <5607@crash.cts.com>
Reply-To: daveh@cbmvax.commodore.com (Dave Haynie)
Organization: Commodore, West Chester, PA
Lines: 29

In article <5607@crash.cts.com> critical.mass@pro-graphics.cts.com (Peter Altamore) writes:

>On page 134 (lower right) The Grapevine Group is advertising Megachip 2000.
>This is something I thought was not possible, 2 megs Chip RAM on a 2000!?
>They say to call for the price (I haven't yet) and include a '2 MB Agnus,
>more RAM, PC board, full instructions.'  Anyone know what they're doing and
>if it's even slightly compatible with anything (they don't say either way
>in the ad)?  

They could build a "tower" board, with the extra 1Meg and use the 8372B, the
version of Agnus from the A3000.  That part can handle 2 Megs of RAM, but 
unless the memory is organized as 16 1Megx1 parts, there is additional external
logic necessary.  The standard A2000 Agnus, 8372A, manages two separate 512K
chunks, so both don't absolutely have to be there for proper functioning (as
on the A500).

>The 3000 gets 2MB Chip due to the 32-bit path, right?  

No.  Since we needed some external logic anyway for support of 256K x 4 DRAMs 
with the A3000, and since Chip memory was slow, it just made sense to organize
the A3000's memory as 32 bits wide.  But that has nothing to do with the amount
of Chip RAM the A3000 can address; that's left up to the Agnus chip.

>      UUCP: crash!pro-graphics!critical.mass    | Critical Mass Software

-- 
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
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	Standing on the shoulders of giants leaves me cold	-REM