Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!uunet!cbmvax!daveh
From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: GVP 68030 board + bridgeboard == HUH?
Message-ID: <19644@cbmvax.commodore.com>
Date: 8 Mar 91 18:11:08 GMT
References: <709.27d4f185@vger.nsu.edu>
Reply-To: daveh@cbmvax.commodore.com (Dave Haynie)
Organization: Commodore, West Chester, PA
Lines: 46

In article <709.27d4f185@vger.nsu.edu> manes@vger.nsu.edu ((Mark D. Manes), Norfolk State University) writes:
>Greetings one and all.

>I seek information.

>I know that the Amiga 2000 is limited to 9mb of 16 bit memory.  

The important thing to realize is that the memory range allocated for Zorro II
boards is 8.5 megabytes long.

>I also _thought_ that if you wanted to have a bridgeboard
>and you wanted to go above 6mb of memory you could add an accellerator
>board and 32bit memory.  I _thought_ that this 32bit memory would be
>placed so that a bridgeboard would not interfer.  I guess this is
>not correct.

That depends on the accelerator.  Some accelerators, like the A2630 and 
probably the GVP, use Zorro II autoconfiguration protocols to add their memory
to the system, even though they are not real Zorro II devices.  This allows
hard disks to access that memory, and makes it behave pretty much like any
supported add-in memory, only faster.  It is also possible for a 32 bit board
to support memory that's not in the Zorro II memory range, but that usually
makes it nonstandard, and always means that it can't be reached by hard disk
DMA.  It is really up to the designer of the 32 bit coprocessor board to 
chose which makes the most sense for their intents.

>We (Video Computer Resources) attempted to put a 33mhz GVP 68030
>board in a Amiga 2000 with a AT Bridgeboard.  The customer purchased
>the 8 megabyte version of the board.  We can get everything to work
>if we pull 4 megabytes of the 32bit memory.  If we leave all 8 
>in, the Janus software fails with a 'unable to open library' error
>message.

That memory is in fact using the Zorro II autoconfig space.  It may not help,
but GVP is currently advertising that their 50MHz 68030 board can support 
either 8 or 20-something megabytes on its daughterboard.  I suppose they would
map some as Zorro II memory, some as either A3000 motherboard or Zorro III
memory (assuming they wanted to appear somewhat standard).

> | \/     |   Mark D. Manes   "Mr. AmigaVision,  The 32 bit guy"


-- 
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
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	"What works for me might work for you"	-Jimmy Buffett