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From: jerem@tekgvs.UUCP
Newsgroups: comp.sys.amiga
Subject: Re: Amiga: Which replacment OS?/UN*X ??
Message-ID: <2363@tekgvs.TEK.COM>
Date: Mon, 15-Jun-87 01:19:08 EDT
Article-I.D.: tekgvs.2363
Posted: Mon Jun 15 01:19:08 1987
Date-Received: Thu, 18-Jun-87 00:37:54 EDT
References: <600@gryphon.CTS.COM> <1705@vdsvax.steinmetz.UUCP> <1576@stb.UUCP> <1765@vdsvax.steinmetz.UUCP> <785@omepd>
Reply-To: jerem@tekgvs.UUCP (Jere Marrs)
Distribution: world
Organization: Tektronix, Inc., Beaverton, OR.
Lines: 33

In article <785@omepd> hah@isum.UUCP (Hans Hansen) writes:
>In article <1765@vdsvax.steinmetz.UUCP> barnett@ge-crd.arpa  (Bruce G Barnett) writes:
>>>	I may be wrong, but isn't that how the CSA 020 board works?
>>
>>I may be wrong, but I don't understand how the csa 020 board can have
>>32 bit wide data access to the backplane. I would eventually like the
>>ability to have a 32 bit wide backplane machine with 32-bit DMA etc.
>>

>I believe you will find that the CSA board uses a 32 bit expansion bus
>that starts at 16M (0x0000010000000000).

	The CSA board uses the standard Zorro I backplane (16-bits) and
the 32-bit bus is physically separate and not part of the backplane. My
1 Meg of 32-bit memory starts at 7f000000 and ends at 7f0fffff. The 32-bit
address space lies above the 24-bit address space of the 68000. Thus, DMA
chip access to this address space will require some cleverness on C-A's
part.

	While I have y'all on the horn, I have a question. I thought about
further expansions of my memory with, say, a Zorro I board from, say, ASDG.
But then I thought: Hmm. I would have no control over where code and data
are loaded in a program. I would guess that MEMF_FAST would mean  either
the 16 or the 32-bit memory. Since there is a factor of four in execution
speed in the 32-bit memory, I would want to selectively use it. Maybe I
should save my, uh, pennies for more 32-bit RAM.

					-Jere

Jere M. Marrs
Tektronix, Inc.
Beaverton, Oregon
{U-name-it}!tektronix!tekgvs!jerem