Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uwm.edu!ogicse!jmeissen
From: jmeissen@ogicse.ogi.edu (John Meissen)
Newsgroups: comp.sys.amiga
Subject: Re: New GVP Controller questions
Message-ID: <12326@ogicse.ogi.edu>
Date: 21 Sep 90 21:23:58 GMT
References: <9009201538.AA28646@ucbvax.Berkeley.EDU> <12291@ogicse.ogi.edu> <1990Sep21.163715.3423@jarvis.csri.toronto.edu>
Organization: Oregon Graduate Institute (formerly OGC), Beaverton, OR
Lines: 30

In article <1990Sep21.163715.3423@jarvis.csri.toronto.edu> leblanc@eecg.toronto.edu (Marcel LeBlanc) writes:
>I think the person you spoke to may not have been very clear.  Unless GVP
>has completely redesigned their SCSI controller, it DOES NOT DMA to the
>Amiga's memory (the 2090A does).  The GVP controller that I have writes to a
>cache (hence their misleading 'DMA to on-board memory' claim), which must
>then be copied to it's final destination by the CPU.  The GVP controller is

Yes, GVP "has completely redesigned their SCSI controller." That is one of
the important features of the Series-II controller. This version, UNLIKE the
earlier version, does do true DMA anywhere in the Zorro address space.

The memory on the board is autoconfigured into the Zorro address space, and 
is part of the Amiga Fast Ram. In addition, it is supposed to be set up in
a dual-port configuration (I don't know the details) so that if your Fast Ram
is on the board it can transfer directly into that memory without having to
deal with bus arbitration on the Zorro bus (assuming that's where the drive's
buffers are allocated...I assume they handle that somehow; the documentation
is quite sparse).

>
>Marcel A. LeBlanc  --  Electrical Eng. Computer Group, Univ. of Toronto
>-----------------------------------------------------------------------
>leblanc@eecg.toronto.edu		else: uunet!utcsri!eecg!leblanc


-- 
John Meissen .............................. Oregon Advanced Computing Institute
jmeissen@oacis.org        (Internet) | "That's the remarkable thing about life;
..!sequent!oacis!jmeissen (UUCP)     |  things are never so bad that they can't
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