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Date:      Fri, 14 Apr 1995 11:42:47 -0700 (PDT)
From:      "Rodney W. Grimes" <rgrimes@gndrsh.aac.dev.com>
To:        nate@trout.sri.MT.net (Nate Williams)
Cc:        freebsd-scsi@FreeBSD.org
Subject:   Re: SCSI target
Message-ID:  <199504141842.LAA01339@gndrsh.aac.dev.com>
In-Reply-To: <199504141840.MAA29401@trout.sri.MT.net> from "Nate Williams" at Apr 14, 95 12:40:20 pm

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[cc: trimmed to scsi list]
 
> > > > However, the only host adapter that supports this is the Adaptec
> > > > 1542B.  The 1542C will hang the bus big time if you put it into
> > > > target mode, so I've locked it out.
> > > 
> > > Great!  But one of my 1542B's bit the dust about a month ago so now
> > > I only have one of them :-( :-(.
> > 
> > I only have one also.
> > 
> > (...)
> > > If you loose that card and still need one to work with I can arrange
> > > to put an NCR 53C810 controller in your house on a permanent loan
> > > basis.
> > 
> > I'm not planning on adding the support to the firmware - initially,
> > I could probably use the 1542B more than the 810 for test.  If anyone
> > has a 1542B sitting in a closet (as I did until recently) feel free to
> > send it.
> 
> If anyone has a controller which is better than a 1542B for a straight
> ISA box (No VLB frills), I'd be willing to trade it for my 1542B.  I'm
> not real pleased with the performance out of the one I have, and would
> certainly be willing to trade up to get better disk performance.  (I'm
> getting about 60% of what I could with my PD2100S)

Your not going to get much more out of *any* ISA controller.  The 1542CF
will do a little better, but basically your problem is the speed of
the ISA bus bus mastering (typical max is 5MB/sec *burst*, sustainted
goes down to about 3.7-4MB/sec).  You should be getting about 3MB/sec
out of your 1542B and I have not seen anthing better on ISA.  You'll
need to go VLB or PCI to get the numbers up there.  



-- 
Rod Grimes                                      rgrimes@gndrsh.aac.dev.com
Accurate Automation Company                   Custom computers for FreeBSD



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