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Date:      Mon, 27 May 1996 14:26:59 -0700 (MST)
From:      Terry Lambert <>
Subject:   Re: Re(2): SCSI hostadapter
Message-ID:  <>
In-Reply-To: <"1443-960526225554-A900*/G=Andrew/S=Gordon/O=NET-TEL Computer from "" at May 27, 96 01:30:12 am

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> > Reminds me: does anybody have any information about the 53C400?
> > 
> > I've got a couple of these boards sitting on a shelf, they used to
> > accompany HP ScanJets.  I don't think they will be anything that can
> > be called performant, but just out of curiosity...  Perhaps they are
> > good enough to recommend them to someone who needs an adapter for an
> > Archive Viper 150 or so (which i'd recommend rather than those floppy
> > tape crap).
> As it happens, I was trying to put a system together yesterday, using mostly old junk I had lying around.  Since I didn't care about disc performance, and I had an old SCSI drive plus a 53C400 adapter handy, I thought I would use those (booting off floppy with some suitably hacked bootblocks).
> The adapter originally came with a scanner, (but not an HP one) and contains just the 53C400 plus an LS245 buffering the databus and some SCSI termination resnets.  Curiously, the nca driver probes the card as a NCR-5380 despite the fact that the chip on the card is clearly labelled as a 53C400A.  However, hacking the driver to probe only for 53C400 (it normally probes 5380 first) caused the card not to be probed at all.
> This particular card does not support interrupts (it doesn't even have any fingers on the connector for any of the IRQ lines).
> For the hard drive, it seems to work reliably, but is _very_ slow - here are some bonnie results (and results for the same motherboard/drive but with a 2940 instead, for comparison):
>          -------Sequential Output-------- ---Sequential Input-- --Random--   
>          -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---   
>       MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU  /sec %CPU   
> ncr   16   105 89.0   110 10.8    55  1.3   109  8.4   111  5.5   9.6  8.7   
> 2940  16   560 28.4   553  7.7   266  6.5   612 28.7   605  8.3  24.8  3.8   
> (the drive is an old SCSI-1 device, async transfers only.  CPU is AMD 486/100).

This is typically an artifact of having the interrupt set incorrectly.

I'd caution you that it's also possible that it's just a dog-slow
interface, so there may be nothing to be done about it.

					Terry Lambert
Any opinions in this posting are my own and not those of my present
or previous employers.

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