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Date:      Mon, 27 May 1996 14:26:59 -0700 (MST)
From:      Terry Lambert <terry@lambert.org>
To:        Andrew.Gordon@net-tel.co.uk
Cc:        freebsd-scsi@FreeBSD.org, j@uriah.heep.sax.de, freebsd-hackers@FreeBSD.org
Subject:   Re: Re(2): SCSI hostadapter
Message-ID:  <199605272126.OAA09109@phaeton.artisoft.com>
In-Reply-To: <"1443-960526225554-A900*/G=Andrew/S=Gordon/O=NET-TEL Computer from "Andrew.Gordon@net-tel.co.uk" 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
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.



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