Re: Diamond Fireport 40 (Sym875)

Re: Diamond Fireport 40 (Sym875)

[D. Lance Robinson]

Geert Uytterhoeven wrote:
>...
> I borrowed a FirePort 40 from a friend for testing.
> 
...
> The Viking was the last drive on the chain. I tried playing with the
> termination jumper (read: what I thought was the termination jumper, left my
> specs somewhere else :-(, but to no avail. I connected a borrowed CD-Writer
> (PLEXTOR CD-R PX-R412C Rev 1.04) with correct termination to the end of the
> chain to make sure it was no termination problem, but that didn't help.
> 
> Then I removed the Viking from the chain, and everything worked fine. Could it
> be that the cable was too long to use FAST-20 transfers with the Viking? It was
> about 75 cm long.
> 

Geert,

You still probably have a termination problem. You say that the CD-R
works fine. This is a narrow device and only terminates the narrow
signals. The best thing is to use a wide active terminator at the end of
the cable.

<>< Lance.

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Re: Diamond Fireport 40 (Sym875)

[Geert Uytterhoeven]

On Wed, 25 Nov 1998, Geert Uytterhoeven wrote:
> On Mon, 23 Nov 1998, I wrote:
> > I'm considering to buy a Diamond Fireport 40 (SYM53C875 based) UW-SCSI host
> > adapter for my CHRP box (Linux/PPC). Are there known problems with this board
> > on non-Intel architectures?
> >
> > Should I go for a SYM U2W-SCSI board instead? I have a Quantum Viking II U2W,
> > which is currently connected to the (slow) onboard MESH Fast SCSI.
> 
> I borrowed a FirePort 40 from a friend for testing.
> 
> I have the following SCSI devices:
> 
>   - QUANTUM VIKING II 4.5WLS Rev 3506 (U2W, with UW68-to-U50 convertor) 
>   - HP HP35480A Rev T503
>   - QUANTUM FIREBALL_TM3200S Rev 300X (the one with tagged queueing bug ;-(
>   - PLEXTOR CD-ROM PX-12TS Rev 1.02
> 
> Originally these were all connected to the on-board MESH Fast-SCSI controller,
> using a narrow cable, termination on the CD-ROM.
> 
> Since I had no wide cable for testing, I always used the Viking with the
> UW68-to-U50 convertor, even on the '875.

Just bought a Dawicontrol DC-2976UW (Sym875 based), and it works fine with the
ncr53c8xx driver under Linux/PPC. This time I connected the Viking II using a
wide cable. Now it flies at 17 MB/s. Connected to the MESH, it did 6 MB/s only.
The '875 also causes less interrupt stress: a simple read benchmark with hdparm
generates only 256 interrupts, compared to approx. 3500 with the MESH. 

The only disadvantage is that I don't have an Open Firmware driver for the
'875, so I can't boot from the disk. I have to keep my Fireball on the MESH.
Well, I'll get a cheap second hand disk for booting, so I can move the Fireball
to the '875, too.

Greetings,

						Geert

--
Geert Uytterhoeven                     Geert.Uytterhoeven@cs.kuleuven.ac.be
Wavelets, Linux/{m68k~Amiga,PPC~CHRP}  http://www.cs.kuleuven.ac.be/~geert/
Department of Computer Science -- Katholieke Universiteit Leuven -- Belgium


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