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Date:      Wed, 1 Mar 1995 23:00:12 -0800 (PST)
From:      "Rodney W. Grimes" <rgrimes@gndrsh.aac.dev.com>
To:        olsenc@ichips.intel.com
Cc:        questions@FreeBSD.org, hardware@FreeBSD.org
Subject:   Re: Questions about support for NCR 53c825????
Message-ID:  <199503020700.XAA13606@gndrsh.aac.dev.com>
In-Reply-To: <9503020625.AA30072@dtt030.intel.com> from "olsenc@ichips.intel.com" at Mar 1, 95 10:25:31 pm

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> 
> 
> Hello:
> 
> I posted on the net and got no response on this.  Is there
> support, or plans for support, for the NCR fast-wide SCSI
> II chipset?
> 
> I've read the FAQ, and I saw the generic 810 support.

There is already support in the driver for the 53C825 chip:
hookturn# dmesg 
FreeBSD 2.1.0-Development #0: Sun Feb 26 13:00:35 PST 1995
    rgrimes@hookturn.aac.dev.com:/usr/src/sys/compile/HOOKTURN
...
ncr0 <ncr 53c825 wide scsi> int a irq 11 on pci0:17
        reg20: virtual=0xf28fc000 physical=0xf0000000

I currently don't have any wide devices so I can't actually say
that it works with wide devices, but it works just fine with fast
scsi-ii devices.

I am also running the same controller under 2.0R without problems.

> Would fast-wide really be necessary?

If you are using very fast disk drives wide can be a payoff.  Note
that drives like the Quantum Empire 2100S are capabile of 5MB/sec
transfer rates, so 2 of them on a fast scsi-ii bus pretty much
kill the scsi bus.  And these are only 5400 RPM drives, now image
what happens if you are running a couple of Quantum Grand Prix 4301
7200 RPM drives, these should do close to 6.7MB/sec.  For that you
would really want to go with a wide controller and wide drives.

> Opinions would be very appreciated.

If you want top performance the premium for fast wide scsi disks can
bring some real benifits.  For a single user system it is probably
not worth it, but for a server or multiuser system it can be money
very well spent.

> -Clint


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



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