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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