Date: Tue, 20 Aug 1996 16:03:31 -0700 (PDT) From: "Rodney W. Grimes" <rgrimes@GndRsh.aac.dev.com> To: jas@flyingfox.com (Jim Shankland) Cc: freebsd-hardware@freebsd.org Subject: Re: SCSI again: Asus SC200 vs. Adaptec 2940 Message-ID: <199608202303.QAA08500@GndRsh.aac.dev.com> In-Reply-To: <199608202229.PAA08050@saguaro.flyingfox.com> from Jim Shankland at "Aug 20, 96 03:29:17 pm"
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>
> A follow-up question, that I hope is of general interest: how does
> the SC200 stack up against the Adaptec 2940U? The SC200 is quite a
> bit cheaper; at what point does it make sense to spring for a
> higher-end SCSI host adapter (assuming the 2940U is higher end)?
> Some systems I build are clear candidates for the SC200; on others
> (multiple disks + a DAT drive, e.g.), I'm not so sure.
>
> Thoughts, anyone?
The line between when to switch from a 53C810 (I prefer to refer to
it by that number, as there are others besides the SC-200) to an
AHA2940U is real wide, and kinda grey, but here are some of the
things I use in helping clients decide this issue.
a) How many disk drives are you going to access at the same time
(cocurrency). If this is >= 3 I recommend using the 2940, otherwise
the SC-200 is fine.
b) Is this a SERVER class machine, ie, does it have more than one person
accessing and doing work on it at the same time. If so ignore rule
a) and use a 2940 as the machine will probably grow to have more
disk drives.
c) What other devices are you running. CDROM drives don't effect the
descission much, but a tower of them points you toward the 2940.
DAT drives are a toss up, though I have seen some funnies from the
NCR code lately on a clients machine when doing dumps to DAT and
am currently in the process of swapping out thier controller and
duplicating the problem here for diagnosis.
It boils down to the NCR is great for desktop/side machines with a few
disk drives. The aha2940 is great for server class machines, or very
large single user systems.
I do have to say that I have an order of magnitude more trust in the
aha2940 driver, and on my ability to get a bug fixed when I need it
(Hi Justin! Thanks for the _GREAT_ support!!) by sending the broken
hardware to Justin and giving him some time to work on it.
> Jim Shankland
> Flying Fox Computer Systems, Inc.
--
Rod Grimes rgrimes@gndrsh.aac.dev.com
Accurate Automation Company Reliable computers for FreeBSD
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