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Date:      Sat, 12 Jul 1997 15:40:21 -0700
From:      "Jin Guojun[ITG]" <jin@george.lbl.gov>
To:        asami@cs.berkeley.edu, crb@Glue.umd.edu
Cc:        freebsd-hardware@FreeBSD.ORG, freebsd-isp@FreeBSD.ORG, freebsd-scsi@FreeBSD.ORG, gary@tbe.net
Subject:   Re: NCR SCSI controllers
Message-ID:  <199707122240.PAA21522@george.lbl.gov>

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>Also, I don't know how the NCR controllers perform under heavy load as
>I never had more than two disks on them -- the Adaptec generally works
>fine with 14 disks in 10MHz mode or 8 disks in 20MHz mode (cable
>length problem).

I have no problem with NCR at all. Specially under FreeBSD, It does not take
CPU time. Two disks or 14 disks is not the issue for SCSI controllers.
If you can saturate the SCSI bus with two disks (new tech can), then, putting
100 disks (assume ID is allowed), would not make any difference at all.

See Hardware performance guide for Pentium family (new) under
http://www-itg.lbl.gov/ISS/hardware (two years old and it will be updated
soon :-)

> * I do have to admit, however, that I am not getting ultra-wide speeds out
> * of my Tekram even though I have an ultra-wide capable IBM UltraStar 2es
> * but I haven't really looked into it yet to see if this is just a configuratio
>n
> * problem or what.
>
>Our NCR driver doesn't support it yet.  Stefan Esser (se) is working
>on it.  Based on past experience, my guess is that it will start
>working soon because se is working on it. :)

Does some one have tested any ultra-wide SCSI controllers to have at least
more than 20 MB throughput over a single controller with number of ultra-wide
disks? I posted such question a few month ago, and did not hear any respond.
I was wondering no one had it worked at that time.

-Jin




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