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Date: Wed, 21 Aug 1996 21:13:13 +0200 (MET DST)
Message-Id: <199608211913.VAA04328@x14.mi.uni-koeln.de>
From: Stefan Esser <se@zpr.uni-koeln.de>
To: "Michael L. VanLoon -- HeadCandy.com" <michaelv@HeadCandy.com>
Cc: "Rodney W. Grimes" <rgrimes@gndrsh.aac.dev.com>,
        jas@flyingfox.com (Jim Shankland), freebsd-hardware@FreeBSD.ORG
Subject: Re: SCSI again: Asus SC200 vs. Adaptec 2940 
In-Reply-To: <199608210056.RAA10672@MindBender.HeadCandy.com>
References: <199608202303.QAA08500@GndRsh.aac.dev.com>
	<199608210056.RAA10672@MindBender.HeadCandy.com>
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Michael L. VanLoon writes:
 > However, if you enable tagged-command-queuing in the Adaptec driver,
 > the performance increase is *very* substantial, at least in my tests.
 > Since the BusLogic doesn't currently have tagged-command-queuing in
 > the bt driver, it loses this particular point.  (But remember, your
 > drives have to support it correctly, as well -- there are some older
 > SCSI drives out there that don't support, or have buggy support.
 > Hopefully all current drives on the market have decent support for
 > it.)
 > 
 > I don't know if the NCR has tagged-command-queuing support or not.  If
 > it did, I don't think I would trust it (the NCR driver is OK for
 > workstation type stuff, as Justin pointed out, but it is known to be
 > buggier than either the BusLogic or Adaptec drivers).

Hmmm, thanks.

Yes, the NCR driver has Tagged Command Queuing Support since 
its earliest days (for more than one and a half year now).

It was the only controller that enabled it by default, and we
identified a few disk drives that have broken firmware (with 
the HP 3724 and 3725 being the only current generation drives
affected).

 > >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.

Well, that really would help ...
Why did I never receive a single piece of broken hardware to be able 
to reproduce a problem somebody sees with a single disk, tape or CDROM
drive.

This makes me wonder (again), whether I really should spend $1000
on the necessary hardware, and time worth some $10000 or more (if I 
spent it on paid work) just to allow other people to use the latest
53c8xx variants (Ultra-WIDE), who then complain about a NCR driver
bug, whenever some VM system tuning introduces temporal instability :)

Regards, STefan