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Date:      Thu, 26 Feb 1998 23:01:05 -0800 (PST)
From:      Tom <tom@sdf.com>
To:        Nate Williams <nate@mt.sri.com>
Cc:        Johnathan Raymond Sconiers II <john@Mcs.Net>, hackers@FreeBSD.ORG
Subject:   Re: do you support 
Message-ID:  <Pine.BSF.3.95q.980226224412.19894E-100000@misery.sdf.com>
In-Reply-To: <199802270508.WAA01402@mt.sri.com>

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On Thu, 26 Feb 1998, Nate Williams wrote:

> >   Programming info is available for Adaptec cards, just like the NCR
> > cards.  Perhaps maybe 3 years ago that was case, but not for a long time.
> > The Adaptec cards do more things on-board so the driver is more complex.
> 
> My NCR board performs within 10% (sometimes faster in certain

  Possibly.  The transaction overhead of the ahc is much lower than
the ncr driver.  The only way to see this is to use lots of simultaneous
io to lots of drives.  I'm not aware of any benchmark software that lets
me test this easily.  bonnie isn't much good for this.

  Also, if you want performance, skip both Adaptec and NCR and get a DPT
PM334UW instead.  I having _great_ success with a DPT PM334UW on a
FreeBSD 2.2-stable system.

> benchmarks) of the Adaptec driver, and hasn't been broken in 3 years.
> Tell me that the stability/usability of not having it broken *ever* in 3
> years isn't worth it.

  I'm not to argue that, but this problem does not exist as result of not
having programming specs.  The Adaptec specs are available.

  Also, the ahc driver support Ultra months before the ncr driver.

> >   Also, the existing ahc driver is not being maintained anymore.
> 
> The NCR has rarely been touched as well.

  Don't confuse maintenance with "touching".  FreeBSD has many examples of
code that is rotting, because of lack of attention.  Be glad that someone
is maintaining the ncr driver once and while.

> > It has known bugs that no one will fix, because the SCSI people are
> > looking ahead to CAM.
> 
> Yet another good reason not to use the Adaptec boards.  Looking to the
> future is all well and good, but it leaves a bitter taste in my mouth to
> get stuck with brokeness all in the name of progress, especially when
> other options exist.

  Yes, it is bad thing, but not because you get "stuck with brokeness",
but because the brokeness existed at all.  The ahc driver doesn't have to
be "bad".

  Both existing ahc and ncr users are going to be stuck anyhow.  The
existing SCSI code is dead.  Anything new will be CAM.  This is hardest on
new SCSI drivers, because they won't be brought in until CAM is brought
in.  There is a perfectly good DPT driver in the wings waiting for this,
plus I believe a new AdvanSys driver too.

> Nate

Tom


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