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Date:      Fri, 8 May 1998 11:48:37 -0600 (MDT)
From:      "Justin T. Gibbs" <gibbs@narnia.plutotech.com>
To:        Matthew Jacob <mjacob@feral.com>
Cc:        hardware@FreeBSD.ORG
Subject:   Re: [Target Mode] Was: Ooops - sorry
Message-ID:  <199805081748.LAA15388@narnia.plutotech.com>
In-Reply-To: <199805050528.WAA14939@feral.com>

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>>> I personally don't like Adaptec monopolizing the SCSI chip business.
> 
> No, you misread me. Qlogic has a separate architecture and makes
> their own chips. Orthogonal to NCR/Symbios and Adaptec. I was
> just mentioning it as a possible viable Target mode platform
> as opposed to trying to deduce target mode for Adaptec (or, rather,
> doing the right microengine foo for the undocumented AIC sequencer),

This is one of the large misconceptions about the Adaptec parts.
The parts are documented and anyone on this list can call the
technical documents department and have Adaptec send you the manuals.
What differentiates Adaptec and Symbios from vendors like Qlogic
is that they do not release their firmware in an easy to use binary
module nor do they release the exact interface to their firmware.
All the information you need to write your own firmware is provided.
I should say that they don't release firmware *yet*, as one of
Adaptec's technical marketting people is working to make the Adaptec
HIM (Hardware Interface Module) available for a "free" driver.
Even if this does happen, they will never release source to their
firmware which, for vendors like Pluto, would make a HIM based
driver much less attractive than the current one.  Most of the bugs
I fix or features I add to the aic7xxx driver have a 1 day turn
around time.  We could never get this kind of response from the
vendor.  There are also features that we plan to implement that
would never interest Adaptec (being able to release target DMA
memory mid transfer by using the "bit bucket" feature of the chip
so our cache can be reused more quickly, for instance) that require
firmware level tweaking.

--
Justin

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