[KLUG Hardware] Re: SCSI card recommendation

[Bryan J. Smith]

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On Mon, 2002-11-04 at 23:29, John Koenig wrote:
> I was using one of these 2940UW with multiple OSes... one Linux=20
> distro essentially revolted when all three ports were in use. I=20
> glanced at the adaptec manual but did not explicitly see this spelled=20
> out. COulda missed it... I plan to check again when I return to that=20
> project...

Adaptec makes various, custom OEM variants in-house, because they refuse
to license to 3rd parties or release technical specifications.  As such,
those variants don't work with standard Linux drivers.  I also find
Adaptec will package overstocked/under-ordered variants in retail boxes
as well.

The result is that unless you use the driver that comes with the board,
you're probably going to have issues.  Since Linux is _not_ a supported
OS (non-RAID, and only limited for RAID), drivers are not bundled, so
issues result with kernel drivers.

RedHat regularly changes AIC7xxx drivers in their kernels, trying to
mix'n match different versions.  But there's just no way to track all
the OEM variants.  It's a problem with Adaptec's retail-focused model,
as with Promise's.

Only vendors that license to 3rd parties and allow OEMs to build their
own products in-house release technical specifications and allow
flexibility right in the firmware design.  That results in the great
majority of drivers that are compatible with the majority of products
out there.

Yeah, I know, seems weird that "giving up control" actually improves
drivers.  But it's largely because the availability of technical specs
results in the community being able to debug and report back issues with
the drivers, resulting in a broad support base of OEM products.  This is
the model that Symbios Logic and HPT use in the SCSI and ATA world's,
respectively.

> but but since you all were talking about it...
> Does this sound right, that only two of the three connectors (68-pin=20
> external, 50-pin internal, 68-pin internal) can be used at the same=20
> time?

A single-channel SCSI bus can only have "two end-points."  The 2940 is a
single-channel SCSI bus controller, so yes.

[ BTW, "auto-termination" just means the host adapter can detect whether
or not _it_itself_ needs to enable/disable termination.  You still need
to terminate the bus at each end -- i.e. the end of the cable needs to
be terminated too!  Some people think "auto-termination" means they
don't need to terminate cables in use -- not! ]

> IIRC, it was SuSE 7.3 that flagged this as misuse of the card.

I gave up on Adaptec years ago after various issues with OEM as well as
retail versions of their products.  No issues with _any_ 10MBps
Fast/Narrow products, but all faster products have given me fits.

Haven't used any newer Ultra160 solution personally though.

--=20
Bryan J. Smith, E.I.            Contact Info:  http://thebs.org
A+/i-Net+/Linux+/Network+/Server+ CCNA CIWA CNA SCSA/SCWSE/SCNA
---------------------------------------------------------------
The more government chooses for you, the less freedom you have.

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