SUMMARY: Sun X6541A, E250, and the AIT Library of DOOM!

From: Dave Belfer-Shevett <>
Date: Sat May 17 2003 - 09:22:27 EDT
My original question....

On Fri, 16 May 2003, Dave Belfer-Shevett wrote:
> I have a Sun E250 running Solaris 2.8 whos sole task is to run backups to
> a pair of Overland LibraryPro's with AIT-3's in them.
> Initially we were having tons of SCSI timeout errors running dumps to the
> AIT drives, so I decided to purchase a 'known' working card, the Sun
> dual-channel differential SCSI controller, an X6541A.


Many folks have brought me into the 2000's and pointed out that SCSI has
moved beyond SCSI-1 and SCSI-2, wide and narrow.

The Overland uses LVD/SE SCSI, and the X6541A controller is a High Voltage
Differential SCSI controller (frequently simply called Differential).
Even though the controllers look identical, and the cables connect up
fine, there's no way they'll work together.

The solution is to replace the X6541A controller with an LVD SCSI
controller, such as an X6540A, which is a dual LVD Single Ended SCSI
controller (and incidentally is half the price of the X6541A.  :)

Good supplier, btw... (any opinions on which of these to use?  Or are they
basically identical?)

Thanks to:

From: "Haywood, Steven" <>
From: Adam and Christine Levin <>
From: Drew Skinner <>
From: Tony Walsh <Tony.Walsh@Sun.COM>
From: Paul Boven <>
From: Michael Hyman <>

Choice tidbits:

Seems there's two options on the overland - HVD or LVD/SE

From: "Haywood, Steven" <>

Take a look on the back of the tape libraries, at the scsi symbol
Either it's a diamond, or a "3d" diamond (ie, has a shadow).
If it's a single diamond it's LVD/SE, double diamond is HVD.
The connectors are identical ( :((( )
From: Jay Lessert <>
> dual-channel differential SCSI controller, an X6541A.

That is an HVD (high voltage differential) Ultra Wide Differential card.
Are you *sure* your changer and drives are HVD?

I'm not sure Sony makes an AIT drive with HVD, I think they are all LVD
(Ultra2).  Look next to the connectors on your controller and the
changer.  You'll see a diamond-shaped symbol.  See:

If I'm right, your controller has the HVD symbol and the changer has one
of the two LVD symbols.  If so, this combination will not work.  You
probably haven't destroyed anything (SCSI interface electronics are pretty
rugged), but you need to change the controller.

Dave Belfer-Shevett\ KB1FWR \    >--------`------------------------------------  / "If you talk to God, you are praying. If God \
------------------<    talks to you, you have schizophrenia." -    |
                  |                  Thomas Szasz                  |
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Received on Sat May 17 09:22:23 2003

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