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Date:      Mon, 22 Feb 1999 00:20:46 +0100 (MET)
From:      Jean-Marc Zucconi <jmz@FreeBSD.ORG>
To:        ken@plutotech.com
Cc:        scsi@FreeBSD.ORG
Subject:   Re: LVD transfer rate
Message-ID:  <199902212320.AAA23952@qix>
In-Reply-To: <199902212301.QAA21624@panzer.plutotech.com> (ken@plutotech.com)

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>>>>> Kenneth D Merry writes:

 >> I have a jumper labelled `SE mode', and this jumper is ON, however the
 >> drive does not work if I remove the jumper: the drive appears in the
 >> SCSIselect utility, but it does not reports its capacity, and trying
 >> to format fails (Not ready, asc/ascq= 40/80). 

 > That jumper forces it into Single Ended mode.

OK. this explain why I only get 40MB/s

 > What kind of cable do you have?  LVD drives don't have internal
 > terminators.  You need an LVD cable (one of the "twisty" 68-pin cables)
 > with a terminator block on the end.

I have the right cable, the terminator block is currently removed, but
during my tests without the SE jumper, I got similar results with and
without the terminator block.

 >> > I seriously doubt this is your problem, but I've got a machine at work with
 >> > two 18G Seagate Cheetah II's on a Super Micro motherboard with an onboard
 >> > 7890.  The problem is that the drives are SCA, and the SCA to 68-pin
 >> > converters we put on them apparantly inhibit LVD.  So they only run at
 >> > 20MHz instead of 40MHz.
 >> 
 >> No - connectors and cables are standard (80pins)

 > You have SCA disks?  Is the cable terminated?

The disk has a SCA connector. The cable is not terminated (the drive
is currently at the very end of the cable).

Jean-Marc


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