How to tell differential scsi drives and cards apart

[Rich Alderson]

From: jim s
Sent: Saturday, January 10, 2009 8:54 PM

> The HVD bus is designed such that if you plug it into a SE bus it will
> go into reset and go passive.  There is a signal DIFFSNS on the HVD that
> will disable the bus.  Not good, but better than nothing if you mess up
> and plug them together.

I don't think so.  The XKL Toad-1 was designed with FASTWIDE differential SCSI,
and any single-ended peripheral that got connected accidentally was guaranteed
to lose the magic smoke and go off to live with <insert $DEITY here>.  We were
in complete accordance with the SCSI specs.

 [ Regarding Paralan: ]

> The link below points to a company who makes the converters.  Sometimes
> they are available on Ebay, and there are some repackaged by Compaq and
> HP that show up.  They make both the 50 an 68 pin versions.  I doubt
> they will work over 5m/sec with HVD involved, however.

They work at 10MB/second on the Toad.  We had to include one in the system
because HP DAT drives and Quantum DLT drives were unavailable with differential
interfaces.

I purchased a Paralan HVD/LVD converter here in order to attach a SCSI JBoD
array to the Toad, in anticipation of hosting a lot of data.

Rich Alderson
Server Engineer, PDPplanet Project
Vulcan, Inc.
505 5th Avenue S, Suite 900
Seattle, WA 98104

mailto:RichA at vulcan.com
(206) 342-2239
(206) 465-2916 cell