Name that multi-port SCSI device

George Ericson gericson at mindspring.com
Fri Jun 11 20:22:49 PDT 1999


* From the T10 Reflector (t10 at symbios.com), posted by:
* "George Ericson" <gericson at mindspring.com>
*
Gene,

Not sure about context of first two sentences of your reply.

On your assertion that dual port drives shipped to date have a SCSI device
for each port.
I don't agree.  I believe that your interpretation is a result of lack of
clarity in the documentation.  The SCSI Device ID should be associated
directly with service delivery ports, not the associated initiator or
target. I believe that this has always been the intent.  The documentation
should improved to make this clear.  With that clarification, in all
respects, the devices you refer to behave as a single dual-ported SCSI
device as documented in SAM and in SAM-2 through revision 8.

Your comment with respect to parallel SCSI interconnect channels is also
true for fibre channel interconnects.  (That is, regardless of interconnect
subsystem, a multi-ported SCSI device can not easily determine whether or
not its ports are attached to the same interconnect subsystem or not.)

-----Original Message-----
From: owner-t10 at Symbios.COM [mailto:owner-t10 at Symbios.COM]On Behalf Of
Gene_Milligan at notes.seagate.com
Sent: Wednesday, June 09, 1999 3:19 PM
To: George Ericson
Cc: 'Harlan Andrews'; t10 at Symbios.COM
Subject: RE: Name that multi-port SCSI device


* From the T10 Reflector (t10 at symbios.com), posted by:
* Gene_Milligan at notes.seagate.com
*
No. My issues is with SAM-2. The dual port drives shipped to date have a
SCSI device for each port. In the case of parallel SCSI they may appear on
two different SCSI busses or they may appear on one SCSI bus at two
different addresses. Of course caution needs to be used since the LBAs
available at these two different addresses have the same media. A stop
command to one address also spins down the other address.

Gene


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