Name that multi-port SCSI device
cbinford at lsil.com
Fri Jun 11 13:58:08 PDT 1999
* From the T10 Reflector (t10 at symbios.com), posted by:
* "Binford, Charles" <charles.binford at lsil.com>
Gene, you say "dual port drives shipped to date have a SCSI device for each
port." What is difference between the words 'Device' and 'Target'? How
significant of a difference is there between the phrases
- "a SCSI device for each port" and
- "a SCSI target for each port"
To come at this from another direction consider the reset implications.
I've always assumed the SCSI-2 term 'Bus Device Reset' mapped directly to
the SCSI-3 term 'Target Reset'.
What happens if I issue a Target Reset to your drive via the loop A port?
A) all I/Os get canceled (regardless of which port they were delivered on)
B) only I/Os delivered via loop A port get canceled
I would say the correct answer is A) for Target Reset. Yet if I asked the
same question about 'Bus Device Reset' I get confused. Using your phrase "a
SCSI device for each port" would mean answer B). However my equating BDR
and Target Reset would say the answer should continue to be A).
LSI Logic Storage Systems
> -----Original Message-----
> From: Gene_Milligan at notes.seagate.com
> [SMTP:Gene_Milligan at notes.seagate.com]
> Sent: Wednesday, June 09, 1999 2:19 PM
> To: George Ericson
> Cc: 'Harlan Andrews'; t10 at aztec.co.lsil.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.
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