SSC Large Addresses

Paul Entzel Paul.Entzel at
Mon Feb 28 07:07:28 PST 2000

* From the T10 Reflector (t10 at, posted by:
* Paul Entzel <Paul.Entzel at>
> I highly recommend that when you change the READ POSITION command you
> consider adding a Allocation Length field.  I believe the omission of this
> field was an oversight that was compounded when the Long and TCLP bits
> were added in SCSI-3.  Had there been an Allocation Length field, only a
> single bit would have been required for this new format.  For that matter,
> we should probably add a Service Action code.  These seem to be all the
> rage now.  A Service Action code of 0 could indicate legacy mode, where
> the Allocation Length is ignored and the TCLP and Long bits are not.  A
> new Service Action code can be defined to return the Short Format data in
> a Large Address format, subject to the standard rules pertaining to
> Allocation Length.
> -----Original Message-----
> From:	Paul_A_Suhler at
> [SMTP:Paul_A_Suhler at]
> Sent:	Friday, February 18, 2000 11:54 AM
> To:	paul.entzel at; robbyb at;
> Greg_A_Unruh at
> Subject:	SSC Large Addresses
> Guys,
> Thanks for your input on the proposal.  As expected, there was no
> enthusiasm for
> Reads/Writes/Verifies greater than 16 MB, so that's all out.  What I'll
> now do
> is a detailed proposal for LOCATE (16), SPACE (16), and a new data format
> for
> READ POSITION, with a new bit in the CDB to invoke it.  I'll try to post
> it to
> the T10 reflector next week for discussion in Dallas on 3/7/2000.  This
> will go
> into SSC-2.  Some day.
> Paul, Ralph Weber said that there weren't any more 12-byte command
> opcodes.
> There might exist a workaround, but the group had a strong preference for
> 16-byte.  This will be a bit of a hassle for us, too.
> Cheers,
> Paul
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