SSC issues: Clarifications needed for Medium Partition Page (11h)

Jan F. Rebalski Janek_Rebalski at
Fri Feb 6 14:24:42 PST 1998

* From the T10 (formerly SCSI) Reflector (t10 at, posted by:
* "Jan F. Rebalski"<Janek_Rebalski at>

It appears to me that the section of X3T10/997D rev.11 omits
adequate clarification of the following scenarios:

   What happens (or should happen) when none of the FDP, SDP, IDP bits are

   What happens when the POFM bit is set when the CLEAR and/or ADDP bits
   are set? POFM is explained only in relation to FDP, SDP, and IDP bits.

   Why is the combination of (POFM = 0 and [FDP | SDP | IDP] = 1) legal at
   the BOP only? How does this relate to any possible combination of the
   CLEAR and ADDP bits?

   The scenario of (CLEAR = 1 and ADDP = 0) is defined specifically for the
   situation when one of the FDP, SDP, and IDP bits is set. None of the
   other possible combinations of CLEAR and ADDP bits mention the relevance
   of the FDP, SDP, and IDP bits.

All in all, the relationship among FDP, SDP, IDP, POFM, CLEAR, and ADDP
bits appears to be rather tenuous, if not somewhat incomplete. There are
additional functionalities hinted at in reference to these bits when their
interplay with partition size descriptors and the FORMAT MEDIUM command is
taken into account. If this section remains the way it is, I think that it
will cause much confusion in the potential implementations of
multi-partitioning in tape devices. At this point, I don't think it is
possible to implement a robust validation logic for Page 11h, and
consequently we may see a multitude of compatibility problems.

A relationship table listing these bits is probably called for.


Jan F. Rebalski
Advanced Storage Development, CCPG
Sony Electronics, Inc.
3300 Zanker Road, M/S SJ3B2
San Jose, CA 95134-1940
Phone:  408-955-4535
Fax:    408-955-5066
mailto:Janek_Rebalski at

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