[T10] ZBC-2 complications for obsoleting 6 byte MODE SELECT / MODE SENSE commands

Gerry Houlder gerry.houlder at seagate.com
Thu Aug 4 09:52:58 PDT 2022


I have observed that ZBC-2 rev. 13 references SPC-6. If my proposal to obsolete the 6 byte MODE SELECT and MODE SENSE commands is accepted, there are 4 instances of MODE SELECT or MODE SENSE that do not include a number of bytes (e.g., (6) ) after them. These would have to be changed to add (10) after them. ZBC-2 is in an advanced state of trying to be published (I think new proposals are not being accepted at this time?). How to we resolve this problem? i think the ZBC-2 changes must be included in my proposal to obsolete the 6 byte commands.

A much simpler approach is to allow MODE SELECT and MODE SENSE without any number of bytes on it to remain. Per existing rules, that reference would still apply to a 10 byte version of those commands and greatly simplify the fallout changes to other standards. I would like to start a reflector discussion on that approach in hopes of coming to a conclusion for that option at the September T10 meeting

SAT-6 will have a much larger set of changes to include SPC-6, but since that is just in the formative stages that can be addressed by a separate proposal.

SPL-5 rev. 15 only references SPC-5, so that would not be affected. A future SPL-6 would have 45 instances of MODE SELECT or MODE SENSE that would need a (10) added.

SAM-6 only references SPC-5 so that would not be affected. A future SAM would have one instance of MODE SELECT that needs to change to MODE SELECT (10).

SAS 4.1 has no instances of MODE SELECT or MODE SENSE so is not affected and future revisions should also not be affected.

I haven't analyzed the other standards, but they currently reference SPC-5 have would have no immediate changes.


Seagate Internal
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