Revision: SET CAPACITY Command Does Not Exist

Paul_A_Suhler at Paul_A_Suhler at
Mon Feb 21 13:19:12 PST 2000

* From the T10 Reflector (t10 at, posted by:
* Paul_A_Suhler at
(Please disregard my previous message about SET CAPACITY; the new opcode being
considered is 0Bh (not 92h), which will NOT require a 16-byte CDB.)

The SET CAPACITY command, opcode 1Fh, was removed from draft 14 of SSC over a
year ago.  There is one technical public review comment against SSC to reinstate
it.  I've been asked to prepare the response to this comment and would like
input from the community, both drive vendors and application vendors.

1.  Have you implemented or do you plan to implement SET CAPACITY?

2.  What would be the impact of changing the opcode from 1Fh to 0Bh?
(Ralph Weber has requested this because 1Fh is the only 6-byte opcode that is
unused by any device, while 0Bh *is* used for disks and printers.  Totally
unused opcodes should be conserved for SPC commands.)

3.  Could you use MODE SELECT to achieve the same functionality if SET CAPACITY
were not available?

Please respond either directly to me or to the reflector.


Paul Suhler
Seagate Removable Storage Systems
Costa Mesa, California

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