Thin device provisioning

Matthew Wilcox matthew at
Fri Aug 8 06:15:11 PDT 2008

* From the T10 Reflector (t10 at, posted by:
* Matthew Wilcox <matthew at>
Good morning Fred,
I've been looking at your 08-149r0.pdf with a view to using the 'PUNCH'
command to implement the Linux 'DISCARD' command.  It's a little
over-specified for what we need and this causes the implementation to
be a little more complex than I would like.  The excess capability is
the ability to do multiple punches in a single command.  Do you really
need to be able to add/remove lots of ranges atomically, or could you
use a command specified like this:
0	0x9F
1	service action
2-9	LBA
10-13	length
14	reserved
15	control
and send one command for each range?
Apologies if this has already been covered in a T10 discussion; I'm not
a member and though I've searched the archives, I may have missed a
Intel are signing my paycheques ... these opinions are still mine
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours.  We can't possibly take such
a retrograde step."
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