MMC / Mt Fuji: Obsolete operation request/report codes to be marked so and clarification request for AddChange code

David Burg daviburg at
Mon Aug 7 16:17:12 PDT 2006

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In previous Mt Fuji specification, e.g. Fuji3v100, multiple operation
request/report codes were defined beside 00h and 01h. Namely this was
"2h AddChange The Feature list may have added Current Features (no
Features became non-Current)
3h Reset The Logical Unit has been reset.
4h Firmware Changed The Logical Unit's microcode may have changed.
5h Inquiry change The Logical Unit's identification information may have
In current Mt Fuji (6) and MMC (5) specification these values are
reserved as if for future use:
"2h - FFFFh Reserved -"
I believe that instead 2h to 5h need to be marked obsolete to avoid that
these values are eventually redefined for a new purpose.
Also, Microsoft would need clarification about the meaning and scope of
occurrence (aka condition) of the AddChange. We have observed this in
existing drives (during packet writing) and we currently interpret this
value in our storage driver as the media behavior may have change thus
the file system volume should be checked for change before continuing to
write. Notice that verifying that the volume hasn't changed is an
expensive check when actually the media hasn't changed: the file system
needs to go through all the directory entries to ensure they are still
there / intact. Thus we are wondering what are the conditions which
caused an AddChange to be triggered and whether we should continue to
perform this expensive verification or we can safely continue our reads
and writes to this media.
Please clarify when is AddChange report.
Why was this AddChange removed from the specifications eventually?
This issue is affecting work on the life file system of Vista RTM, thus
we would appreciate if the committee could have a quick turnaround
studying this matter.
Best regards,
David Burg
Research Software Engineering Lead
Tel.: +1 425 707 8769

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