MMC4r03 mismatch in PREVENT/ALLOW MEDIUM REMOVAL command

Pat LaVarre p.lavarre at
Mon Sep 13 13:50:50 PDT 2004

* From the T10 Reflector (t10 at, posted by:
* Pat LaVarre <p.lavarre at>
Henry G:

> an eject request via
> START STOP UNIT ... if either
> Persistent Prevent state or the Prevent state is set.
> ...
>  fairly basic area, which affects many
> devices.
> ...
> important to reconcile
> the MMC draft to both shipping products and Mt. Fuji.

Help, why.

Forever I have wondered, if a host cares about this difference in 
design traditions, then why not teach the host to shadow the prevent 
states internally, and let the host give the host the answer that host 
wants, for any device of either tradition.  My own history of pain 
actually does include hosts rejecting a device of one tradition or the 

Seems to me all that should matter is what the eject button of the 
drive does, not what the actual result is for a paradoxically 
self-contradictory host command sequence.

> As always, your consideration and thoughts on these matters is
> appreciated.


Pat LaVarre

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