Device Tray Open!

David Burg dburg at nero.com
Mon Oct 24 00:21:16 PDT 2005


* From the T10 Reflector (t10 at t10.org), posted by:
* "David Burg" <dburg at nero.com>
*
Hi Bill,

I saw multiple engineers new to MMC writing code relying on ASCQ = 2 (and
ASCQ = 1 for closed). I think we should accordingly improve the
specification to avoid this error to be repeated.

> The drive is only required to return the media event block when a media
event has occurred.  So, the Tray/Door Open status can only be seen when a
media event is reported.

Surprisingly, the device behavior I am used to is that the media event block
*is* returned when no media event occurred, but that "Media Event" field
equals 0h (no event) - then the tray open most of the time reports actually
the door status (some devices are bugged and return always 0). I checked
this right now with my laptop drive. I am not sure I met any device so far
which does *not* return the no change media event block. Are all these
devices not conforming to MMC? :-?

If as you say media event is sometimes available but not a reliable solution
(that is, not always available), again this is leading software engineers to
write bogus code and the specification should be improved to avoid it.

Best regards,

David.

-----Original Message-----
From: Bill McFerrin [mailto:billmc at tstar.net] 
Sent: Sunday, October 23, 2005 5:58 AM
To: 'David Burg'; t10 at t10.org
Subject: RE: Device Tray Open!

Hi David,
Two of the three methods are mandatory.  The specific error code is not
mandatory.  Most people report 02/3A/00 when there is no media present.
ASCQ = 2 (tray open) is rare.

The drive is only required to return the media event block when a media
event has occurred.  So, the Tray/Door Open status can only be seen when a
media event is reported.

Mechanism Status gives static information and is useful at any time.

I think that both are useful, but if you wish to drop one, then it should be
the bit in the media event block.

Bill

-----Original Message-----
From: owner-t10 at t10.org [mailto:owner-t10 at t10.org] On Behalf Of David Burg
Sent: Friday, 21 October, 2005 2:08 AM
To: billmc at tstar.net; t10 at t10.org
Subject: RE: Device Tray Open!

* From the T10 Reflector (t10 at t10.org), posted by:
* "David Burg" <dburg at nero.com>
*
Dear Bill, Dear MMC members,

Do we have a good reason to preserve the duplication of MECHANISM STATUS
command response "Door Open" bit and "Get Event/Status Notification" CDB
with a Notification Class Request of "Media" Door or Tray Open bit (bit 0 of
byte 5) in MMC5?

If we don't, maybe we can make one of the two obsolete and simplify both
host and logical unit implementation. Having 3 different reports of the door
status (sense code, mechanism status, GESN) isn't good.

Best regards,

David Burg

----------------------------------------------------------------
David Burg
Senior Engineer
Standardization and Research

Nero AG               phone: +49 (0)7248 928 327
Im Stoeckmaedle 18    fax:   +49 (0)7248 928 299
76307 Karlsbad        email: dburg at nero.com
Germany               http://www.nero.com
----------------------------------------------------------------



-----Original Message-----
From: owner-t10 at t10.org [mailto:owner-t10 at t10.org] On Behalf Of Bill
McFerrin
Sent: Thursday, October 20, 2005 2:13 PM
To: t10 at t10.org
Subject: RE: Device Tray Open!

* From the T10 Reflector (t10 at t10.org), posted by:
* "Bill McFerrin" <billmc at tstar.net>
*
Wasim,
Try the MECHANISM STATUS command.  Its response has a "Door Open" bit that
should report the status you want.

Bill McFerrin

-----Original Message-----
From: owner-t10 at t10.org [mailto:owner-t10 at t10.org] On Behalf Of Wasim Sabir
Sent: Wednesday, 19 October, 2005 3:17 PM
To: t10 at t10.org
Subject: Device Tray Open!

* From the T10 Reflector (t10 at t10.org), posted by:
* Wasim Sabir <wasim.sabir at gmail.com>
*
Dear All,

Is there any way I could check whether a device tray is open? I have
tried ReadDiscInformation over an open try device and hoped that it
would return me error "MEDIUM NOT PRESENT - TRAY OPEN" but it always
return "MEDIUM NOT PRESENT".

--
With kind regards,

Wasim Sabir
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