Likely editorial error inducing confusion in MMC-4 and MMC-5, DVD+R/RW/DL Profiles

Bill McFerrin billmc at tstar.net
Thu Aug 4 21:15:11 PDT 2005


* From the T10 Reflector (t10 at t10.org), posted by:
* "Bill McFerrin" <billmc at tstar.net>
*
Dear David et al,
A Profile is simply a notation by the drive that a certain list of features
is present.  If a profile is current, then some critical number of the
features in the profile's list are current.  Profiles add no technical
value, but obviously profiles do add confusion.

It is possible to build a drive that supports exactly one media type.  The
profile lists what is considered to be the  minimum list of features needed
to "be" that type of drive.  Consequently, a profile is a marketing
judgement.  Some applications people have decided that profiles are useless,
so their software ignores profiles and trusts only features.

Beyond that, I need to fix the wording that describes the READ-TIME
STREAMING FEATURE.  It is correct, but it is also confusing.

I think that the WRITE bit in each of the DVD+R, DVD+RW, DL DVD+R, and DL
DVD+RW features makes write capability very clear.

Regards,
Bill McFerrin

-----Original Message-----
From: owner-t10 at t10.org [mailto:owner-t10 at t10.org]On Behalf Of David
Burg
Sent: Thursday, 04 August, 2005 10:22 AM
To: 'Bill McFerrin'; t10 at t10.org
Cc: James_Lo at Dell.com
Subject: Likely editorial error inducing confusion in MMC-4 and MMC-5,
DVD+R/RW/DL Profiles


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

James Lo from Dell brought to my attention that MMC description of
DVD+R/RW/DL Profiles "contain the requirement to support Read/Write
Streaming which as you know ROM drives cannot support".

I think the DVD+Rxxx Profiles wording induces to a confusion. The DVD-ROM
Profile contains also the Feature 107h (Real-Time Streaming), but a clear
description ("Ability to read using Initiator requested performance
parameters") while the description for the same feature in the DVD+Rxxx
Profiles ("Ability to read and write using Initiator requested performance
parameters") induces the confusion that it looks like a DVD+Rxxx capable ROM
drive would need to support (real-time) writing. I think this is really
un-intentional because you see for write-related features notes such as
"1This feature is mandatory only when the Write bit of the DVD+RW Feature is
set to one."

Reporting DVD+R/RW/DL Profiles as current by ROM drives when matching media
is inserted is desirable to best identify the media. Reporting the Features
even when no media is inserted is required to report the capability of the
device (so for instance diagnostic tools such as Nero InfoTool can provide
accurate information). Actually Profiles and Features go hand-in-hand and
should be present together, shouldn't they?

I propose to change the wording from "Ability to read and write using
Initiator requested performance parameters" to "Ability to read and
optionally write2 using Initiator requested performance parameters", with a
note "2 Real-Time Streaming Write is supported when the Write bit of the
DVD+Rxxx Feature is set to one."

Btw, is there any ISV which assimilated erroneously the presence of
DVD+R/RW/DL Profiles to the capability to write these media due to the above
reported confusion? (Nero products do not, but we wonder about other ISVs.)

Best regards,

David Burg

----------------------------------------------------------------
David Burg
Software Development

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