AACS & number of AGID available

Henry Gabryjelski Henry.Gabryjelski at microsoft.com
Tue Nov 22 11:40:52 PST 2005


* From the T10 Reflector (t10 at t10.org), posted by:
* "Henry Gabryjelski" <Henry.Gabryjelski at microsoft.com>
*

Dear all,

Further investigation into the specifications and long discussions have
shown that the additional AGID for read/write media will not be
necessary.  So, please accept my withdrawal of the below request to
require a minimum of 2 AGIDs when AACS BNG bit is set to one.

Sincerely,

Henry Gabryjelski

-----Original Message-----
From: owner-mtfuji5 at avc-pioneer.com
[mailto:owner-mtfuji5 at avc-pioneer.com] On Behalf Of Henry Gabryjelski
Sent: Tuesday, November 08, 2005 3:48 PM
To: mtfuji5 at avc-pioneer.com; t10 at t10.org
Subject: AACS & number of AGID available


Dear all,

A number of months ago, some discussion around the minimum number of
AGIDs required to implement AACS was asked at the Mt. Fuji meeting.
Software companies felt uncomfortable with the restriction to a single
AGID, but were not able to show a need for more than one AGID for the
read-only case.  At the time, the AACS specification (as shown in Fuji)
was not final.

The recent updates of the Fuji document have enabled a more thorough
analysis of the requirements.  I have still found no need to increase
the AGID count for _READ_ONLY_ media.  Because of the short lifetime of
the AGID for AACS (only valid for a single read of information),
read-only media is likely OK to have only one AGID.

However, when creating a device which supports updating the nonce values
(BNG=1 in the AACS feature), I think a minimum of two AGIDs may be
required in some cases.

Currently, the specification does not require any number of AGIDs to be
supported for AACS.  However, I would like to request the following
modification be made to the AACS feature (010Dh) in GET_CONFIGURATION:

Old Text:

The Number of AGIDs field indicates the maximum number of AGIDs that the
logical unit supports concurrently.

New Text:

The Number of AGIDs field indicates the maximum number of AGIDs that the
logical unit supports concurrently.  If BNG is set to one, the device
shall support a minimum of two concurrent AGIDs.

Thank you,

Henry Gabryjelski
Microsoft Corporation
*
* For T10 Reflector information, send a message with
* 'info t10' (no quotes) in the message body to majordomo at t10.org





More information about the T10 mailing list