MMC Multi-session Mode Read_TOC

BLACKSON Jim blackson at
Wed Jan 21 02:49:34 PST 2004

* From the T10 Reflector (t10 at, posted by:
* BLACKSON Jim <blackson at>
I wonder if some MMC experts would kindly help me out.

The USB-IF DWG Mass Storage committee is putting together a specification to
boot a PC from USB mass storage devices.  I imagine such devices would
include MMC devices such as CDs and DVDs.

To boot from a CD, I am told that a boot BIOS needs to find out if a CD has
multiple sessions.  In SFF2080r26, I understand that a BIOS issues a 0x43
Read_TOC command with byte 2 set to zero and byte 9 bits 7-6 set to 01b
("multi-session mode"), to which a device sends back a packet of data that
contains the first and last session numbers.

Do (all) MMC devices support this SFF2080-style Read_TOC, or is there the
"MMC way"?
And what does that "MMC way" 0x43 Read_TOC command look like?

Best regards,
Jim Blackson
Y-E Data, Inc.

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