MMC-4 Media Serial Number proposal

Hiromichi Oribe Oribe at
Thu Sep 18 14:23:00 PDT 2003

* From the T10 Reflector (t10 at, posted by:
* "Hiromichi Oribe" <Oribe at>
I received some emails asking "Isn't the media serial number command
already defined in SPC document?"  So I would like to clarify my

First of all, READ MEDIA SERIAL NUMBER command is already defined in
SPC-3 document.

I don't think there is anything stopping MMC-4 device to use the READ
MEDIA SERIAL NUMBER command; however, I didn't see a way in the MMC-4
spec to tell the host whether the drive is "capable" of reporting the
media serial number of the currently mounted media.

In other word, how would the host know if the device "supports" the
media serial number reporting or not?

My proposal 1 is to provide a way to tell say in the Features that the
drive is capable of reporting the media serial number via READ MEDIA

My proposal 2 is a way to provide a media serial number in the same way
MMC-4 device can provide logical unit serial number in the Feature

I'm not sure if anyone likes proposal 2 since the command is already
defined in SPC-3.  Though a method to report a unit serial number is
already defined in SPC document (VPD page of INQUIRY command), MMC
devices use a different method to report a logical unit serial number
using one of Feature descriptors.  If MMC-4 wants to apply the same rule
for the media serial number, proposal 2 is a way to do it.


Hiromichi Oribe

-----Original Message-----
From: jim [mailto:jwstephens at] 
Sent: Wednesday, September 17, 2003 8:37 PM
To: Hiromichi Oribe; t10 at
Subject: Re: MMC-4 Media Serial Number proposal

If you wish to have a useful serial number, I would allow the following:

a clear text serial number.

an option for a digital signature containing the serialnumber, and a
signature from
the originator of the serial number, such that the resulting string can
be verified
if desired for the veracity of the signature, and comparison to the
clear text
serial number.

Otherwise one would only have to scan a program for the application of
command (which must be public) going to the driver, and substitute in
serial number desired, (such as one which would allow access to data via

other algorithms).

Jim Stephens

(I am not associated with any current T10 member, just an observer of
the list)

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