Peter and all,
We agreed on following proposal in Copenhagen meeting.
<<If you have a textual description that follows the “LU entry”
in the Unit Directory,the descriptor should conform to the 1284
DeviceID rules.>>
I suppose that the intention was to use the textual descriptor with
minimal ASCII character set.
Unfortunately, 1284 device ID string could contain special characters
such as VTAB[x'OB'] that is out of minimal ASCII subset defined in the
p1212r.
Furthermore, the 1284 device ID string is preceded by two byte of
binary length and it does not explicitly prohibit the use of the
NULL[x'00'] in the string. Thus, the 1212r's "textual descriptor"
convention that uses combination of the descriptor_length
(quadlet based) and zero padding could not be used in place of
the two byte length (byte based) followed by the sequence of byte.
In order to avoid the disordered use of various descriptor formats for
the Device ID, I would like to propose to explicitly specify the Device
ID descriptor format that uses organization defining descriptor format
as described below.
The Device ID descriptor is optional. The format of the descriptor
shall follow the format described in attached document
(DeviceID.pdf).
If the Device ID descriptor exists, it shall be preceded by "LU
entry" in the unit directory.
Attached file is the format of descriptor for this.
Takashi Isoda
International Standard Development Dept.2
Canon Inc.
E_mail : isoda at cse.canon.co.jp
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