P1394 Mail Archive: P1394> Re: 1284 Device ID rules?

P1394 Mail Archive: P1394> Re: 1284 Device ID rules?

P1394> Re: 1284 Device ID rules?

Mon, 9 Aug 1999 00:55:03 EDT

In a message dated 99-07-30 04:32:43 EDT, isoda@cse.canon.co.jp writes:

<<At the last Copenhagen meeting, we agreed that the descriptor that follows
the "LU entry" should conform to the 1284 Device ID rules.

As far as I remember, the above "1284 Device ID rules" did NOT include the
definition of the new keys, "CLASS" and "CLASSINFO", that was introduced as a
result of PnP off cycle meeting at Redmond.>>

That is my recollection, also.

<<I would like to confirm on what we agreed in order to aviod any further

Peter, is my understanding the same as what you proposed?>>

It's hard for me to answer based upon the terse quality of my notes:

* Use 1284 device string;
* Define usage of CLASS key for MFP devices (CLASS=x,y,z where order is
* Define CLASSINFO key for additional information
* Recommend that parallel, USB and 1394 devices all adopt this convention

<<I think any new keys should not be defined without superceding original
IEEE 1284 specification because it already allows to create any key for the
implementations and any new key may conflict with such an implementation
defined keys.>>

I'm not sure I understand your point, but if I do I agree. Because 1284
already permits creation of new keys, we do not need to seek modification of
1284 itself. On the other hand, the best defense against a new key, such as
CLASSINFO, colliding with vendor-dependent keys is to define the new key ASAP
and to publicize it widely.


Peter Johansson

Congruent Software, Inc.
98 Colorado Avenue
Berkeley, CA 94707

(510) 527-3926
(510) 527-3856 FAX