P1394> Re: 1284 Device ID rules?

P1394> Re: 1284 Device ID rules?

PJohansson at aol.com PJohansson at aol.com
Mon Aug 9 00:55:03 EDT 1999


In a message dated 99-07-30 04:32:43 EDT, isoda at 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 
confusions.

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 
irrelevant)
* 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.

Regards,

Peter Johansson

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

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

pjohansson at aol.com



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