During the PMP conference call last Friday (Oct 18), I brought up
the question of how a client can accurately determine the precise
printer model for an agent of the Printer MIB.
I explained (as did David Kellerman) that we host-based printing
software developers needs a concise, accurate and (above all)
standard way of determining exactly which model of printer is on
the other end of the wire. This is necessary for driver-level
software to know how to access the various printing features on
a particular model, similar in concept to the ".ppd" files used
by Adobe for their PostScript drivers, etc.
I went on to say that Underscore has been unable to locate any
relevant MIB object (either in the Printer MIB or other MIB) that
can give us that information.
Harry Lewis was kind enough to point out that the hrDeviceID object
in the Host Resources (HR) MIB does indeed exist to provide exactly
that kind of information.
Those participants in the con-call who seemed to know about such
things (including myself!) believed that Harry must have been mistaken,
that the MIB object to which he referred was actually used to identify
the TYPE of device, and not the (vendor-specific) model information.
Believing Harry might not have been accurate in his description of the
HR MIB object, I went on to suggest that perhaps the PWG could add such
a critical MIB object to the new draft, as part of the prtGeneral Group.
Well, upon further investigation, Harry was 110% correct. (Sorry, Harry!)
The hrDeviceID object is *exactly* what we've been looking for!
That's the good news...
Unfortunately, the bad news is that it's not clear how many other printer
vendors know about this critical MIB object.
Here at Underscore we have 3 models of printers that currently support
the Printer MIB (RFC-1759). Of those 3 models, only the IBM printer
has a valid (ie, useful) value for the hrDeviceID...the other two printers
return a NULL value for the hrDeviceID MIB object.
Therefore, while it's great that we won't have to add a new MIB object
to the prtGeneral Group, it is imperative that all Printer MIB implementors
accurately implement the hrDeviceID object for all of us software vendors.
I'd like to ask for a "show of hands" of all printer vendors (and any
others that implement the hrDeviceID MIB object) as to whether a non-null
value is returned for their products.
Thanks in advance for your responses. This is a very critical issue for
all printer driver developers, so please respond as soon as possible.
Questions/comments/complaints/flames/libel/etc are most welcome. Let's
open a discussion on this topic, particularly if not everyone understands
the importance of the hrDeviceID MIB object.
...jay
PS: Following on the heels of this topic should be a discussion as to
how printer vendors can publish their printer model OID values in
a general and public manner so that developers can stay abreast of
the set of defined values. To my knowledge, no such general repository
exists for this purpose (please correct me if I'm wrong here!).
If no such Internet-accessible repository exists, then Underscore
would be willing to maintain such a repository as part of the PWG
ftp site. Let's get this going as soon as possible!
PPS: Again, sorry, Harry! ;-)
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-- JK Martin | Email: jkm at underscore.com --
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