[MFD] RE: "Support Levels" for the SM2.0/PWG:PJT

[MFD] RE: "Support Levels" for the SM2.0/PWG:PJT

Zehler, Peter Peter.Zehler at xerox.com
Thu Feb 14 11:52:45 UTC 2013


Glen,

The semantic model, and IPP, has never had the position of "requiring all Applications and Print Clients in the various environments to support the complete set of PWG: PJT objects, elements, attributes and values".  Anything a Print Client does not understand can be silently dropped on the floor.  (The model does define some mandatory elements.  Those are 22 Printer Status and Description elements and 9 Job Status and Description elements.  Most of those deal with charsets, languages, state and identifying information.)  There is no requirement that Printers or Clients must even support a PJT.  If a PJT is supported only 1 element must be supported (i.e., JobName).  If a Print Document Ticket is supported then only 2 elements must be supported (i.e., DocumentFormatSupplied  and LastDocument).

There is no requirement that "Print Client must support all PWG:PJT objects, elements, attributes and values that any Print Service could potentially provide as a capability".  For that matter there is no requirement that the Print Service must support all the PWG:PJT.  The Client can be coded to only understand a small subset of the model, the entire model, a superset of the model or even a subset with extensions.  When the Client encounters an element it does not understand it silently ignores it.  The end user will only see the intersection of the set of elements supported by the Client and those implemented by the Printer.

Then again maybe I don't understand the problem you are trying to solve.

Peter Zehler

Xerox Research Center Webster
Email: Peter.Zehler at Xerox.com<mailto:Peter.Zehler at Xerox.com>
Voice: (585) 265-8755
FAX: (585) 265-7441
US Mail: Peter Zehler
Xerox Corp.
800 Phillips Rd.
M/S 128-25E
Webster NY, 14580-9701


From: cloud-bounces at pwg.org [mailto:cloud-bounces at pwg.org] On Behalf Of Petrie, Glen
Sent: Wednesday, February 13, 2013 1:29 PM
To: mfd at pwg.org; cloud at pwg.org
Subject: [Cloud] "Support Levels" for the SM2.0/PWG:PJT

All

I was asked to provide a set of (call them) support levels for the SM2.0/PWG:PJT.   I have completed the top level objects and would like feed back on my proposal levels.

All of my documentation is done as C-Code for now.   [For BJSON, JSON, XML or whatever, as you will see later, my code contains a "def" struct for each element/attribute/value which are used for converting internal binary (struct) data.]


Wording for Support Levels:

The Print Job Ticket (PJT) consist of a rich set of printing objects, attributes, elements and values that support the simplest level of printing to most complex.  It supports printing from/in embedded, mobile, home-office, business office and production environments.  However, requiring all Applications and Print Clients in the various environments to support the complete set of PWG: PJT objects, elements, attributes and values would be a burden.   While a Print Service only needs to provide capability information that is supports; currently, a Print Client must support all PWG:PJT objects, elements, attributes and values that any Print Service could potentially provide as a capability; this is just not practical in all situations and environments.   This section provides a solution by defining several Support Levels that a Print Client can advertise to Print Services.

An individual Support Level consist of proper subset of the complete set of PWG:PJT objects, elements, attributes and values.  Currently, there are three Support Levels.   The first level represent "Simple" printing needs, the second level supports nominal/typical office printing and, the third level, represent the full PWG:PJT specification.

Any Print Client or Print Service may elect to implement (advertise and comply to) one of the SM2.0/PWG:PJT Support Levels.  When a Print Client or Print Service declares implementation of a Support Level, the Print Client or Print Service MUST be capable of supporting all objects, elements, attributes and values for that Support Level.  If a Print Client does not declare a specific Support Level implementation, the Print Client SHALL have an assumed Support Level of the most encompassing (all objects, elements, attributes and values) Support Level.

A Print Client MAY advertise to a End-User an object, element, attribute and/or value at a higher Support Level only if the Print Client directly supports that object, element, attribute and/or value.

For example, a Print Client at Support Level 1 MAY advertise "Front Cover" support (a Support Level 2 element); but, the Print Client MUST provide all internal implementation to support a Front Cover.   This is analogous to Print Service with no Front Cover capability but with Print Client support.

A Print Service MUST NOT provide capability data or Print Job Ticket at the Support Level above that of the Print Client.   The Print Client MAY either:
i)                   Reject the Print Job Ticket in it entirety, or
ii)                 Reject the Print Job Ticket for unsupported MUST_HONOR elements, or
iii)               Ignore the unsupported object, element, attribute and/or value.

Please review info at
ftp://ftp.pwg.org/pub/pwg/mfd/white/Proposed.PWG.PJT.Support.Level-2013.02.13.zip

(did not mean to put the last one in cloud directory)

glen



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