Kelly,
I hope Google will take this opportunity to semantically aligned with the printing industry. It would not take much of an effort to reuse the semantic elements as defined by the PWG in your CDD format. The industry has been driving towards a common model for more than 20 years. See <ftp://ftp.pwg.org/pub/pwg/mfd/white/SemanticEvolution-PWG.pdf>. It is a mistake to try and unify two antiquated data representations that were specific to a driver based environment (i.e., PPD and devmode which was the basis for the XPS print ticket).
Virtually every manufacturer of Printers and MFDs implements the PWG Semantic Model. It is a great cost savings to our companies to implement the semantics of a feature once and provide simple syntactic protocol gateways (e.g., IPP. WS-Print, JDF Digital Print, DLNA Print) to incorporate our devices in various network environments/ecosystems. I have no problem with Google picking a subset of features that matches its needs, but you should select those elements from the semantic elements defined by the PWG. If there are features that have not been accommodated in the model then either it will be a Google specific extension or Google could elect to have the PWG Semantic Model extended to accommodate the missing feature. I'm sure you would be able to get enthusiastic support from the PWG to assist you in modifying your Protobuf definitions for the mapping. (It will be easier than the PPD and XPS Print Ticket mapping they are already doing.) The PWG has had liaisons with several standards groups to align the data models across the industry.
There are subtleties that are waiting on implementations to trip over. Simple things like precise definition for "horizontal" for impressions and scans. Little things like the correct mapping of ppm from float to int which probably won't be much of an issue since most speeds are integer values which begs the question "why bother with a float for this?". If cloud printing scales up to production class printers down the road elements like "duplex" will be problematic since it is not semantically the same as "sides". In addition to which side of the media is being printed on and the orientation of the impressions on both sides, imposition is also included in "duplex".
The PWG Semantic Model scales from a little dongle that hangs of the parallel port of old printers up to tree eating monolithic digital presses. The PWG Semantic Model is the result of more than 20 years of work by subject matter experts in the industry and has industry wide support. Even with a common model wide variability exists in the functionality and target markets for various mappings (e.g., DLNA printing vs. JDF Digital printing).
At least that is my opinion,
Pete
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 K.D. Lucas
Sent: Monday, January 28, 2013 12:38 AM
To: cloud at pwg.org
Subject: [Cloud] Semantic Parsing of Capabilities: Cloud Device Description Capabilities
Hello Cloud Print Aficionados,
I wanted to inform you that the Google Cloud Print team is proposing a new capabilities format that will allow us to take advantage of semantic options, something we're calling Cloud Device Description (CDD) format, and can be used from printers to a host of other devices that may be used with our service.
This is our rough draft of our proposal. We are proposing this capabilities format in order to provide a more uniform experience for our Cloud Print users, as correctly parsing various PPD files is challenging and ultimately not feasible.
Since I know this group has thought about Cloud Printing for quite some time, and has significant experience with the issues around Cloud Printing, we welcome any feedback or comments you might have. I've attached the specification as a PDF file.
I won't be around to make your next face-to-face meeting, but I've been reading some of the emails regarding this meeting.
Regards,
Kelly
kdLucas
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