[IPP] Potential errata/update for PWG Raster Format and/or IPP Everywhere specs

[IPP] Potential errata/update for PWG Raster Format and/or IPP Everywhere specs

[IPP] Potential errata/update for PWG Raster Format and/or IPP Everywhere specs

Ira McDonald blueroofmusic at gmail.com
Wed May 21 16:48:08 UTC 2014


Hi,

I agree with Bill's comments.

I suggest that the Implementors Guide should document that the intended
meaning of 'attempted' in RFC 2911 was and is 'best-effort'.  There is no
wiggle room in RFC 2911 (page 139), in my reading, that the Printer can
say 'attempted' and then NOT make the attempt.

I agree that making 'attempted' REQUIRED is cold comfort to Clients.

I suggest that the definition of 'guaranteed' (NOT defined in RFC 2911,
but rather in section 11 of JSP2, PWG 5100.11-2010) is so convoluted
that it is not practical to implement.

Cheers,
- Ira


Ira McDonald (Musician / Software Architect)
Co-Chair - TCG Trusted Mobility Solutions WG
Chair - Linux Foundation Open Printing WG
Secretary - IEEE-ISTO Printer Working Group
Co-Chair - IEEE-ISTO PWG Internet Printing Protocol WG
IETF Designated Expert - IPP & Printer MIB
Blue Roof Music / High North Inc
http://sites.google.com/site/blueroofmusic
http://sites.google.com/site/highnorthinc
mailto: blueroofmusic at gmail.com
Winter  579 Park Place  Saline, MI  48176  734-944-0094
Summer  PO Box 221  Grand Marais, MI 49839  906-494-2434



On Wed, May 21, 2014 at 12:26 PM, William A Wagner <wamwagner at comcast.net>wrote:

> As Ira suggests, I believe that it is very difficult to “guarantee”
> successful override, considering the potential complexity and variations in
> the PDL.  But ‘attempted’ is squishy  and making it REQUIRED  might tempt
> some to report ‘attempted’ even when the attempt is halfhearted (or
> non-existent). That would make the value even more unreliable. Perhaps we
> should have allowed a value of ‘best effort’  meaning that the printer will
> really try. But I think making ‘attempted’ a minimum REQUIRED response may
> just increase uncertainty. Better that the User understand that he is stuck
> with what is in the PDL  if there is not  very good likelihood that  the
> overrides will be completely successful.
>
> Thanks,
>
> Bill Wagner
>
>
>
> *From:* ipp-bounces at pwg.org [mailto:ipp-bounces at pwg.org] *On Behalf Of *Ira
> McDonald
> *Sent:* Wednesday, May 21, 2014 11:42 AM
> *To:* Kennedy, Smith (Wireless Architect); Ira McDonald
> *Cc:* <ipp at pwg.org>
> *Subject:* Re: [IPP] Potential errata/update for PWG Raster Format and/or
> IPP Everywhere specs
>
>
>
> Hi Smith,
>
> We've never made "pdl-override-supported" have 'guaranteed' as REQUIRED
>
> (even in IPP/2.1 or IPP/2.2 levels), because it's binary.
>
> If you claim that your Printer supports 'guaranteed' then you have to be
> able to
> *successfully* intercept and override everything in your interpreters
> (vanishingly
> unlikely in PDF, for example).
>
>
>
> I agree with Mike that I've never seen a printer in the wild that actually
> supported
>
> 'guaranteed'.
>
> I also agree that should make 'attempted' a REQUIRED value and 'guaranteed'
>
> a RECOMMENDED value (explaining in the Implementors Guide that there are
>
> practical limitations w/ third-party interpreters to perfect override).
>
> Cheers,
>
> - Ira
>
>
>
>  Cheers,
>
> - Ira
>
>
>  Ira McDonald (Musician / Software Architect)
> Co-Chair - TCG Trusted Mobility Solutions WG
> Chair - Linux Foundation Open Printing WG
> Secretary - IEEE-ISTO Printer Working Group
> Co-Chair - IEEE-ISTO PWG Internet Printing Protocol WG
> IETF Designated Expert - IPP & Printer MIB
> Blue Roof Music / High North Inc
> http://sites.google.com/site/blueroofmusic
> http://sites.google.com/site/highnorthinc
> mailto: blueroofmusic at gmail.com
> Winter  579 Park Place  Saline, MI  48176  734-944-0094
> Summer  PO Box 221  Grand Marais, MI 49839  906-494-2434
>
>
>
> On Wed, May 21, 2014 at 11:22 AM, Kennedy, Smith (Wireless Architect) <
> smith.kennedy at hp.com> wrote:
>
> Hi Mike,
>
> Since “attempted” is so squishy, why not mandate “guaranteed”?  Including
> “attempted” seems like a loophole.
>
> Smith
>
> /**
>     Smith Kennedy
>     ATB Wireless Architect - PPS
>     Hewlett-Packard Co.
> */
>
>
>
>
> On 2014-05-21, at 7:42 AM, Michael Sweet <msweet at apple.com> wrote:
>
> > All,
> >
> > It has come to my attention that neither the IPP Everywhere nor the PWG
> Raster Format specs explicitly call out required values for the
> "pdl-override-supported" Printer attribute. This attribute specifies
> whether the Printer can override embedded job ticket information (such as
> media size) when requested in a Job via the "ipp-attribute-fidelity" or
> "job-mandatory-attributes" Job Template attributes.
> >
> > Generally speaking, Printers SHOULD support PDL override for the
> standard PDLs in IPP Everywhere, including PWG Raster, JPEG, and PDF.
>  Typically this means forcing prints to a single media/size or forcing
> simplex/duplex output, and is particularly important for JPEG.
> >
> > My recommendation is for us to add the following conformance statement
> in a future revision of the IPP Everywhere specification:
> >
> >    pdl-override-supported (type2 keyword)
> >
> >    When reporting capabilities for the 'application/pdf', 'image/jpeg',
> or 'image/pwg-raster'
> >    MIME media types, Printers MUST report either 'attempted' or
> 'guaranteed' for the
> >    "pdl-override-supported" Printer attribute,
> >
> > Thoughts?
> >
> > _________________________________________________________
> > Michael Sweet, Senior Printing System Engineer, PWG Chair
> >
>
> > _______________________________________________
> > ipp mailing list
> > ipp at pwg.org
> > https://www.pwg.org/mailman/listinfo/ipp
>
>
> _______________________________________________
> ipp mailing list
> ipp at pwg.org
> https://www.pwg.org/mailman/listinfo/ipp
>
>
>
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