Do either of you object if we put this on the PMP/WIMS mailing list and
include it in the face-to-face discussion?
With respect to Ira's comments, one may argue that design requirements 5-7
. should support automatic device driver installation by client and
server operating systems (see section 3.2).
. should support interoperable advertising of implemented document
formats by network spoolers and network Printers (see sections 3.1 and 3.2).
. should support interoperable discovery of available document
formats by Imaging Clients and Imaging Servers (see sections 3.1 and 3.2).
would suggest a document format method that did distinguish between
variations on a language without the need for creating a slew of
vendor-specific language identifications.
From: Ira McDonald [mailto:blueroofmusic at gmail.com]
Sent: Wednesday, January 27, 2010 3:29 PM
To: William Wagner; wims at pwg.org; Ira McDonald
Cc: Jerry Thrasher
Subject: Re: [PDL versions?] PWG last call - Command Set Format - IEEE1284
Device ID -25 Feb 2010
The short answers to your questions are:
(1) Distinguishing Emulation from Genuine was not a
(2) Distinguishing PDL versions was also not a design
objective (or plausibly interoperable).
- The use and misuse of the corresponding version
elements in the Printer MIB v1/v2 prtInterpreterTable
is a hopeless mess.
- Nobody was willing to let the editors to address this
when we did Printer MIB v2.
So, inserting version information may work for a given
vendor, but completely breaks interoperability across
different spoolers and OS environments.
We could perhaps introduce a syntax for version
suffixes, but the chances that vendors will correctly
implement it seems very unlikely.
Bearing in mind the machine-readability imperative,
do you have an interoperable version suffix format
Or an interoperable Emulation versus Genuine suffix
- Ira (1284 Cmd Set editor)
Ira McDonald (Musician / Software Architect)
Chair - Linux Foundation Open Printing WG
Co-Chair - TCG Hardcopy WG
IETF Designated Expert - IPP & Printer MIB
Blue Roof Music/High North Inc
email: blueroofmusic at gmail.com
579 Park Place Saline, MI 48176
PO Box 221 Grand Marais, MI 49839
On Wed, Jan 27, 2010 at 11:58 AM, William Wagner <wamwagner at comcast.net>
I am sending your questions onto Ira. I think your two points are very good
ones. My take on them:
The spec allows for PrtInterpreterLangFamilyTC, mime-media-type, and Private
type designations. PrtInterpreterLangFamilyTC does not provide for version
and emulation variations; mime-types for all of the variations do not exist,
and would be cumbersome if they were to be all registered; and having
applications understand the difference between private types is unrealistic.
The intent is machine identification of the command language. Just
indicating (by an appropriate means. placing "emulation" after the
designation does not appear consistent with the spec) that a pdl is an
emulation warns the interpreter that there may be differences from the
defined set, but these will likely be different from one emulation to
another. I think the best approach depends on how good the emulation is (as
an emulation, not as a PDL). But, barring having to define and designate
each emulation as a separate PDL, there might be some benefit in somehow
flagging that a PDL might deviate somewhat from the defined language.
Major Version differences are likely more drastic, more likely to be
independently defined and since there should be fewer of them that possible
emulations, more amenable to being listed as separate MIB or MIME types.
That is, there is little advantage in knowing the language is up-version
(other than expecting differences) unless the interpreter knows what the
differences are. To be able to do this, the version and its definitive
reference should be identified in a standard way. The problem then, of
course, is who is going to register these versions.
Thanks for the input.
01/27/2010 09:07 AM
"William Wagner" <wamwagner at comcast.net>
Re: [Pwg-Announce] PWG last call - Command Set Format - IEEE1284 Device
ID -25 Feb 2010
A couple of questions have come up with respect to what's really required to
be done and what
can be done with respect to two particular issues.
1. The percieve requirement for not confusing PDL emulation with "true" PDL
Example, Postscript Emulation vs. Adobe PostScript and PCL Emulation vs. HP
2. The need for the ability for versioning of the various PDLs.
PCL 6 is very different from PCL 3 (most low end inkjet printers still
support only PCL 3, the first
PCL to support color).
So here's what I'm talking about from a real string.
If the current CMD string is:
COMMAND SET:PCL 6 Emulation, PostScript Level 3 Emulation, NPAP, PJL;
Would a compliant string simply be:
COMMAND SET:PCL,PS,PCL 6 Emulation, PostScript Level 3 Emulation, NPAP, PJL;
Senior Engineer, WW Corporate Standards
C14/082-1, 740 New Circle Rd, Lexington Ky 40550
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