>If you have:
> client sends PDL + parameters to gateway
> gateway sends PDL to real printer without parameters
>
>and the PDL is capable of expressing some attributes ("paper size",
>for example), then why not have the gateway just add the parameters to
>the PDL? I know that it's extra implementation work on the part of
>your gateway, but the alternative is to require the same work to be
>done in all clients that want to set paper size; they will need to
>either "always send paper size in the PDL" or else "negotiate over
>where to set paper size and be prepared to send it in the PDL".
>
>Is it really so much harder to take envelope parameters and embed them
>in the data stream?
Larry, we run into a few problems here.
First, is getting the Gateways to change, as you've pointed out.
Spoolers don't typically open, inspect, or modify the print file
unless they are involved in datastream conversion, in which case
they are quite specialized.
Second is the proliferation of PDLs and differences between them.
Servers would have to know how to add parameters in several
different "languages".
Third would be the need for PDL extensions. Not all PDLs have the
same set of functions supported, especially in the area of Job
ticket or management. So, each PDL would have to be extended
separately to accommodate any sort of standard
Fourth, PDLs are (mostly) proprietary. I suppose we could propose
standard extensions to the most popular proprietary PDLs. Hasn't
this sorta been tried before with SPDL? Or, we could ask companies
who control these PDLs to extend and publish in a timely fashion
(which they usual do, when they make extensions).
Last year, before IPP was even a gleam in the PWG's eye, I proposed
an encapsulation scheme - at that point - to associate information
that would be needed for the Job MIB along with the Job during
submission. The idea got a very cool reception. I thought, perhaps {
due to the fact that members who manage PDLs would rather extend
their own. Perhaps my proposal appeared too much like an extension
of "my" PDL (IPDS), or perhaps we just weren't ready for consensus on
the need for a STANDARD means of associating Job information with the
job? No matter, what's important now, is that IPP is driving toward
this same goal.
My recommendation would be, unless we agree on standard extensions to
existing PDLs, we'll have to agree on some, more generic, job
information scheme.
Harry Lewis - IBM Printing Systems