Subject: RE: IPP>MOD - Print by reference

From: Stephen Holmstead <[email-masked]>
Date: Wed, 11 Jun 1997 15:47:30 -0600

Good summary of requirements.  I think that when you narrow 
print-by-reference to this scoping, that is possible in a printer.  I do 
think that there may still be some issues that we need to work through. 
 For example, you will give the printer a URL.  Somehow the printer has to 
be able to distinguish the content of this URL as pre-formatted IPP 
material versus generic web pages.  This might be covered in the content 
description fields.  Also, the printer needs to know if there is a 
pre-formatted type that it can handle (can the printer do postscript?). 
 This might also be covered in the content description.
--
Stephen Holmstead
Hewlett Packard Internet Solutions Operation
[email-masked]

-----Original Message-----
From:	Roger K Debry [SMTP:[email-masked]]
Sent:	Wednesday, June 11, 1997 7:55 AM
To:	[email-masked]
Subject:	IPP>MOD - Print by reference

There has been quite a storm of email on the print by reference subject 
lately.
Let me once again define what I believe to be a very significant customer
requirement that print by reference can satisfy.  In very carefully fencing
this requirement it is important to say what it is not.

It is NOT printing web pages. Much of the concern I have seen expressed in
recent email, especially from HP, has to do with printing web pages. I 
agree
that chasing links and dealing with the multitude of data types on the web 
is
very complex and could potentially bloat a Printer implementation.

It is NOT printing documents that require some security mechanism to
access them. In particular it does not deal with the printing of documents
where the right to print a copy of the document must be purchased.  As
Larry Masinter has suggested, the protocol may reserve some "space"
to encode credentials for such transactions, but I do not want to 
complicate
the model nor hold up approval of IPP as a standard trying to architect and
get approval of these security mechanisms.

There are at least two examples of what I think print by reference is for
version one of IPP:

First, consider the case of documents, such as Internet-Drafts, or those
documents which we have on the PWG ftp site which are accessible
by anonymous ftp, i.e. they are "publically accessible".  Print by
reference is a powerful tool for printing such documents. Documents
are in some print-ready format, such as Postscript.

Second, consider the case where an enterprise keeps a library of
documents (standards, reports, procedures, etc) on a central
repository that is accessible by anyone within the enterprise
firewall. It would probably be on a private internal network. Print
by reference is again a very powerful tool for printing such
documents which are in some print-ready format.

To summarize, this simple version of print-by-reference only
requires that the documents to be fetched are already
formatted for printing.  The Printer does not deal with links,
it does not format pages, it does not deal with dynamic web
formats, etc.

Roger K deBry
Senior Techncial Staff Member
Architecture and Technology
IBM Printing Systems
email: [email-masked]
phone: 1-303-924-4080

---

From: Carl-Uno Manros <[email-masked]>
Date: Wed, 11 Jun 1997 16:03:46 PDT

Stephen and others interested in the print-by-reference discussion,

In our PWG IPP phone conference today, the following proposal was brought up:

It is suggested that we create two new "shadow-operations" for
print-by-reference, one that looks like the Print-Job operation called
Print-URI, which is like Print-Job, but has an attribute containing a URI
instead of the print-data. Similarly one that looks like the Send-Document
but called Send-URI. It will then be crystal clear whether an
implementation supports print-by-reference, by examining whether one or
both of these operations are supported.  The Validate operation will return
an attribute containing information about which operations are supported.
This proposal does not suggest adding additional attributes for security.

I support keeping print-by-reference in our solution as described above,
and meeting the requirements described by Roger deBry (which do not require
security).

Carl-Uno

> This might also be covered in the content description.
Carl-Uno Manros
Principal Engineer - Advanced Printing Standards - Xerox Corporation
701 S. Aviation Blvd., El Segundo, CA, M/S: ESAE-231
Phone +1-310-333 8273, Fax +1-310-333 5514
Email: [email-masked]