[Desktop_printing] Usability: Printing roles, tasks and environments

Henrique de Moraes Holschuh hmh at debian.org
Wed Mar 8 08:12:38 PST 2006

On Wed, 08 Mar 2006, Till Kamppeter wrote:
> >>    Name (queue name, sometimes human-readable, e.g. "LJ4000")
> >>    Description (human-readable text, e.g. "HP LaserJet 4000")
> >>    Location (human-readable text, e.g. "Building 4 Room 301")
> >>    Device URI (geek-readable, e.g. "ipp://")
> >>    Printer Driver (PPD filename, e.g. "hp4000_6.ppd")
> >>    Page Size (e.g. "Letter", "A4", etc.)
> >>
> >>Most of this can be auto-assigned via device discovery, and this is
> >>how CUPS 1.2 does things...
> > 
> > that means CUPS also knows about the proper ppd file when a printer is
> > connected to a computer (plug-and-play)?
> > 
> In the PPD files the entries "Manufacturer" and "Product" should
> correspond to manufacturer ("MFG:") and model ("MDL:") in the IEEE-1284
> device ID string. More items of the device ID string can be in the
> "1284DeviceID" entry of the PPD file.

(I will use HP printers as an example because that's what I have some
experience with, being the Debian HPLIP maintainer and onwer of a few HP

You'd need a mapping table of some sort, preferably a regexp-enabled one
with fuzzy capabilities if you want to be really generic.  I recall
complains and some changes to HPLIP to accomodate n:1 mappings in the
IEEE-1284 IDs, for example.  It also needs to do fuzzy-matching to find the
correct PPD, because you quite often have a n:m (m often > 1) relationship
with PPDs due to printer series.

IMHO the failsafe way to go about it is to add printer setup helper plugins
that allow a driver to extend CUPS' capabilities of printer detection, PPD
selection, and printer capability detection.  Anything else is just wishful
thinking, IMHO.

That way, we could, e.g. teach CUPS to locate HP printers in the network, to
select the correct PPD using euristics appropriate to HP printers when
dealing with an HP device, and to auto-setup the accessories in HP printers
through the SNMP-like queries they offer or through their device-id replies.

Not to mention also extending CUPS to detect a MFP printer as a printer and
a print-to-fax device, for example, and thus setup two queues at once, or
allow the user to select which type of queue he wants to setup.

> It seems that the accessories cannot be auto-detected by the computer
> with some standard method. The available choices of these options are
> selected by the printer manufacturer depending on which accessories are
> really supported by the printer.

Well, a lot of the low-end devices do not allow for much on the way of
auto-detection, so the Windows drivers have "setup printer accessories"
tabs.  We may need to do something like that in CUPS.

  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh

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