Novell LINUX ENTERPRISE SERVER 10 - INSTALLATION AND ADMINISTRATION 11-05-2007, Installation Manual

Page: 455 / 982

23.1 The Workflow of the Printing
System
The user creates a print job. The print job consists of the data to print plus information
for the spooler, such as the name of the printer or the name of the printer queue, and,
optionally, information for the filter, such as printer-specific options.
At least one dedicated printer queue exists for every printer. The spooler holds the print
job in the queue until the desired printer is ready to receive data. When the printer is
ready, the spooler sends the data through the filter and back-end to the printer.
The filter converts the data generated by the application that is printing (usually
PostScript or PDF, but also ASCII, JPEG, etc.) into printer-specific data (PostScript,
PCL, ESC/P, etc.). The features of the printer are described in the PPD files. A PPD
file contains printer-specific options with the parameters needed to enable them on the
printer. The filter system makes sure that options selected by the user are enabled.
If you use a PostScript printer, the filter system converts the data into printer-specific
PostScript. This does not require a printer driver. If you use a non-PostScript printer,
the filter system converts the data into printer-specific data using Ghostscript. This re-
quires a Ghostscript printer driver suitable for your printer. The back-end receives the
printer-specific data from the filter then passes it to the printer.
23.2 Methods and Protocols for
Connecting Printers
There are various possibilities for connecting a printer to the system. The configuration
of the CUPS print system does not distinguish between a local printer and a printer
connected to the system over the network. In Linux, local printers must be connected
as described in the manual of the printer manufacturer. CUPS supports serial, USB,
parallel, and SCSI connections. For more information about the printer connection,
read the article CUPS in a Nutshell in the Support Database at
http://en.opensuse
.org/SDB:CUPS_in_a_Nutshell
.
Printer Operation 437