To fully use the functionality of a Postscript printer on Unix,
the system needs a Postscript Printer Description (PPD) file,
which is a file in a standard format defined by Adobe. It
describes the options the printer has and how to control them.
When a print dialog is presented to the user (either by an
explicit call to , or by printing), the system uses the PPD file
to find what additional options to present, and how to
communicate them to the printer. A PPD file should be supplied
by the manufacturer with the printer itself. Otherwise, it is
normally possible to obtain the PPD file from the website of the
manufacturer. The name of a PPD file should be printername.ppd.
When the user configures a new printer, the first thing the
system does is to show the user all the PPD files that it can
find under the (directly, or one level of directories below it).
The application should set this variable to the appropriate
directory. If the value of , the system looks at the directory
obtained by evaluating If the prin