AR-PB2A (serv.man4). Cougar Connectivity Training Pre-course study guide (Glossary of Terms) - Sharp Copying Equipment Handy Guide. Page 13

PPD’s are used with Windows NT, Windows 95 and Apple Macintosh computers to add the basic
machine Information about the printer, such as paper sources, resolution capabilities etc. A “PPD”
is a Postscript “Mini-driver” that ads information to the built in standard drivers within the operating
system.  A “PPD” is basically a text file and because of this, is platform independent. 

The  “PPD” that comes with the AR5132 or AR-280/285/335 Printer Board do not include all the
features that a Full Blown Sharp Specific Printer Driver such as the Postscript Level 2 or PCL
drivers do include.

A Page Description Language devised by Adobe, for producing graphics and text.  Its strength
however is in the reproduction of graphics.

A printer driver translates the output from the application into a print language that can control a
printer.

On a file server network, a print queue would exist on the file server.  This is where all print jobs are
sent to from each workstation temporarily so that they can be prioritised and controlled until the
printer is ready.  When the printer is ready to accept the print job, the data is collected by the print
server and then forwarded to the printer.

A print server can be running as part of a file server or can be running on a dedicated workstation. 
If a workstation is used as a dedicated print server, this cannot also be used as a computer for a
user.  The print server’s job is to monitor the print queue on the file server and “Poll” the queue. 
Polling the queue or de-spooling is where the top job of the queue is taken and transferred to the
printer.