PostScript Printer Description
Encyclopedia
PostScript Printer Description (PPD) files are created by vendors to describe the entire set of features and capabilities available for their PostScript
PostScript
PostScript is a dynamically typed concatenative programming language created by John Warnock and Charles Geschke in 1982. It is best known for its use as a page description language in the electronic and desktop publishing areas. Adobe PostScript 3 is also the worldwide printing and imaging...

 printers.

A PPD also contains the PostScript code (commands) used to invoke features for the print job
Print job
In computing, a print job is a file or set of files that has been submitted to be printed.Jobs are typically identified by a unique number, and are assigned to a particular destination, usually a printer...

. As such, PPDs function as drivers for all PostScript printers, by providing a unified interface for the printer's capabilities and features. For example, a generic PPD file for all models of HP Color LaserJet contains:

*%


*% Basic Device Capabilities
*%

*LanguageLevel: "2"
*ColorDevice: True
*DefaultColorSpace: CMYK
*TTRasterizer: Type42
*FileSystem: False
*Throughput: "10"

which specifies that the printer understands PostScript Level 2, is a color device, and so forth. The PPD can describe allowable paper sizes, memory configurations, the minimum font set for the printer, and even specify a tree-based user interface for printer-specific configuration.

CUPS

CUPS uses PPD drivers for all of its PostScript printers, and has even extended the concept to allow for PostScript printing to non-PostScript printing devices, by directing output through a CUPS filter. Such a file is no longer a standard PPD, but rather a "CUPS-PPD".
CUPS clients usually read the current PPD file from the server every time a new print job is created.

Windows

Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

also uses PPD files but converts these to a binary file format before using them. These are normally stored in C:\WINDOWS\system32\spool\drivers\w32x86\3. Updating the PPD files requires removing and then reinstalling the printer.

MIME Type

The MIME type for the CUPS variant of PPD is application/vnd.cups.ppd. Apparently, this is not the case for non-CUPS PPD files, which seems to be text/plain.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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