ystem) The printing system for Unix computers. Designed by Michael Sweet in the late 1990s, CUPS is the de facto standard for Linux and Unix machines as well as the built-in printing system in the Macintosh as of Mac OS X Version 10.2. Prior to CUPS, LPR/LPD, LP print spooler and LPRng were used in conjunction with the appropriate printer drivers. Apple used Tioga and the Apple Print Manager. See printing system
To PostScript or PDF
For PostScript printers, CUPS converts all input to PostScript, which is fed to the printer. For non-PostScript printers, CUPS converts input to PostScript first, or to PDF if running in the Mac. Using Ghostscript, the PostScript is converted to the CUPS raster format (the Mac uses CoreGraphics to convert PDF to CUPS raster), and the CUPS raster is converted to the printer's language (PCL, ESC/P, etc.).
CUPS also supports host-based printing, in which all control is provided by the CPU (see host-based printing
For network printing, CUPS supports the Internet Printing Protocol (IPP), LPR/LPD and TCP port 9100 (AppSocket). See LPR/LPD