CUPS
Common Unix Printing System ( CUPS) is a free printing system, a daemon which enables printing from the various Unix-like operating systems.
It has been developed by Easy Software Products Company and can be used under both the GPL and under proprietary licenses. It was designed as the successor to older printing systems, such as LPD.
On July 11, 2007 Apple announced to have Michael Sweet, the main developers of CUPS hired. So Apple took over the rights to CUPS. At the same time the ESP Print Pro, a commercial product of Michael Sweet, which is based on CUPS, set.
Architecture
CUPS consists of a client -server architecture; that is, the program is divided into a print client and a print server: The print client sends the print jobs to the print server to handle printing on the computer to which the printer is connected.
The print job from a client is sent to a scheduler, which converts the data to be printed by means of a filter system in the portable PostScript format. This data is finally sent to a backend, which they either printed on the appropriate printer ( and converts the PostScript data for that) or they sent over a network to another CUPS server.
The main advantage of CUPS over other printing systems is that it is a standardized and modularized system that understands a variety of different data on the print server ( for example, PDF files, PNG images, LaTeX texts). With such a system, cross-platform work is possible in heterogeneous networks. In conjunction with Samba can even CUPS files via a virtual Spool print can communicate with which Windows machine.
In a CUPS server, an HTTP server is integrated as standard. This allows on the one hand, a configuration of each computer in the CUPS server network, on the other hand, a certain ease of use is created by a usable without special software control system ( only a browser is required). The CUPS web interface can be addressed under http://localhost:631.
Extensibility
About CUPS backend ( backend filter for further processing of the data) to CUPS can be customized using your own scripts. Some back-end filters are included, such as smb to control Windows printers via Samba, ipp for accessing queues from other hosts on the Internet Printing Protocol, pipe for routing the print job to another program or file for output in a file. Furthermore, there is pap for output to AppleTalk - based printers, eg via Netatalk or Columbia AppleTalk Package ( both AppleTalk file and print server).
User interface
Besides the aforementioned web server front-end, there is a variety of graphical and console-based utilities with which can also be controlled over the network CUPS systems.
- GtkLP - a graphical front-end for GNOME
- KDEPrint a graphical frontend for KDE to KDE3
- ESP Print Pro - a graphical frontend of Easy Software Productions ( producers of CUPS)
- Under the ZETA Print_Kit can also access a CUPS subsystem, and in addition to the ZETA printer drivers also ported CUPS driver together with corresponding PPD files are supported. To communicate the Print_Kit and the spooler via CUPS driver with the printers that are described by PPD files.
- The Printer Utility in Mac OS X
- Some Linux distributions have their own GUIs.
- For the operating system eComStation the system is being developed as ECUPS.
Criticism
With version 1.6 Apple did remove some features that are for Linux systems and Unix systems is important because they are not needed for Mac OS X. These include various filters to convert various text and bitmap formats to PostScript and a function to query the available printer queues. The filter design was then taken over by the OpenPrinting Project, while the CUPS own functionality to detect print queues for some time by the support of system-wide Zeroconf service was unnecessary. With Avahi is an implementation for Linux systems available, so this brings no functionality limitation with it.