The KDEPrint Handbook
Copyright © 2001 Kurt Pfeifle
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".
This handbook describes KDEPrint. KDEPrint is not a standalone program. It is the new printing framework for KDE 2.2. KDEPrint is an intermediate layer between KDE (or other) applications and the selected (and installed) print subsystem of your OS (operating system).
Table of Contents
List of Examples
This handbook describes KDEPrint. KDEPrint is not a standalone program. It is the new printing framework for KDE 2.2. KDEPrint is an intermediate layer between KDE (or other) applications and the selected (and installed) print subsystem of your OS (operating system).
It should be noted that both the developer of this application, and the author of this document are most familiar with CUPS as a printing system. At the time of writing, CUPS is the best supported printing subsystem, and it is the best documented.
This handbook is a work in progress, and later versions of the KDEPrint software and editions of this handbook will support and explore more closely other printing systems.
In the meantime, even if your printing subsystem is not yet well covered, you are encouraged to explore the Printing Manager module in KControl, and you will find its operation to hopefully be fairly self evident, no matter what printing subsystem you use.
Lauri Watts, KDE documentation team
This chapter aims to give a technical overview of KDEPrint which non-programmers can comprehend.
KDEPrint is a new and revolutionary tool to give easy access to printing services for both KDE users and KDE developers.
You can access the functions of KDEPrint in different ways: through the Printing Manger in the KControl, through the kprinter command or through the dialogue that pops up if you want to print.
KDEPrint is not a replacement for the printing subsystem itself. KDEPrint does not therefore give provision for spooling, and it does not do the basic processing of PostScript® or other print data.
KDEPrint is an intermediate layer between the spooling and the data processing print subsystem (as installed), and the application that seeks to print. KDEPrint provides a common interface for KDE developers and KDE users, to various supported print subsystems. At the same time, it is customisable, and highly configurable.
KDEPrint is easy to use for both KDE developers and end-users. Developers can port their applications, with minimal changes, to use KDEPrint instead of the old Qt™ print “system”. Users can easily choose and configure their print subsystem.
For a reference to new KDE users: Qt™ is the basic library and graphical toolkit, which is used by all KDE applications; Qt™ is developed by TrollTech, a Norwegian software company.
KDEPrint has different faces for different people.
KDEPrint allows users and/or administrators, depending on their rights, access to printing subsystems (CUPS, LPD, RLPR, LPRng, PDQ etc.) through a KDE graphical user interface (GUI). Using KDEPrint, they can print, administer jobs, printers and the printing daemon, all in a comfortable manner.
Experienced users will like the capability to plug any working filter for the print data between the output of their application and the input, into the chosen print subsystem. Some examples for this already ship with “plain vanilla” KDEPrint. Read on.
If a KDE developer needs printing access for his application, he does not code the printing functions from scratch. Before KDE 2.2 this service was provided by the QPrinter class, a library function of the Qt™ Toolkit. The QPrinter class relied on the out-moded “Line Printer Daemon” (LPD). The KDEPrint library bases itself firmly on the more modern Common UNIX® Printing System (CUPS), while at the same time keeping backward compatibility with LPD and other legacy, or less elaborate, print systems. It also “leaves the door open” for any new development that might occur.
For KDE developers to use the new KDEPrint class in their applications, they require only minimal changes to their code: for every call of QPrinter, they just need to change this to KPrinter. Replacing one (!) letter in a few spots, and automatically they are done; their application can then use all of the features of the new KDEPrint library.
More ambitious developers, or ones with special requirements, can do more: despite KDEPrint's feature-rich framework, they are still able to customise the print dialogue of their application by creating an additional “Tab”, where their extensions to the standard KDEPrint will feel right at home.
This last mentioned feature has not been used widely inside KDE so far, as developers are not yet fully aware of KDEPrint's power. Expect more of this in the near future. One example I discovered is the KCron application. It lets you edit the crontab through a GUI. The developers have implemented a printing feature that lets you (or root) choose if you want to print the whole of crontab (for all users) or just the part that is marked. You can see the effects on KDEPrint in the following screenshots.
This shot shows a sample from the KCron utility.
The dialogue to configure KCron's printing options: the additional tab titled Cron Options is from inside KCron, not KDEPrint; it is a special extension added by the KCron developers for printing purposes, not originating from, but executed by KDEPrint. Developers of other applications are free to implement their own goodies, if they feel need for it.
KCron's addition to the KDEPrint dialogue.
KDEPrint's easy-to-use interface for all supported print subsystems of course does not eliminate basic traditional weaknesses of some of those systems. But it smooths some rough edges. Different users may use different printing systems on the same box. A user is free to even switch “on the fly”, from the print dialogue, the print subsystem to be used for the next job. (This is possible if different systems are installed in a way that they don't “get in each other's way”.)
Most UNIX® users are used to LPD printing. LPD provides only basic printing functions, is very inflexible and does not utilise the many options of more modern print systems like CUPS. While also working remotely over any distance (like every TCP/IP based protocol), LPD lacks bi-directional communication, authentication, access control and encryption support.
KDEPrint can use CUPS to support:
Querying the LAN for available printers,
Basic, Digest, and Certificate Authentication,
Access Control based on IP addresses, net addresses, netmasks, host- and domain names,
and 128-Bit TLS or SSL3 encryption of print data, to prevent eavesdropping, or at least make it much more difficult.
This makes KDEPrint a much more robust and reliable solution than using the venerable LPD.
You get access to KDEPrint, or parts of it, in four different ways:
through your applications: if you call the printing dialogue (either File+Print...) or the button with the little printer icon on it; this opens the printing dialogue.
through the typed command kprinter in a terminal or a Konsole window or from the Run Command... mini-CLI window: this also opens the printing dialogue.
from the 
button, starting KControl, and then go to System+Printing Manager. This opens the KDEPrint administration which is part of the KDE Control Centre and also lets you switch to other parts of the KControl
from a command line (Konsole or mini-CLI) type kcmshell . This opens just the KDEPrint part of KControl to change your settings printmgr
Starting the kprinter dialogue from a Run Command... window.
Here is a Kivio drawing of the kprinter dialogue as it pops up after being started... You can always add a new printer by clicking on the small Wizard button (marked red/yellow in this drawing).
kprinter dialogue started (Kivio draft drawing)
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The new KDEPrint system includes more than one highlight. Having worked in an environment in the past that is not exactly sophisticated, as far as printing is concerned, take a look at some of the benefits that come with KDEPrint
KDEPrint has an “Add Printer Wizard”. The Add Printer Wizard helps you with adding and configuring a new printer. Of course, you may do this manually as well.
KDEPrint helps you “discover” printers. It is able to scan the environment for available devices and queues. This works for network connections using TCP (AppSocket, aka HP® JetDirect®, or IPP) or SMB/Samba (“shared” Windows®) printers and partially for directly attached printers over parallel, serial, or USB connections.
The wizard makes the installation and handling of the drivers “a snap”. Selecting, configuring and testing should be easy as never before on any Linux®-like system.
The Print Job Viewer is automatically started by kprinter. It may be docked into the KDE panel (in the system tray). The Print Job Viewer allows full job management, if supported by the print subsystem.
You can:
Hold and release jobs,
Move pending jobs to another printer,
Cancel pending or processing jobs.
A screenshot of the KDEPrint PrintJob Viewer shows the information you get: Job-ID, target printer, job name, job owner, job status and job size. In the next KDEPrint release you will also see information about the number of pages (as CUPS calculates it; see chapter on page accounting for more information about its merits and limitations).
A screenshot of the KDEPrint PrintJob Viewer.
An alternative way to looking at the same information (and having the same amount of control is through the KDE Control Centre selecting System+Printing Manager. If you don't see the Printer Information, click on the window background and select View Printer Information. Then go to the Jobs tab to see this:
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KDEPrint uses different modules to realise the interface to the possible print subsystems. Not all the modules are yet developed fully, but you will have basic printing functionality with:
LPD (BSD style)
LPRng (Red Hat®, if you just use it's BSD style subset),
RLPR (a command-line LPR utility, which doesn't need a printcap file.
“external” print commands (Netscape® like).
Most importantly, full support for CUPS is already there. Modules for other print subsystems, such as PLP, PPR and PDQ may be available later.
KDEPrint makes KDE much more flexible. It gives freedom of choice to KDE 2.2 users. To use different available print subsystems, these must, of course, be installed independently from KDE. In former versions, users were stuck with the old LPD style print subsystems. Now they can even use CUPS. In the future, there will be easy integration of new subsystems, as they appear on the scene.
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Some specific features of KDEPrint depend on the chosen print subsystem. This dependency might exist because those features are only implemented there; remember, KDEPrint is an intermediate layer between KDE applications, and the print subsystem, but it's no replacement for any print subsystem by itself. Such dependency may exist for another reason: that KDEPrint has not yet implemented an interface to all the features of all the subsystems.
Other features include benefits from KDEPrint that are independent of the chosen print subsystem, and are available with all of them. At present there are “special” or “virtual” printers, and some generic “pre-filters”.
From the Print Dialogue, you can select to look at a preview. For this, the print file is passed through filters which make it suitable for displaying on screen using KGhostView.
Amongst these additional KDEPrint features are a few “special” or “virtual” printers:
These special printers may:
Convert your document into a PDF file with the help of an external program.
Send your document as an email attached PDF file.
Save your document as a PostScript® file.
Send it through an available backend, such as Hylafax as a fax.
These “special” printers appear in the user print dialogue just like “normal” printers. They are entirely configurable on a per-user basis.
KDEPrint provides you with a framework to define and configure your own “pre-filters”. These pre-filters may take effect before they are passed to your print subsystem for further processing, but after the (PostScript®, plain text or other) print files have been generated by your application.
There are a few useful filters already predefined. These are:
The “multiple pages per sheet” filter,
the “enscript” text filter,
and three filters to help print pamphlets.
You may create your own filters based on any third party program that is able to process PostScript®, plain text or image files, and output any one of those formats.
These filters are configured through XML files. This makes an extension of the concept very easy for experienced developers, but end-user configuration is also done through an intuitive graphical user interface. So, fear not, you don't need to learn XML because of KDEPrint!
This is a predefined filter that installs with KDEPrint. It allows you to create a modified PostScript® output, from PostScript® input, that prints 1, 2, or 4 logical pages on a single sheet of paper.
This is a predefined filter that installs with KDEPrint. It allows you to create PostScript® output from any text file input, that includes syntax highlighting for program listings, pretty-printing, and nice configurable page frames and headers.
If your printer is able to produce duplex output, using either one-pass or two-pass technology, you may be able to use one, or a combination, of the “pamphlet” filters.
For duplexing printers, make sure you use the duplex option that “turns” the output along the short paper edge. Folding the printed paper along the middle turns your document into a nice pamphlet.
If you are stuck with using a simplex-only device, you can do the same, using two different filters and a few additional steps.
Depending on your model, first use the filter for printing the “odd” pages, then insert the paper in the correct order back into the paper tray to get the even pages printed on the reverse side. These can then be folded to make a pamphlet.
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KDEPrint contains a module for CUPS. CUPS, the “Common UNIX® Printing System” (http://www.cups.org/), is the most advanced, powerful and flexible of all print subsystems on UNIX® and other UNIX®-like operating systems. It is still quite new on the horizon, but is based on IPP, the Internet Printing Protocol, the newly emerging standard for the future of network printing. CUPS is clearly the print system of choice for Michael Goffioul, the principal KDEPrint developer.
Experienced KDE users may already be familiar with Michael's utilities qtcups and kups (co-developed with Jean-Eric Cuendet). These were, up until now, the graphical GUI front ends for CUPS with a strong relation to KDE.
Both utilities are probably still widely used. For those not familiar with them, here are brief explanations.
qtcups was a graphical front end for the lp or lpr print commands as installed by CUPS. Using qtcups opened a dialogue. This dialogue let you comfortably select your printer and the print job options. qtcups worked from the command line, or from within applications, when the application in question had a configurable print command.
kups was a graphical wrapper to do the administration tasks for your CUPS server, and the CUPS daemon at the heart of it. You could add, delete, modify, configure, start, and stop printers. You could cancel, delete, move, stop and restart print jobs, and you could change the settings of the daemon, start, stop, and restart it.
The CUPS Module in KDEPrint now contains all (and more) functions that were provided by qtcups and kups in former KDE versions.
Instead of qtcups you can now use the kprinter command. And in place of kups you will probably use kcmshell printmgr from now on.
The KDEPrint module for CUPS also lets you fully administer the print subsystem, just like kups did before. It can start, stop and configure your CUPS daemon. It can also start, stop, add and delete “printers” (i.e. printer queues) and printer “instances”. Printer instances are printer queues that point to the same physical output device but with a different default setting of print options.
KDEPrint's CUPS module gives you access to a “graphical print command”, like qtcups did before.
Use kprinter in any application, even a non-KDE application, that lets you configure your print command. Examples of these are Netscape® and StarOffice, but not most pre-KDE 2.2 programs.
A screenshot how to use the new kprinter print command instead of the old-fashioned lpr... Of course you need to have kprinter in your $PATH, or give the full path in the dialogue; e.g. /opt/kde/bin/kprinter
You can also use kprinter from the command line and see the resulting dialogue box pop up:
Just make sure you give at least the file to be printed from the command line as well: kprinter . This will hand over the CUPS Software Administrator Manual to the kprinter dialogue, which will then pop up with the default printer pre-selected./usr/share/doc/packages/cups/sam.pdf
To pre-select a specific printer from the command line, use the -d option, e.g.: kprinter . You can still de-select the printer -d DANKAcolorC2000 /home/kurt/linuxtag2001-paper.psDANKAcolorC2000 and choose a different one.
You cannot however call kprinter without a print file and hope to open a file selection dialogue box from the kprinter window. This is a feature that will be implemented only in the next version.
Using kprinter you are able to “ring all the bells and blow all the whistles” of your printer. You will need a device-specific so-called PPD (PostScript® Printer Description) to enable CUPS to make this nice tandem team do this for you. Read more about this in the section called “Device Dependent Print Options”.
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What you have now is the first, already very feature-rich version of KDEPrint. This version is, of course, fully usable for printing. You might even think that “it was never so easy” (not even back in the days when you had to use Microsoft® Windows®).
In the future, KDEPrint will become even better. It will do a better job of “detecting” your installed print subsystem itself. Already KDEPrint is doing quite well in automatically sensing if you have CUPS on your system. But in many cases you will have to tell KDEPrint what you are using, if you want to keep a legacy print system.
The most important improvement in the near future will be a completion of the LPRng plugin. This at present is still very basic. It is restricted to the pure classical LPD part of LPRng.
Also, you may be able to add printers directly from the print dialogue to your system “just in time”, without going to KControl first.
Some smaller improvements already planned are:
add a file selection dialogue from the kprinter window to allow combining of additional files to the present printjob
add a “history” button to the KJobViewer window and also a column to show the number of pages CUPS calculates for the job.
Finally, there will be an “IO slave” that will give you access to your print subsystem, via Konqueror for example. With this you will soon be able to browse your print subsystem from Konqueror through a URL like shortcut such as print://printers/printername. A KPart will add a virtual folder to the services section of the Konqueror navigation panel, giving a nice integrated way to browse and manage your print system via the URL print:/manager.
Please contact Michael Goffioul at (kdeprint AT swing.be) with any further user or developer suggestions.
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This chapter aims to give a bit of theoretical background to printing in general, and to CUPS especially. If you are not in need of this, you might like to skip ahead to the next chapter. Chances are you will come back to this chapter at some point anyway, because sometimes one needs extra theory to solve a practical problem.
Printing is one of the more complicated chapters in IT technology.
Earlier on in history, every developer of a program that was capable of producing printable output had to write his own printer drivers too. That was quite complicated, because different programs have different file formats. Even programs with the same purpose, for example: word processors, often do not understand each other's formats. There was therefore no common interface to all printers, hence the programmers often supported only a few selected models.
A new device appearing on the market required the program authors to write a new driver if they wanted their program to support it. Also for manufacturers, it was impossible to make sure their device was supported by any program known to the world (although there were far fewer than today).
Having to support ten application programs and a dozen printers, meant a system administrator had to deal with 120 drivers. So the development of unified interfaces between programs and printers became an urgent need.
The appearance of “Page Description Languages”, describing the graphical representation of ink and toner on sheets of paper (or other output devices, like monitors, photo typesetters, etc.) in a common way, was a move that filled a big gap.
One such development was PostScript® by Adobe. It meant that an application programmer could concentrate on making his program generate a PostScript® language description of his printable page, while printing device developers could focus on making their devices PostScript® literate.
Of course, over time, there came the development of other description methods. The most important competitors to PostScript® were PCL (“Print Control Language”, from Hewlett-Packard®), “ESC/P” (from Epson) and GDI (“Graphical Device Interface” from Microsoft®).
The appearance of these page description languages made life easier, and facilitated further development for everybody. Yet the fact that there still remained different, incompatible, and competing page description languages keeps life for users, administrators, developers and manufacturers difficult enough.
PostScript® is most heavily used in professional printing environments such as PrePress and printing service industries. In the UNIX® and Linux® domains, PostScript® is the predominant standard as a PDL. Here, nearly every program generates a PostScript® representation of its pages once you push the “Print” button. Let us look at a simple example of (hand-made) PostScript® code. The following listing describes two simple drawings:
Example 4.1. PostScript® Code
%!PS 100 100 moveto 0 50 rlineto 50 0 rlineto 0 -50 rlineto closepath .7 setgray fill % first box over; next 160 100 moveto 0 60 rlineto 45 10 rlineto 0 -40 rlineto closepath .2 setgray fill
This tells the imaginary PostScript® “pen” to draw a path of a certain shape, and then fill it with different shades of grey. The first part translates into more comprehensive English as “Go to coordinate (100,100), draw a line with length 50 upward; then one from there to the right, then down again, and finally close this part. Now fill the drawn shape with 70% darkness grey.”
Of course, PostScript® can be much more complicated than this simplistic example. It is a fully fledged programming language with many different operators and functions. You may even write PostScript® programs to compute the value of Pi, format a hard disk or write to a file. The main value and strength of PostScript® however lies in the field to describe the layout of graphical objects on a page: it also can scale, mirror, translate, transform, rotate and distort everything you can imagine on a piece of paper -- such as letters in different font representations, figures, shapes, shades, colours, lines, dots, raster...
A PostScript® file is a representation of one or more pages to be printed, in a relatively abstract way. Ideally, it is meant to describe the pages in a device-independent way. PostScript® is not directly “visible”; it only lives on hard disks and in RAM as a coded representation of future printouts.
What you see on a piece of paper is nearly always a “raster image”. Even if your brain suggests to you that your eyes see a line: take a good magnifying glass and you will discover lots of small dots... (One example to the contrary are lines that have been drawn by “pen plotters”). And that is the only thing that the “marking engines” of today's printers can put on paper: simple dots of different colours, size and resolution, to make up a complete “page image” composed of different bitmap patterns.
Different printers need the raster image prepared in different ways. Thinking about an inkjet device: depending on its resolution, the number of inks used (the very good ones need 7 different inks, while cheaper ones might only use 3), the number of available jets (some print heads have more than 100!) dispensing ink simultaneously, the “dithering algorithm” used, and many other things, the final raster format and transfer order to the marking engine is heavily dependent on the exact model used.
Back in the early life of the “Line Printer Daemon”, printers were machines that hammered rows of ASCII text mechanically on to long media, folded as a zig-zag paper snake, drawn from a cardboard box beneath the table... What a difference from today!
Before the final raster images are put on paper cut-sheets, they have to be calculated somehow out of their abstract PostScript® representation. This is a very computing-intensive process. It is called the “Raster Imaging Process”, more commonly “RIP”).
With PostScript® printers the RIP-ping is taken care of by the device itself. You just send the PostScript® file to it. The “Raster Imaging Processor” (also called the RIP) inside the printer is responsible (and specialized) to fulfill quite well this task of interpreting the PostScript®-page descriptions and put the raster image on paper.
Smaller PostScript® devices have a hardware-RIP built in; it is etched in silicon, on a special chip. Big professional printers often have their RIP implemented as a software-RIP inside a dedicated fast UNIX® run computer, often a Sun SPARC Solaris or a SGI™ IRIX® machine.
But what happens, if you are not lucky enough to have a PostScript® printer available?
You need to do the RIP-ing before you send the print data to the marking engine. You need to digest the PostScript® generated by your application on the host machine (the print client) itself. You need to know how the exact raster format of the target printer's marking engine must be composed.
In other words, as you can't rely on the printer to understand and interpret the PostScript® itself, the issue becomes quite a bit more complicated. You need software that tries to solve for you the issues involved.
This is exactly what the omnipresent ghostscript package is doing for many Linux®, *BSD and other UNIX® boxes that need to print to non-PostScript® printers: ghostscript is a PostScript® interpreter, a software RIP capable of running many different devices.
To produce rasterised bitmaps from PostScript® input, the concept of “filters” is used by ghostscript. There are many different filters in ghostscript, some of them specialised for a certain model of printer. ghostscript filterspecializedin devices have often been developed without the consent or support of the manufacturer concerned. Without access to the specifications and documentation, it was a very painstaking process to reverse engineer protocols and data formats.
Not all ghostscript filters work equally well for their printers. Yet, some of the newer ones, like the stp Filter of the Gimp Print project, produce excellent results leading to photographic quality on a par or even superior to their Microsoft® Windows® driver counterparts.
PostScript® is what most application programs produce for printing in UNIX® and Linux®. Filters are the true workhorses of any printing system there. Essentially they produce the right bitmaps from any PostScript® input for non-PostScript® target engines.
CUPS uses its own filters, though the filtering system is based on Ghostscript. Namely the pstoraster and the imagetoraster filters are directly derived from Ghostscript code. CUPS has reorganised and streamlined the whole mechanics of this legacy code and organised it into a few clear and distinct modules.
This next drawing (done with the help of Kivio) gives an overview of the filters and backends inside CUPS and how they fit together. The “flow” is from top to bottom. Backends are special filters: they don't convert date to a different format, but they send the ready files to the printer. There are different backends for different transfer protocols.
Besides the heavy part of the filtering task to generate a print-ready bitmap, any printing software needs to use a SPOOLing mechanism: this is to line up different jobs from different users for different printers and different filters and send them accordingly to the destinations. The printing daemon takes care of all this.
This daemon is keeping the house in order: it is also responsible for the job control: users should be allowed to cancel, stop, restart, etc. their jobs (but not other peoples's jobs) and so on.
Now that you know how a PostScript® language file (which describes the page layout in a largely device independent way) is transformed into a Raster Image, you might ask: “Well, there are different kinds of raster output devices: first they differ in their resolution; then there are the different paper sizes; it goes on with many finishing options (duplex prints, pamphlets, punched and stapled output with different sheets of coloured paper being drawn from different trays, etc.). How does this fit into our model of device-independent PostScript®?”
The answer comes with so called PostScript® Printer Description (PPD files. A PPD describes all the device dependent features which can be utilised by a certain printer model. It also contains the coded commands that must be used to call certain features of the device. But PPDs are not a closed book, they are simple ASCII text files.
PPDs were “invented” by Adobe to make it easy for manufacturers to implement their own features into PostScript® printers, and at the same time retain a standard way of doing so. PPDs are well documented and described by Adobe. Their specification is a de-facto open standard.
Remember, advanced PostScript® printing was originally only developed for use on Microsoft® Windows® and Apple Mac® systems. For a long time, all of the feature rich printing on modern devices was simply unavailable for Linux® and UNIX®. CUPS changes this decisively. CUPS is closely tied with PPDs, and therefore existing PPDs can be utilised to the full by all systems powered by CUPS.
Using PPDs, printer manufacturers were able to insert device-specific hardware features into their products, for features such as duplexing, stapling, punching, finishing, etc.. The printer drivers load this PPD just like an additional configuration file. Thus the printer driver learns about the available device options and how to call them; the driver also presents them in a GUI to the user. Through this mechanism you are still able to print “device-independent” PostScript® page description language files and specify device-dependent finishing options on top, which are added to the application-generated PostScript®.
PPDs originally were not used routinely in UNIX® and Linux® systems. The vendors providing those PPDs never intended them for anything other than the originally supported operating systems: Microsoft® Windows® and Mac® OS. Through its brilliant move to fully support and utilise the existing PPD specification, CUPS now gives the power to use all features of modern printers to users of Linux® and Linux®-like systems. KDEPrint makes its usage even more comfortable than the CUPS developers ever dreamed of.
CUPS can use original Windows® PPDs, distributed by the vendors in the case of PostScript® printers. Those normally don't cost any money, and they can be grabbed from any Windows® computer with an installed PostScript® driver for the model concerned, or from the disks provided with the printer. There are also several places on the web to download them.
Now you know how PostScript®-Printers can use PPDs. But what about non-PostScript® printers? CUPS has done a very good trick: by using the same format and data structure as the PostScript® Printer Descriptions (PPDs) in the PostScript® world, it can describe the available print job options for non-PostScript® printers just the same. For its own special purposes CUPS just added a few special options (namely the line which defines the filter to be used for further processing of the PostScript® file).
So, the developers could use the same software engine to parse the Printer Description Files for available options for all sorts of printers. Of course the CUPS developers could not rely on the non-PostScript® hardware manufacturers to suddenly develop PPDs. They had to do the difficult start themselves and write them from scratch. More than 1000 of these are available through the commercial version of CUPS, called ESP PrintPro.
Meanwhile there are a lot of CUPS-specific PPDs available. Even now those are in most cases not originating from the printer manufacturers, but from Free software developers. The CUPS folks proofed it, and others followed suit: where Linux® and UNIX® printing one or two years ago still was a kludge, it is now able to support a big range of printers, including 7-colour inkjets capable of pushing them to Photo Quality output.
You can get PPDs to be used with CUPS and non-PostScript® printers from different areas in the Web:
first, there is the repository at www.linuxprinting.org, which lets you generate a “CUPS-O-Matic”-PPD online for any printer that had been supported by traditional ghostscript printing already. This helps you to switch over to CUPS with little effort, if you wish so. If your printer was doing well with the traditional way of ghostscript printing, take CUPS-O-Matic to plug your driver into the CUPS system and you'll have the best of both worlds.
second, there are CUPS-PPDs for the more than 120 printer models, which are driven by the new universal stp driver. stp (stood originally for Stylus Photo) is now developed by the gimp-print project; it was started by Mike Sweet, the leading CUPS developer and is now available through gimp-print.sourceforge.net. This driver prints real Photo quality on many modern inkjets and can be configured to make 120 CUPS-PPDs along its own compilation. HP® Laser- and DeskJet, Epson® Stylus and Photo Colour models as well as some Canon® and Lexmark® are covered.
third, there is the commercial extension to CUPS from the CUPS developers themselves: it is called ESP PrintPro and comes with more than 2.300 printer drivers. There are even improved imagetoraster and pstoraster filters included.
CUPS makes it really easy for manufacturers to start supporting Linux® and UNIX® printing for their models at reasonably low cost. The modular framework of CUPS facilitates to plug in any filter (=driver) with minimal effort and to access and utilise the whole printing framework that CUPS is creating.
Read more about the exciting CUPS features in the available CUPS documentation at http://www.cups.org/documentation.html and http://www.danka.de/printpro/faq.html. Also at http://www.linuxprinting.org/ is a universal repository for all issues related to Linux® and UNIX® printing.
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For a long time many developers were deeply dissatisfied with good old LPD. Quite a few new projects were started to improve printing: LPRng is the best known example. Others are PDQ, PPR, PLP, GNUlpr and RLPR. But none of the new programs were seen as a “big shot”; most of them are just implementing the same old LPD specification with a few (or many) new extensions, which again make them incompatible with each other.
Having seen the development of not just one, but different viable alternatives to venerable BSD-style LPD, Grant Taylor, author of the Linux Printing HOWTO, finally rallied the call LPD Must Die! in his “Campaign To Abolish The Line Printer Daemon”.
Along with the above, on the industry side of things, there were efforts to overcome the well-known weaknesses of LPD. It started with proprietary extensions to plain old LPD, and stretched as far as Hewlett-Packard®'s attempt to establish HP® JetDirect as a new standard for a network printing protocol. The result were even more incompatibilities.
In the end, an initiative to define a new common industry and IETF standard took shape. The “Printer Working Group” or PWG, a loose aggregation of vendors in hardware, software, and operating systems, drafted the new “Internet Printing Protocol”, IPP. IPP v1.1 has now been approved by the IETF (Internet Engineering Task Force) as a proposed standard, and now enjoys the unanimous support throughout the industry in Europe, USA and Japan. Most current network printer models have now built in IPP support on top of traditional LPR/LPD or JetDirect Printing.
IPP promises to solve a lot of problems network administrators face. This trade normally deals with heterogeneous network environments and spends more than half of its working hours dealing with printing problems.
By creating a unified set of query functions for IPP enabled printers and servers, for transferring files and setting job-control attributes etc., IPP is destined to work across all operating system platforms. It's rollout however, will not happen overnight, as many legacy print devices will still be in use for many years to come. Therefore, in IPP there is a provision made for backwards compatibility of all IPP implementations. CUPS is proving the viability of IPP printing in all environments.
The most striking advantage will be it's integration into the existing set of other robust IP protocols. Being an extension of the proven and robust HTTP 1.1 protocol, for the special task of handling print file and related data, it is also very easy to plug in other standards as they are being developed and deployed:
Basic, Digest, and Certificate Authentication for users seeking access to print services.
SSL3 and TLS encryption for transferring data.
Bi directional communication of clients with print devices, using the HTTP/IPP GET and POST mechanism.
LDAP directory service integration to keep a consistent database of available printers, their capabilities and page-costs, etc., as well as user passwords, ACLs etc..
“Pull” (as opposed to the usual “Push” model) printing, where a server or printer just needs to be told the URL of a document, whereupon it is retrieved from the resource on the internet and printed.
Have you ever seen a demonstration about CUPS capabilities in the network? You must have been quite impressed if you didn't know in advance what to expect.
Imagine you as the administrator of a “LAN”. For testing purposes you fully installed one KDE/CUPS box on your net, complete with a dozen printers configured and functional: PostScript®, LaserJets, InkJets and BubbleJets, and so on. Your KDE users on that box are very happy, they can print like never before, “ringing all the bells and whistles” of every printer. It took you 2 hours to make everything run perfectly... and now all the other 100 users on the network want the same. Two hours again for every box? No way you could do that before next year, you think?
Wrong. Just change one setting in the original CUPS box to make it a “server”. Install CUPS on five other boxes, as “clients”. By the time you turn back to your first client, you find the users happily playing with the settings for the dozen printers you had defined earlier on the “server”. Somehow magically the printers had appeared on all the “Print” dialogues of the five new CUPS client boxes.
Your users print, but not a single driver had been installed on the clients, nor a printer queue defined.
So, how does this magic work?
The answer is not complicated at all.
If a CUPS server is on the LAN, it broadcasts the names of all available printers to the LAN, using the UDP protocol and port 631. Port 631 is reserved as a “well-known port” by IANA (the “Internet Assigning Numbers Authority”) for IPP purposes. All CUPS clients listen to CUPS server info sent to their port 631. That's how they know about available printers, and that's how they learn about the “path” to the printers as well.
Using IPP, which is really a clever extension to HTTP v1.1, CUPS is able to address all objects related to the printing system via “Universal Resource Locators” or URLs. Print jobs to be deleted or restarted, printers to be queried or modified, admin tasks to be performed on the server, with IPP and CUPS, everything is addressable by a certain URL. Many important things can be done through the web interface to CUPS, accessible for example with Konqueror.
And more, the clients basically can “administer” and “use” any printer they see, just as if it was a locally installed one. Of course, you can set restrictions on it with access control lists etc., so that not any clients may use any printer as it likes.
The clients even are able to print without the appropriate filter (or driver) installed locally.
So how does this work? If a client wants to know about and select printer-specific options, it sends a request (called CUPS-get-ppd) to the server. The server tells the client all about all printer-specific options, as read from the server side PPD. The user on the client side can see the options and select the required ones. He then sends the print file, usually unfiltered “raw” PostScript®, spiced up with the printer-options to the printer server, using IPP as the transport protocol. All further processing, especially the filtering to generate the final format for the target printer, is then done by the server. The server has the necessary programs (“drivers” or “filters”) to do this.
This way a client prints without needing to install a driver locally.
Any change on the server, such as adding or modifying a printer, is instantly “known” to the clients with no further configuration.
Some other advanced features built into CUPS are the capacity to do “load balancing”.
If you define the same printer queues on two or more different servers, the clients will send their jobs to the first responding or available server. This implies an automatic load balancing amongst servers. If you have to take one server off the network for maintenance, the others will just take over its tasks without the users even noticing the difference.
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This chapter of the KDEPrint Handbook will walk you through most of the configuration or selection options of KDEPrint. It will mainly deal with CUPS in this version, as the author is most familiar with it, and also because KDEPrint started off with supporting CUPS best. Later versions of the KDEPrint software and editions of this handbook will support and explore other printing systems more closely.
You need to define your print subsystem, before you are able to install any printer with the KDEPrint framework. There are two areas where you can define this: either in KControl (The Printing Manager section), or directly and “on the fly” from the print dialogue.
Navigate to ->->->. At the bottom you can see a button that lets you select which printing subsystem you want to use. In KDE 2.2 you can choose from the following alternatives:
CUPS (Common UNIX® Printing System)
Print through an external program (generic)
LPR (Standard BSD Print System)
Generic UNIX® LPD print system (the default)
RLPR environment (print to remote LPD servers from the command line)
Of course, the chosen system must be installed, and up and running on your box prior to your selection, or before it takes effect.
On it's first startup, KDEPrint will try an autodetection. This only works for:
CUPS, as it is checking first for a running CUPS daemon
LPD, as it is checking for a running LPD daemon, plus a printcap file.
The system you choose must be installed on your system prior to your selection. The author's personal recommendation is CUPS.
Once autodetected, chosen, or changed, the active print subsystem will take effect for all KDE applications. Different users may have different print subsystems in use, if those do exist on the computer and are compliant with each other. Their settings are stored in the kdeprintrc. This file is unique to every user, and is normally installed in $.HOME/.kde/share/config/kdeprintrc
This file is not intended to be directly editable, and all available options can be set from the KDEPrint GUI.
You may even select a different printer subsystem, on the fly, from the kprinter dialogue box.
Once you have chosen your preferred and installed print subsystem, you are ready to investigate, configure administer and work with this system through the KDEPrint framework.
Navigate to ->->->. In the right part of the window you will see at least 4 printers predefined. These are the virtual or special purpose printers, explained in section . You will probably see a toolbar with 13 icons at the top of the window, and at least 4 tabs in the lower half of the window, labelled Information, Jobs, Properties and Instances.
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Start the print server configuration (now that you have chosen CUPS, this is equivalent to the configuration of the CUPS daemon) by clicking on the appropriate button. You can find it by moving the mouse slowly over the buttons and reading the tooltips. It should be the 11th from the left , or third from the right; its icon is a wrench.
The CUPS Server Configuration window pops up. It gives you a structured view of all the settings that apply to the CUPS daemon. The configuration file for that daemon is normally located in /etc/cups/cupsd.conf. This is a plain ASCII file with a syntax similar to the configuration file of the Apache web server. It is a good idea to create a backup copy, just in case something goes wrong with the configuration through KDEPrint/CUPS Server Configuration dialogues:
cp /etc/cups/cupsd.conf /etc/cups/cupsd.conf.bakAs this graphical user interface to edit the configuration file is such a new feature, you should have the second chance of resorting to the original file. So back it up, please.
One very nice feature is the “Quick Help” available. If you click on the little question mark (What's this?) on your window title bar, you'll see the cursor changing its form. Now click on a cupsd configuration setting field to find out what it means and what your options are. In most cases you should understand the meaning immediately, otherwise turn to the excellent CUPS documentation. (If your CUPS Daemon is running, you have it online on your own host at http://localhost:631/documentation.html.
If CUPS is not running, but installed on your system you could find it in your own host's file system. The exact location depends on your operating system, but on Linux® the default is /usr/share/doc/cups/ or /usr/share/doc/cups/documentation.html.
For the best, most detailed and most recent information you should always refer to the original CUPS documentation. CUPS is, much like KDE in a rapid development process. There are constantly new features being added. New features might for times be only configurable by directly editing the configuration files. The KDEPrint GUI might not have caught up with CUPS development.
Just in case you want to look at the original configuration files of your CUPS system -- they are here:
These paths are based on the default installation. Your operating system may have installed them to a different prefix, for example, /usr/local/, but the hierarchy should still match that shown below.
/etc/cups/The folder with the configuration files
/etc/cups/cupsd.confThe configuration file for the CUPS daemon
/etc/cups/printers.confThe configuration file that contains the information about your locally installed printers.
/etc/cups/ppd/The folder with PPD files of your installed printers.
The following links only work if your CUPS daemon is up and running. To access all the original CUPS documentation, go to:
A page with all the links to the other documents.
Direct access to the CUPS Software Administrator Manual in HTML format.
Direct access to the CUPS Software Administrator Manual in PDF format.
The latest on line documentation from the CUPS web site.
The following links give you access to the same files (probably icons and graphics will be missing) even if your CUPS daemon is not up and running. You need, however, CUPS installed on your system. (Some distributions might place the files somewhere else -- you're on your own then to find out where...) To access all the original CUPS documentation, go to:
This documentation is available even when the CUPS daemon is not installed, although you may find images and icons are missing when you view the HTML files.
As noted above, the hierarchy below should be intact, but your operating system may have installed CUPS to a different location.
/usr/share/doc/cups/documentation.htmlA page with all the links to the other documents.
/usr/share/doc/cups/sam.htmlDirect access to the CUPS Software Administrator Manual in HTML format.
/usr/share/doc/cups/sam.pdfDirect access to the CUPS Software Administrator Manual in PDF format.
There are a few WebSites and Newsgroups discussing CUPS (and Linux® Printing in General) and giving help to newbies at:
The CUPS website.
LinuxPrinting.org, the home of the Linuxprinting HOWTO and the Linux® Printer Database
And finally, there will be a WebSite for KDEPrint and related documentation, at http://kdeprint.sourceforge.net/
In the next section I will step you through most of the configuration options of KDEPrint with CUPS.
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This section is not yet complete
Tree view, icon view and list view
The icons of the task bar
Different fonts for different printers
Different printer icons mean different things
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This is the Welcome Screen for your server configuration dialogues. Clicking onto one of the items of the tree view on left side of the screen opens the appropriate part of the configuration settings.
Every setting has a default value. The defaults let CUPS normally work as a fully functional client. The clients listen on TCP/IP Port 631 for infos broadcast by CUPS servers on the LAN. This information let the clients print immediately after receiving them, without installing any driver or configuring any printer on the clients.
To configure a CUPS server (which is broadcasting its service to the LAN) you need to change settings from the defaults.
The dialogue to configure the CUPS server: welcome screen.
The dialogue to configure the CUPS server: welcome screen
To select the default setting of any item just enable the checkbox on the right side of the screen. To set an item to a different value, disable the checkbox and then go on to do the setting you want on the left side of the screen.
The complete server configuration includes:
Network General Configuration
Each of these configuration items will be described in the following sections of the manual.
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The server general configuration is done on this screen. It includes:
Server name
Administrator's email
Server user
Server group
Remote user name
The tab window to configure the CUPS server general settings lets you the change the default values. Click on the little question mark and then on one of the fields to get a “Quick Help” about the meaning of the setting.
If you are unsure, leave alone and turn to the original CUPS documentation first. If your CUPS daemon is already running, it is readable from the Konqueror by pointing it to URL http://localhost:631/documentation.html.
There, first “make friends” with the Software Administrator Manual. Otherwise, for example, if the CUPS daemon is not running, try looking in your local file system, by default at /usr/share/doc/cups/ or /usr/share/doc/cups/documentation.html.
The hostname of your server, as advertised to the world. By default, CUPS will use the hostname of the system. To set the default server usd by clients, see the client.conf file.
For example, enter myhost.domain.com
This is the hostname that is reported to clients. Should you ever encounter strange problems in accessing the server, put here its IP address for troubleshooting. This way you eliminate any potential name resolution problems; and you can more easily nail the real problem down.
This is the email address to send all complaints or problems to. By default CUPS will use “root@hostname”.
For example, enter root@myhost.com.
Contrary to what the quickhelp suggests, it is also legal to send an email full of praise and enthusiasm about CUPS and KDEPrint to the server administrator.
The user the server runs under. Normally this must be lp, however you can configure things for another user if needed.
The server must be initially run as root to support the default IPP port of 631. It changes users whenever an external program is run.
Enter for example lp.
This is the UNIX® user account for filters and CGI programs to run under. CGI programs are responsible for showing you the nice web administration interface accessible via http://localhost:631/).
There is no need to set the User directive to root, so never do this, as it only involves dangers. Should anyone discover security vulnerabilities in one of the used file filters, printer drivers or CGI programs, he could remotely execute arbitrary commands on your system with root user privileges. Always use an unprivileged account for the server directive User.
The group the server runs under. Normally this must be sys, however you can configure things for another group as needed.
Enter for example sys.
The name of the user assigned to unauthenticated accesses from remote systems. By default remroot.
This name will appear in log files and in queries about the job owner etc., for all resources and locations of the CUPS server that are configured to allow access without authentication. Authenticated entries will carry the authenticated names.
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The server logging configuration is done on this screen. It includes:
Access log file setting
Error log file setting
Page log file setting
Log level setting
Max log file size setting
This is an important screen for you. Should you ever encounter problems: here is the place to set the Log level to “debug”, restart the CUPS daemon and then look at the Error log file defined here for entries that might give you an insight to the trouble.
This is where accesses to the server are logged. If this does not start with a leading /, then it is assumed to be relative to the server root.
You can also use the special name syslog to send the output to the syslog file or daemon.
Enter a path, for example /var/log/cups/acces_log
The format of this file is stored in the so-called “Common Log Format”. This way you can use programs such as Webalizer or any other Web access reporting tool to generate reports on the CUPS server activities.
To include the server name in the file name use a %s in the name. Example: /var/log/cups/access_log-%s
kurt@transmeta:~ >tail/var/log/cups/access_log127.0.0.1 - - [04/Aug/2001:20:11:39 +0100] "POST /printers/ HTTP/1.1" 200 109 127.0.0.1 - - [04/Aug/2001:20:11:39 +0100] "POST /admin/ HTTP/1.1" 401 0 127.0.0.1 - - [04/Aug/2001:20:11:39 +0100] "POST / HTTP/1.1" 200 210 127.0.0.1 - - [04/Aug/2001:20:11:39 +0100] "GET /ppd/DANKA_P450.ppd HTTP/1.1" 200 51021 127.0.0.1 - - [04/Aug/2001:20:11:39 +0100] "POST /jobs/ HTTP/1.1" 200 246 10.160.16.45 - - [04/Aug/2001:20:11:39 +0100] "GET /printers/DANKA_P450 HTTP/1.0" 200 0 127.0.0.1 - - [04/Aug/2001:20:11:39 +0100] "POST / HTTP/1.1" 200 80 127.0.0.1 - - [04/Aug/2001:20:11:39 +0100] "POST / HTTP/1.1" 200 139 10.160.16.45 - - [04/Aug/2001:20:11:40 +0100] "GET /cups.css HTTP/1.0" 200 198 127.0.0.1 - - [04/Aug/2001:20:11:40 +0100] "POST / HTTP/1.1" 200 139 10.160.16.45 - - [04/Aug/2001:20:11:39 +0100] "GET /printers/DANKA_P450 HTTP/1.0" 200 7319 10.160.16.45 - - [04/Aug/2001:20:11:40 +0100] "GET /images/title-logo.gif HTTP/1.0" 200 5729
You see a separate line for each single access, showing the IP address of the accessing client, date and time of access, method of access (POST or GET), the requested ressource, the HTTP version used by the client, status code and the number of transferred bytes. Status code 200 means successful-OK the 401 in the above example was an unauthorized access which was denied. For a detailed explanation of the log format go to the CUPS Software Administrator Manual.
If this does not start with a leading /, then it is assumed to be relative to the server root. The default setting is /var/log/cups/error_log.
You can also use the special name syslog to send the output to the syslog file or daemon.
Enter the path, for example /var/log/cups/error_log
The error log excerpt below shows you the part logged for printing the test page with the default setting of Log level to “info”. For an explanation of the Log Level setting see further below.
kurt@transmeta:~ >tail/var/log/cups/error_logI [04/Aug/2001:23:15:10 +0100] Job 213 queued on 'DANKA_P450' by 'root' I [04/Aug/2001:23:15:10 +0100] Started filter /usr/lib/cups/filter/pstops (PID 18891) for job 213. I [04/Aug/2001:23:15:10 +0100] Started backend /usr/lib/cups/backend/lpd (PID 18892) for job 213.
If this does not start with a leading / then it is assumed to be relative to the server root. The default is /var/log/cups/page_log
You can also use the special name syslog to send the output to the syslog file or daemon.
Enter the path, for example /var/log/cups/page_log
The page log file has a line for every single page of every job printed.
Here is what some entries look like:
kurt@transmeta:~ >tail/var/log/cups/page_logGIMP_print_stp_HP kdetest 201 [03/Aug/2001:03:18:03 +0100] 4 1 GIMP_print_stp_HP kdetest 201 [03/Aug/2001:03:18:03 +0100] 5 1 GIMP_print_stp_HP kdetest 202 [03/Aug/2001:11:46:49 +0100] 1 1 GIMP_print_stp_HP kdetest 203 [03/Aug/2001:11:46:54 +0100] 1 1 DANKA_infotec_P450 kurt 204 [04/Aug/2001:03:29:00 +0100] 1 33 DANKA_infotec_P450 kurt 204 [04/Aug/2001:03:29:00 +0100] 2 33 DANKA_infotec_P450 kurt 204 [04/Aug/2001:03:29:00 +0100] 3 33 DANKA_infotec_P450 kurt 204 [04/Aug/2001:03:29:00 +0100] 4 33 DANKA_infotec_P450 root 205 [04/Aug/2001:19:12:34 +0100] 1 14 DANKA_infotec_P450 root 206 [04/Aug/2001:19:15:20 +0100] 1 1
In this excerpt of the file you find information on the name of the printers (GIMP_print_stp_HP and DANKA_infotec_P450) used through this server, the user names (kdetest, kurt and root), the job-IDs (“201” to “205”), time of printing, page number inside the job and the number of copies for the pages. For example, job-ID 204 had 4 pages and 33 copies printed, job-ID 205 had 14 copies of just 1 page) .
CUPS is dependent (for its calculation of the number of pages in a job) on passing the PostScript® through the “pstops” filter. See the Kivio Flowchart on the CUPS filter architecture for an idea about were this filter fits into the whole printing process). More, pstops depends for the counting on a DSC conforming (DSC is Document Structuring Conventions, a standard defined by Adobe) to be sent by the client. In most cases this is working.
However, this page accounting does not work for any “raw” printer queues (as those, by definition, don't use any filtering on the CUPS host and are by-passing pstops.) Every job going through a “raw” queue is counted as a 1-page-job (with possibly multiple copies). This is especially true for all Jobs send from Microsoft® Windows® clients via Samba to the CUPS server, as those jobs are already arriving in the correct format for the printer, because the clients use the original printer driver.
I am still looking for someone who will write a nice CUPS page log analysing tool. It should generate a report with a graphical output similar to the Webalizer's access log reports. This way you could have nice statistics to be used for accounting about usage of printers, load dependent on daytime or weekday, users etc. Anyone?
This setting controls the number of messages logged to the error log file. It can be one of the following:
Log everything.
Log almost everything.
Log all requests and state changes.
Log errors and warnings.
Log only errors.
Log nothing.
If you need to troubleshoot (or if you want to study the inner workings of CUPS), set the log level to debug or debug2. Then the error_log will have a lot more entries (not just errors, but also informational entries).
You can use this to watch “live” what CUPS is doing when you send a print job. In a Konsole type:
kurt@transmeta:~ >tail-f-n100/var/log/cups/error_log
This will give you the last 100 lines (-n 100) of the file onto the screen and a “realtime” update (-f)of what is happening. The following listing shows the printing of a test page (some pieces have been cut off for space reasons... Try it yourself if you need more info):
I [04/Aug/2001:23:15:12 +0100] Job 214 queued on 'DANKA_P450' by 'root'
D [04/Aug/2001:23:15:12 +0100] StartJob(214, 08426fe0)
D [04/Aug/2001:23:15:12 +0100] StartJob() id = 214, file = 0/1
D [04/Aug/2001:23:15:12 +0100] job-sheets=none,none
D [04/Aug/2001:23:15:12 +0100] banner_page = 0
D [04/Aug/2001:23:15:12 +0100] StartJob: argv = "DANKA_P450","214","root","KDE Print Test",
[....]
D [04/Aug/2001:23:15:12 +0100] StartJob: envp = "PATH=/usr/lib/cups/filter:/bin:/usr/bin", [....]
D [04/Aug/2001:23:15:12 +0100] StartJob: statusfds = 5, 6
D [04/Aug/2001:23:15:12 +0100] StartJob: filterfds[1] = 7, -1
D [04/Aug/2001:23:15:12 +0100] StartJob: filter = "/usr/lib/cups/filter/pstops"
D [04/Aug/2001:23:15:12 +0100] StartJob: filterfds[0] = 8, 9
D [04/Aug/2001:23:15:12 +0100] start_process("/usr/lib/cups/filter/pstops", [....]
I [04/Aug/2001:23:15:12 +0100] Started filter /usr/lib/cups/filter/pstops (PID 18991) for job 214.
D [04/Aug/2001:23:15:12 +0100] StartJob: backend = "/usr/lib/cups/backend/lpd"
D [04/Aug/2001:23:15:12 +0100] StartJob: filterfds[1] = -1, 7
D [04/Aug/2001:23:15:12 +0100] start_process("/usr/lib/cups/backend/lpd", [....]
I [04/Aug/2001:23:15:12 +0100] Started backend /usr/lib/cups/backend/lpd (PID 18992) for job 214.
D [04/Aug/2001:23:15:12 +0100] Page = 595x842; 15,16 to 580,833 [....] The lines tagged “D” at the beginning are debug level entries, the ones tagged “I” are there in “info” level.
Controls the maximum size of each log file before they are rotated. Defaults to 1048576 (1 Mb). Set this to 0 to disable log rotation.
Enter an size in bytes, for example 1048576
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The dialogue to configure the CUPS server. Different folders are to be set here. Normally you don't need to change anything in this section. In case you play around with fancy (TrueType, PostScript® or other) fonts on your system, this qis the place to do the settings for using those fonts when printing. Server folder settings include:
Executables: where to find the server executables
Configuration: where to find the server configuration files
Data: where to find the server data files
Temporary files: where to put the server temporary print files
Temporary Requests: where to find the server
Font Path: where to find the server fonts
The root folder for the scheduler executables. By default this is /usr/lib/cups (or /usr/lib32/cups on IRIX 6.5)
The root folder for the scheduler. By default, /etc/cups.
On the authors SuSE system, this is /usr/share/doc/cups. It contains all the HTML or PDF documentation for CUPS which is available through the Web interface at http://localhost:631/documentation.html
The root folder for the CUPS data files. By default this is /usr/share/cups
It contains such things as banners, charsets, data, drivers, fonts, and pstoraster templates.
The folder to put temporary files in. This folder must be writable by the user defined on the previous screen. This defaults to either /var/spool/cups/tmp or the value of the TMPDIR environment variable.
The folder where request files are stored. By default this is /var/spool/cups
The place to configure the CUPS server for handling your fancy fonts (TrueType or PostScript®). CUPS will look here for fonts to embed in printfiles. This currently only affects the pstoraster filter, and the default is /usr/share/cups/fonts.
To specify more than one folder, list them with double colons as separator. Do it like this:
/path/to/first/fontdir/:/path/to/second/fontdir/:/path/to/last/fontdir/
For the Font path directive to work as intended, the application that wants to print needs to:
Either correctly reference its desired fonts in the header of the generated PostScript®
Or embed the font into the PostScript® file.
Referencing the font by name leaves it up to the RIP and print device to respect and actually use it. RIP or printer can only use the desired font, if it is available on the system.
In the case of a PostScript® printer, this needs to be a printer-resident font. If the printer doesn't have this font, it will try and replace it by an adequately similar font.
In the case of a non PostScript® printer, this is done by CUPS and its RIP-ing filtering system. CUPS will use the font path directive to grab the correct font when RIP-ing the PostScript® in the pstoraster filter.
In the case of a PostScript® output device, CUPS is just spooling the file (actually, it is passing it through the pstops filter for accounting or n-up purposes), not “working” on it. Therefore, if you print to a PostScript® printer it is solely the printer's responsibility to use the font asked for. It can't, if the font is neither loaded into the printer nor embedded in the PostScript®.
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The dialogue to configure the CUPS server HTTP settings is shown here.
CUPS server HTTP settings are the following ones:
the Document folder
the Default Language
the Default Charset
The root folder for HTTP documents that are served. By default the compiled in folder, /usr/share/cups/doc
The default language, if not specified by the browser. If not specified, the current locale is used.
Use the two letter locale codes, for example en or de.
The default character set to use. If not specified, this defaults to UTF-8. This can also be overridden directly in the HTML documents.
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This is the dialogue to configure the CUPS server security settings. The server encryption support settings are these:
Server certificate: the file to read containing the server's certificate
Server key: the file to read containing the server's key
The file to read containing the server's certificate. Defaults to /etc/cups/ssl/server.crt.
The file to read containing the server's key. Defaults to /etc/cups/ssl/server.key
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The dialogue to configure the CUPS server miscellaneous settings is shown here. The following server settings are done through this screen:
Preserve job history: whether to preserve a job history for later re-view
Preserve job files: whether to preserve fully RIP-ed job files for later re-print
Printcap file: setting the name of and the path to a printcap file
RIP Cache: setting the size of the RIP cache in memory
Filter Limit: defining a filter limit
Whether or not to preserve the job history after a job is completed, canceled, or stopped. The default is yes
Whether or not to preserve the job files after a job is completed, canceled, or stopped. The default is no.
The name of the printcap file. The default is no filename. Leave this blank, to disable printcap file generation.
The printcap setting is only needed to satisfy older applications in need of such a file.
The amount of memory that each RIP should use to cache bitmaps. The value can be any real number, followed by “k” for kilobytes, “m” for megabytes, “g”for gigabytes, or “t” for tiles, where one tile is 256 x 256 pixels. The default value is 8m.
Sets the maximum cost of all job filters that can be run at the same time. A limit of 0 means no limit. A typical job may need a filter limit of at least 200. Limits less than the minimum required by a job force a single job to be printed at any time. The default limit is 0 (unlimited).
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The dialogue to configure the CUPS server network settings is shown here. It includes:
Look for hostname on IP addresses
Port
Max request size
Timeout
Whether or not to do lookups on IP addresses to get a fully-qualified hostname. This defaults to off, for performance reasons.
Enter here Ports and addresses that the server will listen to. The default port 631 is reserved for the Internet Printing Protocol, and is what we use here.
You can have multiple entries, to listen to more than one port or address, or to restrict access.
Unfortunately, most web browsers don't support TLS or HTTP upgrades for encryption. If you want to support web-based encryption, you'll probably need to listen on port 443, the HTTPS port.
Use the and buttons to add and remove entries from the list.
You can enter ports on their own, e.g. 631, or hostnames with ports, e.g. myhost:80 or 1.2.3.4:631.
Controls the maximum size of HTTP requests and print files. The default setting is 0, which disables this feature.
The timeout (in seconds) before requests time out. The default is 300 seconds.
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The dialogue to configure the CUPS network client settings is shown here. It includes:
Accept "Keep Alive" requests
KeepAliveTimeout:
MaxClients:
Whether or not to support the Keep-Alive connection option. The default is on.
The timeout (in seconds) before Keep-Alive connections are automatically closed. The default is 60 seconds.
Controls the maximum number of simultaneous clients that will be handled. Defaults to 100.
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The dialogue to configure the CUPS browsing general settings is shown here. It includes:
Enable browsing
Use short names when possible
Use implicit classes
Whether or not to broadcast printer information to other CUPS servers. Enabled by default.
Whether or not to use “short” names for remote printers when possible (e.g. printer instead of printer@host). Enabled by default.
Whether or not to use implicit classes.
Printer classes can be specified explicitly, in the classes.conf file, implicitly based upon the printers available on the LAN, or both.
When Implicit classes are enabled, printers on the LAN with the same name (e.g. Acme-LaserPrint-1000) will be put into a class with the same name. This allows you to setup multiple redundant queues on a LAN without a lot of administrative difficulties. If a user sends a job to Acme-LaserPrint-1000, the job will go to the first available queue.
This option is enabled by default.
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The dialogue to configure the CUPS server browsing connection is shown here. Browsing connection settings include:
Broadcast addresses: The (UDP) broadcast address to transmit printer information to
Broadcast Port: The port number to use for broadcasting
Poll addresses: The address(es) to poll for information about printers on servers that might not broadcast (or whose broadcasts might not reach your LAN due to routers in between).
After pressing the button, you will see the following dialogue to enter a new value for outgoing broadcasting browse packets. It is the same kind of dialogue as for adding other CUPS server addresses to be polled for printer information.
This option specifies a broadcast address to be used. By default, browsing information is broadcast to all active interfaces.
HP-UX® 10.20 and earlier do not properly handle broadcast unless you have a Class A, B, C or D netmask (i.e., there is no CIDR support).
The port used for UDP broadcasts. By default this is the IPP port; if you change this, you need to do it on all servers. Only one BrowsePort is recognised.
Poll the named server(s) for printers.
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The dialogue to configure the CUPS server allowed and/or denied browse packets from other servers is shown here.
Browse allow:
Browse deny:
Browse order:
The dialogue to enter a new value for the address of another CUPS server to accept browse packets from is shown here. It is opened by clicking on the button beside the field named Browse Allow:. It is the same dialogue as for adding “denied” broadcast sending addresses.
The dialogue to enter a new value for the address of another CUPS server to accept browse packets from is shown here.
Browse allow specifies an address mask to allow for incoming browser packets. The default is to allow packets from all addresses.
Browse deny specifies an address mask to deny for incoming browser packets. The default is to deny packets from no addresses.
Both Browse allow and Browse deny accept the following notations for addresses:
All
None
*.domain.com
.domain.com
host.domain.com
nnn.*
nnn.nnn.*
nnn.nnn.nnn.*
nnn.nnn.nnn.nnn
nnn.nnn.nnn.nnn/mmm
nnn.nnn.nnn.nnn/mmm.mmm.mmm.mmm
The hostname/domain name restrictions will only work if you have turned hostname lookups on!
Specifies the order of the allow/deny comparisons.
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The dialogue to configure the CUPS server browse timeout settings is shown here. Browse timeout settings include:
Browse Interval
Browse Timeout
The time between browsing updates in seconds. The default is 30 seconds.
Note that browsing information is sent whenever a printer's state changes as well, so this represents the maximum time between updates.
Set this to 0 to disable outgoing broadcasts so your local printers are not advertised, but you can still see printers on other hosts.
The timeout (in seconds) for network printers - if we don't get an update within this time, the printer will be removed from the printer list.
This number definitely should not be less than the browse interval period, for obvious reasons. Defaults to 300 seconds.
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The dialogue to configure the CUPS server as a browsing relay is shown here. Browsing relay settings include:
Browser packets relay
The dialogue to enter a new value for an address pair to define browsing relaying between a CUPS server and a network is shown here.
Relay browser packets from one address or network to another.
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The dialogue to configure the CUPS server security settings for any of the defined server locations is shown here. It contains the following settings, which may be defined separately for any valid resource (or location) of the CUPS server:
System Group:
Access Permissions:
Auth Type:
Auth Class:
Auth Group Name:
Encryption:
Allow:
Deny:
Order:
Valid resources (or locations) of the CUPS server are:
Server Root Location: /
Server Administration Location: /admin
All printers on the server: /printers
Any individual printer on the server: e.g. /printers/infotec_P320
All printer classes on the server: /classes:
Any individual printer class on the server: e.g. /classes/all_infotecs_P320_or_P450
For all locations that are not defined separately the setting of the location “above” it is valid.
For example, you have a printer named infotec_P450 with no set security options. Then the security of the location /printers will take the responsibility for this printer as it is a sub-location of/printers. If, in turn there is no security set for /printers, then the security for / (the general security) of the server takes responsibility. Either you have set this for your purpose or the compiled-in default value takes over.
The group name for System or printer administration access. The default varies depending on the operating system, but will be sys, system or root (checked for in that order).
Access permissions for each folder served by the scheduler. Locations are relative to the document root.
The authorisation to use:
Perform no authentication.
Perform authentication using the HTTP Basic method.
Perform authentication using the HTTP Digest method.
Local certificate authentication can be substituted by the client for Basic or Digest, when connecting to the localhost interface.
The authorisation class. Currently only “Anonymous”, “User”, “System” (valid user belonging to the group set as system group), and “group” (valid user belonging to the specified group) are supported.
The group name for “Group” authorisation
Whether or not to use encryption. This depends on having the OpenSSL linked into the CUPS library and scheduler.
Possible values are:
Always use encryption (SSL)
Never use encryption.
Use TLS encryption upgrade.
Use encryption if the server requests it.
Allows access from the specified hostname, domain, IP address or network. Possible values are:
All
None
*.domain.com
.domain.com
host.domain.com
nnn.*
nnn.nnn.*
nnn.nnn.nnn.*
nnn.nnn.nnn.nnn
nnn.nnn.nnn.nnn/mmm
nnn.nnn.nnn.nnn/mmm.mmm.mmm.mmm
The host and domain address require that you enable hostname lookups, as described earlier.
Denies access from the specified hostname, domain, IP address or network. Possible values are:
All
None
*.domain.com
.domain.com
host.domain.com
nnn.*
nnn.nnn.*
nnn.nnn.nnn.*
nnn.nnn.nnn.nnn
nnn.nnn.nnn.nnn/mmm
nnn.nnn.nnn.nnn/mmm.mmm.mmm.mmm
The host and domain address require that you enable hostname lookups, as described earlier.
The order of the allow and deny processing.
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The dialogue to configure the CUPS server security settings is discussed here. We use the example to add security definitions other than the default ones for the resource named all printers. For the CUPS web server, this is the location you access through http://localhost:631/printers/ or (remotely) through http://cups.server.name:631/printers/
The first screenshot shows the general location for this setting. Select or a resource for which you want to decide about its security settings.
This dialogue is to add a new resource. It looks similar if you want to modify an already existing resource. Here are the general options:
.This is the second part or the dialogue is to add a new ressource. It looks similar if you want to modify an already existing resource. Here you define the actual access masks for the resource in question.
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Clicking on the leftmost icon on the toolbar 
in the upper part of the window starts the “Add Printer Wizard”.
This wizard steps you through various screens to install a new printer. At present this Wizard works for CUPS and the RLPR environment module. The number of steps depend on the actual print-subsystem which is active and available to you on your box.
Choose the “backend” protocol that CUPS is supposed to use with your new printer. There are:
local printer (serial, parallel, USB)
remote LPD queue
SMB shared printer (Windows®)
Network Printer (TCP, HP® JetDirect, AppSocket)
Network printer with IPP (IPP/HTTP)
File printer
serial fax /modem printer
Class of Printers
If some choices are greyed out, they are not available. For example, you may have no FAX backend software or no modem installed to use it.
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The contents of your next screen is dependent on your choice in the previous screen. If you know the details, just type them in to configure your network settings directly.
In other cases the wizard can scan the network for you, to help you decide which setting could be useful.
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If you use one of the network connections (remote LPD, SMB, remote CUPS, network printer with IPP), you have an option for scanning the network. Be careful when applying this; in some environments network scanning is considered to be hostile and harmful!
In the case of SMB, KDEPrint will use the Samba utilities nmblookup and smbclient (which need to be installed for this to work) to retrieve the information it presents in a tree structure.
In the case of IPP (Port 631) and TCP Network/AppSocket (Port 9100) KDEPrint will try to open the port and, if successful, send an ipp-get-printer-attribute request to the printer. For newer HP® printers the latter usually works, because they support both AppSocket and IPP.
Some printers or manufacturers use other port numbers for direct TCP/IP printing. You may need to look up which one to use. The Settings button in the dialogue lets you configure your scan, including IP addresses, ports and timeout to use.
Once again: be careful not to be mistaken for an intruder on your network, if you use the scanning technique.
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The hardest part is probably the “Printer Model Selection”. In former years the situation was difficult, because there were hardly any drivers to find. The difficulty now is there are too many; though some of them are very good, many are quite broken.
If you have a current “database” of available drivers on your system, select the manufacturer in the left part of the window first, then the device model in the right part. This split window shows all PPDs found by CUPS in its standard repository of installable PPDs. This repository normally is /usr/share/cups/model/. If you want your driver to be found automatically by CUPS and KDEPrint, place it in there.
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On the next screen you will see a description of the driver selected previously. This description is extracted from the actual PPD used.
For a real PostScript® printer never try to install a “Foomatic” or “Gimp-Print” PPD, even if it is offered. You won't be happy with it. Instead find the original PPD from the manufacturer, preferably the one written for Windows® NT and use it.
Some Linux® distributions have supplied for CUPS every possible combination of Ghostscript filters and “foomatic” PPD files they could find on the net. Many of these are quite useless; they were generated a year ago, when the people at www.linuxprinting.org began their first experiments with supplying third party PPDs for CUPS. Although dubbed “Alpha” at the time, these started to take on a life of their own and can now be found at various places on the net, doing CUPS no favours.
If you are not sure which ones to use go to:
And ask for help. At a later stage, a document detailing the differences between the different driver and PPD models will appear at http://kdeprint.sourceforge.net/ Watch out for this!
Via the button you are able to retrieve any PPD located somewhere on your available file system.
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Specify your first driver settings now. The most important one is the default paper size. In many cases this is set to “Letter”. If you live in an “A4” country and don't want your first test page to jam: now is the time to prevent this.
You are ready to start a test print. Hit the button.
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The last but one screen lets you select whether you want banners, and which ones you want to use, to mark the beginning and/or end of every printjob on that printer. You can also select and deselect banners before printing in the job options dialogues.
If you need to use custom banners, copy them into /usr/share/cups/banners/ to make them available for selection. They must be PostScript® files, however.
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The last screen lets you insert a name for your new printer.
The name must start with a letter and may contain numbers and underscores with a maximum size of 128 characters. Conform to this if you want to avoid erratic behaviour of your CUPS daemon. The printer names in CUPS are not case sensitive! This is a requirement of IPP. So the names DANKA_infotec, Danka_Infotec and danka_infotec all represent the same printer.
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This chapter gives you some hints about further configuration possibilities which may not be available through the KDEPrint GUI interface to CUPS.
All of the most often used features and functions CUPS provides are supported in KDEPrint.
Printer management is supported: add, remove, modify, configure, test, disable, enable ...
Job management is supported: cancel, hold, release, move to different printer
Print options: for full control as provided by CUPS.
A lot of information about the inner workings of CUPS is available through the web interface, which CUPS will always support. It works with any browser (yes, even text-based ones). Just go to http://localhost:631/ for a start. There you find a link to locally available CUPS documentation in HTML and PDF if you are new to CUPS.
CUPS is accessible through other means than KDEPrint: commandline and browser are two native CUPS interfaces. The many commandline utilities add up to the most complete control you have on CUPS. The web interface is only a subset of all available configuration or control options.
This is also true for KDEPrint. Generally, as CUPS develops, most new features will first be implemented through the commandline. Be sure to check the latest versions of the man pages for CUPS to stay up-to-date with new features after you install a new version.
Depending on your update method for CUPS, your active configuration file might not have been re-placed by a new one; thus your new, more capable CUPS-daemon might not have been told by the old configuration file about the new features to use.
A complete list of available files and man pages should always be in the CUPS Software Administrator Manual (http://localhost:631/sam.html#FILES. In the Konqueror URL/location field, type man:/lpadmin and man:/cupsd.conf to find out about the most important command and configuration file. You knew already about Konqueror's nice abilities to show you the traditional UNIX® man pages, didn't you? Read this. From there you find more interesting hints and links to other man pages and documentation.
Here is a way to find out which CUPS related man pages there are on your system:
kurt@transmeta:~ >aproposcupscups-calibrate (8)- ESP Printer Calibration Tool lpstat (1) - print cups status information cups-lpd (8) - receive print jobs + report printer status to lpd clients classes.conf (5) - class configuration file for cups backend (1) - cups backend transmission interfaces filter (1) - cups file conversion filter interfaces cups-polld (8) - cups printer polling daemon mime.types (5) - mime type description file for cups cupsd (8) - common unix printing system daemon lpadmin (8) - configure cups printers and classes cupsd.conf (5) - server configuration file for cups mime.convs (5) - mime type conversion file for cups printers.conf (5) - printer configuration file for cups mime.convs (5) - mime type conversion file for cups cups-polld (8) - cups printer polling daemon lpstat (1) - print cups status information backend (1) - cups backend transmission interfaces mime.types (5) - mime type description file for cups cupsd (8) - common unix printing system daemon lpadmin (8) - configure cups printers and classes printers.conf (5) - printer configuration file for cups cupsd.conf (5) - server configuration file for cups filter (1) - cups file conversion filter interfaces
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Here are a few examples of options that are presently only available if you use the commandline.
When installing (or modifying) a printer through the command line, you can either deny or allow the usage of that printer to certain users:
lpadmin -pHeidelbergDigimaster9110 -v lpd:/10.160.16.99/mqueue -u allow:kurt,sylvi,hansjoerg -E -P /home/kurt/PPDs/DVHV.ppdwill allow the usage of this (believe me: very nice and also very professional) printer to only the three mentioned users and at the same time deny it to all others. If another user wants to print on the DigiMaster via this CUPS server, he will receive an error message along the lines client-error-not-possible.
lpadmin -p HeidelbergDigimaster9110 -v lpd:/10.160.16.99/mqueue -u deny:tackat,boss,waba -E -P /home/kurt/PPDs/DVHV.ppdwill deny the usage of this same printer to the three mentioned users and at the same time allow it to all others. If “denied” user wants to print on the DigiMaster via this CUPS server, he will receive an error message along the lines client-error-not-possible.
Only one of the two options may be used at one time; at present there is no support to have a similar option in a per-group based way. This will be implemented in the future.
Sometimes you want to impose quotas for certain printers. With quotas you can set upper limits for the number of pages or the amount of data to be printed over a certain period to a certain printer.
Quotas can be set with the -o option when installing a printer with the lpadmin command, or afterwards for an already existing printer. Following are some guidelines (which are missing at the time of writing in the, official CUPS documentation):
With CUPS you may have pagecount- and filesize-based quotas for individual printers.
Quotas are calculated for each user individually (so a single set of limits applies to all users for the printer concerned).
Quotas include banner pages (if those are used).
This means: you can limit every user to 20 pages per day on an expensive printer, but you cannot limit every user except Kurt or root.
There are job-k-limit, job-page-limit, and job-quota-period options to give when setting up a printer.
job-quota-period sets a time interval for quota computing (intervals are determined in seconds; so a day is 60x60x24=86.400, a week is 60x60x24x7=604,800, and a month is 60x60x24x30=2.592.000 seconds.)
For quotas to be enforced, the time-period plus at least one job-limit must be set to non-zero.
The default value of 0 for job-k-limit specifies that there is no limit.
The default value of 0 for job-page-limit specifies that there is no limit.
The default value of 0 for job-quota-period specifies that the limits apply to all jobs that have been printed by a user that are still known to the system.
Working, as both, time-period plus one or both job-limits are defined
lpadmin -p danka_infotec_4850 -o job-quota-period=604800 -o job-k-limit=1024This sets a limit of a file size of 1 MB (in total) for each user of existing printer danka_infotec_4850 during one week.
lpadmin p danka_infotec_4105 -o job-quota-period=604800 -o job-page-limit=100This sets a limit of 100 pages (in total) for each user of existing printer danka_infotec_4105 during one week.
lpadmin -p danka_infotec_P450 -o job-quota-period=604800 -o job-k-limit=1024 -o job-page-limit=100This sets a combined limit of 1 MB (in total) and 100 pages (in total) for each user of existing printer danka_infotec_P450 during one week. Whichever limit is reached first will take effect.
NOT working, as only one, time-period or job-limit is defined)
lpadmin-pdanka_infotec_P320-ojob-quota-period=604800lpadmin-pdanka_infotec_FullColor-ojob-page-limit=100lpadmin-pdanka_infotec_HiSpeed-ojob-k-limit=1024
There are different ways to define a “raw” printer. One comfortable one is to use the lpadmin command. Just don't define a PPD file to be used for that printer and it will be a raw one:
lpadmin -p Raw_Danka_infotec -E -v lpd://10.160.16.137/PORT1Raw printer queues are those which don't touch the print file to transform it to a different file format. You need this for example when printing from Windows® clients via Samba through a CUPS server to a PCL printer: in this case the Windows® side printer driver would generate the finished print file format for the target printer and filtering it through CUPS filters would only harm the purpose. Under certain circumstances (if you want to make sure that the file goes to the printer “unfiltered” by CUPS) the “lpadmin without a PPD” comes in handy.
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This section of the KDEPrint Handbook will live from the readers' feedback. Here is just a small beginning.
No system is perfect. Here are some commonly seen traps people have fallen into.
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Printer management: basic operations are supported (add/remove/modify).
Each user can predefine the printers he wants to use by specifying the host and related printer queues. Printers are stored on a “per user basis”. This module is built around the rlpr utility rlpr
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Module used by default (on first start for example).
Generic module that only allows sending of print jobs. No printer or job management supported. It is made to work on a wide variety of UNIX® flavours: Linux®/LPR, HP-UX®, Solaris, IRIX®. It also supports some LPRng extensions (like the absence of continuation character \ in printcap files).
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Plain (old?) LPR support. An LPRng module is in development, and hopefully available for 2.3 release.
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An LPRng module for KDEPrint is in development, and hopefully available for the KDE 2.3 release.
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This module allows the print command to be specified completely (Netscape®-like). An edit line is added in the print dialogue for that purpose. Can be used in many cases, for example with a self-made print program.
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My employer is Danka Deutschland GmbH, a leading and manufacturer-independent provider of professional and hi-speed digital printing systems, black-and-white as well as colour. Danka provides hardware, software, service, maintenance, consumables and customised solutions for the products in its portfolio. I work there as a System Engineer. Amongst the brands Danka offers are Heidelberg (formerly Kodak), Canon, Hewlett-Packard®, Hitachi, Infotec and EfI.
My acquaintance with Linux® and the Free Software community is not too old. When I started to play around with Linux® at the beginning of 1999, my deepest disappointment was the poor support for printing. True, I made all our machines spit out simplex prints -- but what about duplex? What about punching the output? How to make sorting work? Or stapling, cover sheets and all the other beautiful finishing options our engines offer to customers? No way -- at least for me as a non-geek!
I began a search on the Internet for a solution. Fortunately not much later, in May 1999, Mike Sweet, principal developer of CUPS, announced the first Beta release of this superb piece of printing software. After trying it briefly, I knew this was it!
Next thing I attempted: to make Linux® distributions interested in this new stuff. Believe me -- it was more than tenacious! They seemed to think they already had the best thing they could get in printing. One reason probably was that they (and many Linux® developers) never had to think about how to best support a printer duplexer -- because one had never come near their own desks...
Finally, my attempts to make some Linux® print publications interested in CUPS “backfired” on me - one editor squeezed me into writing a series on the subject myself. And this is how some people started to give me the nickname “CUPS Evangelist”. I will not get rid of this nick anytime soon, now that even the KDE people wedged me into their timeframe of releases. Oh, boy...
Anyway, CUPS is now making its way around the world and it might well become a triumphal one: I am a little bit proud to have supported and contributed to this from near the beginning.
It should encourage you: even if some more experienced Linux® users than you are skeptical about it, and even if your programming skills are next to zero (like mine) - there are a lot of tasks and jobs and ideas, and talent that you can contribute to the Free Software community. Not least within the KDE project...
I'd like to thank...
Mike Sweet for developing CUPS in the first place
Jean-Eric Cuendet for starting kups and qtcups, the predecessors of KDEPrint
Michael Goffioul for doing all the hard work recently
Martin Konold for thinking twice
Sven Guckes for teaching me a few things about the art of “survival on the terminal” (just in case KDE is not there ;-) )
...too numerous others to mention who also let me snatch bits and bytes of knowledge off them
and last, but not least: Tom Schwaller for encouraging me to get into “documentation writing”
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KDEPrint has been developed on a system using CUPS 1.1.6. KDEPrint has been tested on other versions of CUPS and so far no incompatibilities are known. By the time of writing this Handbook, CUPS 1.1.9 is out with a few new features not yet supported by KDEPrint. Of course you are able to access these features, but you will need to bypass KDEPrint and use the CUPS command-line tools or edit configuration files manually. KDEPrint's development will go on and this Handbook strives to always be the best available user documentation resource for it.
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KDEPrint copyright 2001, Michael Goffioul (kdeprint AT swing.be)
This program is licensed under the terms of the GNU General Public License.
Documentation copyright 2001, Kurt Pfeifle, (kpfeifle AT danka.de)
This documentation is licensed under the terms of the GNU Free Documentation License.
Conversion to British English: Malcolm Hunter (malcolm.hunter AT gmx.co.uk)
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