[thirdparty/cups.git] / doc / help / overview.html

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<HEAD>
	<TITLE>Overview of CUPS</TITLE>
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<P>Printing within UNIX has historically been done using one of
two printing systems - the Berkeley Line Printer Daemon (LPD)
[RFC1179] and the AT&amp;T Line Printer system. These printing
systems were designed in the 70's for printing text to line
printers; vendors have since added varying levels of support for
other types of printers.</P>

<P>Replacements for these printing systems have emerged [LPRng,
Palladin, PLP], however none of the replacements change the
fundamental capabilities of these systems.</P>

<P>Over the years several attempts at developing a standard
printing interface have been made, including the draft POSIX
Printing standard developed by the Institute of Electrical and
Electronics Engineers, Inc. (IEEE) [IEEE-1387.4] and Internet
Printing Protocol (IPP) developed by the Internet Engineering
Task Force (IETF) through the Printer Working Group (PWG)
[IETF-IPP]. The POSIX printing standard defines a common set of
command-line tools as well as a C interface for printer
administration and print jobs, but has been shelved by the
IEEE.</P>

<P>The Internet Printing Protocol defines extensions to the
HyperText Transport Protocol 1.1 [RFC2616] to provide support
for remote printing services. IPP/1.1 was accepted by the IETF
as a proposed standard in ??? of ???. Unlike POSIX Printing, IPP
enjoys widespread industry support and has become the standard
network printing solution for all operating systems.</P>

<P>CUPS uses IPP/1.1 to provide a complete, modern printing
system for UNIX that can be extended to support new printers,
devices, and protocols while providing compatibility with
existing UNIX applications. CUPS is free software provided under
the terms of the GNU General Public License and GNU Library
General Public License.</P>

<H2 CLASS="title">History</H2>

<P>The first production release of CUPS (based on IPP/1.0) was
released in October of 1999. Version 1.1 of CUPS was released in
August of 2002 ???? and added support for IPP/1.1.</P>

<P>CUPS 1.2 is based on IPP/1.1 and adds many of the functional
enhancements that have been requested by our users. As with CUPS
1.1, CUPS 1.2 will be followed by patch releases that address
any problems found with the software. New features will be put
in the 1.3 release to follow.</P>

<H2 CLASS="title">Design Overview</H2>

<P>Like most printing systems, CUPS is designed around a central
print scheduling process that dispatches print jobs, processes
administrative commands, provides printer status information to
local and remote programs, and informs users as needed. Figure 1
shows the basic organization of CUPS.</P>

<P ALIGN="CENTER"><IMG SRC="../images/cups-block-diagram.gif"
WIDTH="470" HEIGHT="170" ALT="CUPS Block Diagram"/><BR>
<I>Figure 1 - CUPS Block Diagram</I></P>

<H3>Scheduler</H3>

<P>The scheduler is a HTTP/1.1 server application that handles
HTTP requests. Besides handling printer requests via IPP POST
requests, the scheduler also acts as a full-featured web server
for documentation, status monitoring, and administration.</P>

<P>The scheduler also manages a list of available printers on
the LAN and dispatches print jobs as needed using the
appropriate filters and backends.</P>

<H3>Configuration Files</H3>

<P>The configuration files consist of:</P>

<ul>

	<LI>The HTTP server configuration file.</LI>

	<LI>Printer and class definition files.</LI>

	<LI>MIME type and conversion rule files.</LI>

	<LI>PostScript Printer Description (PPD) files.</LI>

</ul>

<P>The HTTP server configuration file is purposely similar to
the Apache server configuration file and defines all of the
access control properties for the server.</P>

<P>The printer and class definition files list the available
printer queues and classes. Printer classes are collections of
printers. Jobs sent to a class are forwarded to the first
available printer in the class, round-robin fashion.</P>

<P>The MIME type files list the supported MIME types
(text/plain, application/postscript, etc.) and "magic' rules for
automatically detecting the format of a file.  These are used by
the HTTP server to determine the <tt>Content-Type</tt> field for
<tt>GET</tt> and <tt>HEAD</tt> requests and by the IPP request
handler to determine the file type when a <tt>Print-Job</tt> or
<tt>Send-File</tt> request is received with a
<tt>document-format</tt> of
<tt>application/octet-stream</tt>.</P>

<P>The MIME conversion rule files list the available filters.
The filters are used when a job is dispatched so that an
application can send a convenient file format to the printing
system which then converts the document into a printable format
as needed. Each filter has a relative cost associated with it,
and the filtering algorithm chooses the set of filters that will
convert the file to the needed format with the lowest total
"cost".</P>

<P>The PPD files describe the capabilities of all printers, not
just PostScript printers. There is one PPD file for each
printer. PPD files for non-PostScript printers define additional
filters through <tt>cupsFilter</tt> attributes to support
printer drivers.</P>

<H3>CUPS API</H3>

<P>The CUPS API contains CUPS-specific convenience functions for
queuing print jobs, getting printer information, accessing
resources via HTTP and IPP, and manipulating PPD files. Unlike
the rest of CUPS, the CUPS API is provided under the terms of
the GNU LGPL so it may be used by non-GPL applications.</P>

<H3>Berkeley and System V Commands</H3>

<P>CUPS provides the System V and Berkeley command-line
interfaces for submitting jobs and checking the printer status.
The <tt>lpstat</tt> and <tt>lpc status</tt> commands
also show network printers ("printer@server") when printer
browsing is enabled.</P>

<P>The System V administation commands are supplied for managing
printers and classes. The Berkeley printer administration tool
(<tt>lpc</tt>) is only supported in a "read-only' mode to
check the current status of the printer queues and
scheduler.</P>

<H3>Filters</H3>

<P>A filter program reads from the standard input or from a file
if a filename is supplied. All filters must support a common set
of options including printer name, job ID, username, job title,
number of copies, and job options. All output is sent to the
standard output.</P>

<P>Filters are provided for many file formats and include image
file and PostScript raster filters that support non-PostScript
printers. Multiple filters are run in parallel to produce the
required output format.</P>

<P>The PostScript raster filter is based on the ESP Ghostscript
core. Instead of using the Ghostscript printer drivers, the CUPS
filter uses a generic CUPS raster printer driver and
CUPS-compliant front-end to support any kind of raster printer.
This allows the same printer driver filter to be used for
printing raster data from any filter.</P>

<pre>Talk about Apple's use of CUPS...</pre>

<H3>CUPS Imaging</H3>

<P>The CUPS Imaging library provides functions for managing
large images, doing colorspace conversion and color management,
scaling images for printing, and managing raster page streams.
It is used by the CUPS image file filters, the PostScript RIP,
and all raster printers drivers.</P>

<H3>Backends</H3>

<P>A backend program is a special filter that sends print data
to a device or network connection. Backends for parallel,
serial, USB, LPD, IPP, and AppSocket (JetDirect) connections are
provided in CUPS 1.2.</P>

<P>SAMBA version 2.0.6 and higher includes a SMB backend
(<tt>smbspool(1)</tt>) that can be used for printing to
Windows.</P>

<H2 CLASS="title">Network Printing</H2>

<P>Traditionally, network printing has been one of the hardest
things to get working under UNIX. One reason is because each
vendor added their own extensions to the LPD protocol (the
previous standard for network printing), making cross-platform
printing difficult if not impossible.</P>

<P>Another reason is that you have to administer every network
printer on every client machine. In some cases you can "clone'
the printer configuration from a "master' client to each of the
others, but even that can be time-consuming and error-prone.
Something better is needed.</P>

<P>CUPS provides "printer browsing", which allows clients to
automatically see and use printers from any server on a LAN.
This means that you only need to configure the server and the
clients will automatically see the printers and classes on
it.</P>

<P>In addition, CUPS can automatically merge multiple identical
network printers into "implicit classes". This allows clients to
send jobs to the implicit class and have them print on the first
available printer or server. In addition, failsafe and
load-balancing functions are enabled simply by defining the same
printer on multiple servers!</P>

<H2 CLASS="title">New Features in CUPS 1.2</H2>

<P>CUPS 1.2 includes many new features and capabilities:

<ol>

	<LI><A HREF="#BACKENDS">Backends</A>

	<LI><A HREF="#BANNERS">Banner Page Support</A>

	<LI><A HREF="#DIGEST">Digest Authentication</A>

	<LI><A HREF="#DIRSVC">Directory Services</A>

	<LI><A HREF="#FHS2">Directory Structure Changes</A>

	<LI><A HREF="#DOCOS">Documentation</A>

	<LI><A HREF="#DRIVERS">Drivers</A>

	<LI><A HREF="#FILTERS">Filters</A>

	<LI><A HREF="#IPP">IPP Support</A>

	<LI><A HREF="#PERSISTENCE">Job Persistence</A>

	<LI><A HREF="#LPD">LPD Client Support</A>

	<LI><A HREF="#USEROPTS">User-Defined Printers and Options</A>

	<LI><A HREF="#WEB">Web Administration Interface</A>

</ol>

<H3><A NAME="BACKENDS">1. Backends</A></H3>

<P>CUPS 1.2 implements a new backend interface for retrieving a
list of available devices for CUPS clients. This allows
administration interfaces to query the CUPS scheduler for a list
of available devices, automatically configure printers if the
device identification information is available, and present the
user with a list of available devices rather than relying on the
user to know what devices are configured on the system.</P>

<P>The new release also includes a backend for USB printers
under *BSD and Linux. Support for USB under Solaris 8 will be
provided in a subsequent patch release.</P>

<H3><A NAME="BANNERS">2. Banner Page Support</A></H3>

<P>CUPS 1.2 includes support for banner pages at the beginning
and end of a job. Banner pages may be of any file format and
support variable substitution for job titles, usernames, etc.
Default banner pages are associated with each printer and can be
overridden with command-line options by the user.</P>

<H3><A NAME="DIGEST">3. Digest Authentication</A></H3>

<P>Digest authentication provides a more secure method of
authenticating access to the printing system. Unlike Basic
authentication, Digest authentication does not send passwords
"in the clear' so it is more difficult to gain unauthorized
access to your system.</P>

<P>CUPS 1.2 implements Digest authentication using a special MD5
password file instead of the UNIX password file. This file is
managed using the new <tt>lppasswd</tt> command.</P>

<H3><A NAME="DIRSVC">4. Directory Services</A></H3>

<P>CUPS 1.2 adds new directory service ("printer browsing")
features to make using CUPS on large LANs and WANs easier. You
can now poll a remote server for printer information and relay
it to the LAN as well as restrict what printer information is
processed (e.g. to "hide" servers, domains, or networks that you
don't want to see.)</P>

<H3><A NAME="FHS2">5. Directory Structure Changes</A></H3>

<P>CUPS 1.2 now uses a directory structure that complies with
the Filesystem Hierarchy Standard (FHS), version 2.0. This
should make integration into existing Linux and *BSD
distributions a lot easier.</P>

<H3><A NAME="DOCOS">6. Documentation</A></H3>

<P>The CUPS 1.2 documentation has gone through many revisions,
including a completely rewritten administrators manual, a new
programmers manual, and an IPP implementation reference
manual.</P>

<H3><A NAME="DRIVERS">7. Drivers</A></H3>

<P>CUPS 1.2 includes drivers for EPSON dot-matrix and inkjet
printers. As with the HP PCL drivers, the EPSON drivers don't
necessarily provide the best possible output for each printer
but should provide adequate printing quality for general
day-to-day printing.</P>

<H3><A NAME="FILTERS">8. Filters</A></H3>

<P>CUPS 1.2 includes new image, PostScript, PDF, and text
filters. The image filters have been upgraded to support Windows
BMP and Alias PIX files.</P>

<P>The PostScript filter is now based off ESP Ghostscript. The
new filter provides much better performance with
higher-resolution printers and supports all Level 3 PostScript
language features.</P>

<P>The new PDF filter is based off the excellent Xpdf software
from Derek Noonburg and supports automatic page scaling. The new
filter is a faster, smaller, more reliable replacement for the
GNU Ghostscript PDF filtering that was used in CUPS 1.0.</P>

<P>The new text filter now supports bidirectional text and can
embed fonts as needed.</P>

<H3><A NAME="IPP">9. IPP Support</A></H3>

<P>Probably the least visible portion of CUPS is the IPP
support. CUPS 1.1 implements all of the required IPP/1.1
operations and attributes and most of the optional ones. The
optional Create-Job and Send-File operations are now
implemented, allowing for better System V printing system
compatibility (one job ID per <tt>lp</tt> command) and support
for banner pages.</P>

<H3><A NAME="PERSISTENCE">10. Job Persistence</A></H3>

<P>CUPS 1.2 supports job persistence. This means that jobs are
preserved even after a reboot, a feature that was sorely missing
from CUPS 1.0.</P>

<P>In addition, CUPS 1.2 allows you to keep job information
after the job has printed. The basic post-job persistence mode
provides a job history (number of pages printed, time job was
printed, etc.) but does not preserve the actual job files. This
can be changed to discard all information after a job is printed
or keep the job files after printing so you can reprint a job at
some later time.</P>

<H3><A NAME="LPD">11. LPD Client Support</A></H3>

<P>By popular request, CUPS 1.2 supports LPD-based clients using
a new mini-daemon that handles LPD requests and passes them on
to the main server.</P>

<H3><A NAME="USEROPTS">12. User-Defined Printers and Options</A></H3>

<P>CUPS 1.2 includes support for user-defined printers and
options via a new <tt>lpoptions</tt> command. User-defined
printers are special instances of the available printers (e.g.
"printer/instance" or "printer@server/instance") that can have
their own default options such as media size, resolution, and so
forth. The <tt>lpoptions</tt> command can also be used to set a
different default printer queue.</P>

<H3><A NAME="WEB">13. Web Administration Interface</A></H3>

<P>CUPS 1.0 provided a simple class, job, and printer monitoring
interface for web browsers. CUPS 1.2 replaces this interface
with an enhanced administration interface that allows you to
add, modify, delete, configure, and control classes, jobs, and
printers.</P>

<H2 CLASS="title">Software Using CUPS</H2>

<P>A lot has happened since CUPS 1.0 came out, and many software
packages are supporting CUPS. We have contributed code to the
SAMBA team to support CUPS, and parts of that are already
available in SAMBA 2.0.6 and 2.0.7. With any luck the final
pieces that provide a complete integration with SAMBA will be
available in the next release of SAMBA.</P>

<P>Two graphical interfaces have appeared on the scene that use
CUPS as well. The KUPS project provides a KDE-based interface
for CUPS and can be found at:</P>

<pre>
    <A HREF="http://kups.sourceforge.net">http://kups.sourceforge.net</A>
</pre>

<P>The X Printing Panel (XPP) project provides a graphical
printing panel for CUPS and can be found at:</P>

<pre>
    <A HREF="http://www.phy.uni-bayreuth.de/till/xpp">http://www.phy.uni-bayreuth.de/till/xpp/</A>
</pre>

<P>Numerous other filters, drivers, tutorials, etc. have been
made available on the CUPS Links web page, available at:</P>

<pre>
    <A HREF="http://www.cups.org/links.php">http://www.cups.org/links.php</A>
</pre>

<P>Finally, our own ESP Print Pro software uses CUPS to provide
drivers for thousands of printers and can be found at:</P>

<pre>
    <A HREF="http://www.easysw.com/printpro">http://www.easysw.com/printpro</A>
</pre>

<H2 CLASS="title">Operating Systems Using CUPS</H2>

<P>One of our goals has always been to get as many UNIX/Linux
distributions using CUPS as possible. Debian is currently
providing CUPS as part of its stable distribution, and many
other distributions are considering it in their next
releases.</P>

<H2 CLASS="title">Summary</H2>

<P>The Common UNIX Printing System provides a modern printing
interface for UNIX applications that is both flexible and
user-friendly. The software provides System V and Berkeley
compatible command-line interfaces to ensure compatibility with
existing applications. CUPS 1.2 adds many new features that make
it an even better choice for printing under UNIX.</P>

<H2 CLASS="title">Who to Contact</H2>

<P>For more information on CUPS please contact us at:

<pre>
    Attn: CUPS Information
    Easy Software Products
    44141 Airport View Drive Suite 204
    Hollywood, Maryland 20636-3142 USA

    +1.301.373.9600

    <A HREF="mailto:cups-info@cups.org">cups-info@cups.org</A>
</pre>

<H2 CLASS="title">References</H2>

<DL>

	<DT>IEEE-1387.4</DT>

	<DD>System Administration - Part 4: Printing Interfaces
	(draft)</DD>

	<DT><A HREF="http://www.pwg.org/ipp/index.html">IETF-IPP</A></DT>

	<DD>Internet Printing Protocol/1.1</DD>

	<DT><A HREF="http://www.astart.com/lprng.html">LPRng</A></DT>

	<DD>An enhanced, extended, and portable implementation
	of the Berkeley LPR print spooler functionality</DD>

	<DT>Palladin</DT>

	<DD>A printing system developed at the Massachussetts
	Institute of Technology</DD>

	<DT><A HREF="http://www-usa.iona.com//hyplan/jmason/plp.html">PLP</A></DT>

	<DD>The Portable Line Printer spooler system</DD>

	<DT><A HREF="http://www.ietf.org/rfc/rfc1179.txt">RFC1179</A></DT>

	<DD>Line Printer Daemon Protocol</DD>

	<DT><A HREF="http://www.ietf.org/rfc/rfc2046.txt">RFC2046</A></DT>

	<DD>Multipurpose Internet Mail Extensions (MIME) Part
	Two: Media Types</DD>

	<DT><A HREF="http://www.ietf.org/rfc/rfc2616.txt">RFC2616</A></DT>

	<DD>Hypertext Transfer Protocol -- HTTP/1.1</DD>

</DL>

<H2 CLASS="title">Trademarks</H2>

<P>The Common UNIX Printing System, CUPS, and the CUPS logo are
the trademark property of Easy Software Products. All other
trademarks are the property of their respective owners.</P>

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</HTML>
Commit	Line	Data
ef416fc2	1	<HTML>
	2	<!-- SECTION: Getting Started -->
	3	<HEAD>
	4	<TITLE>Overview of CUPS</TITLE>
	5	</HEAD>
	6	<BODY>
	7
	8	<P>Printing within UNIX has historically been done using one of
	9	two printing systems - the Berkeley Line Printer Daemon (LPD)
	10	[RFC1179] and the AT&T Line Printer system. These printing
	11	systems were designed in the 70's for printing text to line
	12	printers; vendors have since added varying levels of support for
	13	other types of printers.</P>
	14
	15	<P>Replacements for these printing systems have emerged [LPRng,
	16	Palladin, PLP], however none of the replacements change the
	17	fundamental capabilities of these systems.</P>
	18
	19	<P>Over the years several attempts at developing a standard
	20	printing interface have been made, including the draft POSIX
	21	Printing standard developed by the Institute of Electrical and
	22	Electronics Engineers, Inc. (IEEE) [IEEE-1387.4] and Internet
	23	Printing Protocol (IPP) developed by the Internet Engineering
	24	Task Force (IETF) through the Printer Working Group (PWG)
	25	[IETF-IPP]. The POSIX printing standard defines a common set of
	26	command-line tools as well as a C interface for printer
	27	administration and print jobs, but has been shelved by the
	28	IEEE.</P>
	29
	30	<P>The Internet Printing Protocol defines extensions to the
	31	HyperText Transport Protocol 1.1 [RFC2616] to provide support
	32	for remote printing services. IPP/1.1 was accepted by the IETF
	33	as a proposed standard in ??? of ???. Unlike POSIX Printing, IPP
	34	enjoys widespread industry support and has become the standard
	35	network printing solution for all operating systems.</P>
	36
	37	<P>CUPS uses IPP/1.1 to provide a complete, modern printing
	38	system for UNIX that can be extended to support new printers,
	39	devices, and protocols while providing compatibility with
	40	existing UNIX applications. CUPS is free software provided under
	41	the terms of the GNU General Public License and GNU Library
	42	General Public License.</P>
	43
	44	<H2 CLASS="title">History</H2>
	45
	46	<P>The first production release of CUPS (based on IPP/1.0) was
	47	released in October of 1999. Version 1.1 of CUPS was released in
	48	August of 2002 ???? and added support for IPP/1.1.</P>
	49
	50	<P>CUPS 1.2 is based on IPP/1.1 and adds many of the functional
	51	enhancements that have been requested by our users. As with CUPS
	52	1.1, CUPS 1.2 will be followed by patch releases that address
	53	any problems found with the software. New features will be put
	54	in the 1.3 release to follow.</P>
	55
	56	<H2 CLASS="title">Design Overview</H2>
	57
	58	<P>Like most printing systems, CUPS is designed around a central
	59	print scheduling process that dispatches print jobs, processes
	60	administrative commands, provides printer status information to
	61	local and remote programs, and informs users as needed. Figure 1
	62	shows the basic organization of CUPS.</P>
	63
	64	<P ALIGN="CENTER"><IMG SRC="../images/cups-block-diagram.gif"
65	WIDTH="470" HEIGHT="170" ALT="CUPS Block Diagram"/><BR>
66	<I>Figure 1 - CUPS Block Diagram</I></P>
67
68	<H3>Scheduler</H3>
69
70	<P>The scheduler is a HTTP/1.1 server application that handles
71	HTTP requests. Besides handling printer requests via IPP POST
72	requests, the scheduler also acts as a full-featured web server
73	for documentation, status monitoring, and administration.</P>
74
75	<P>The scheduler also manages a list of available printers on
76	the LAN and dispatches print jobs as needed using the
77	appropriate filters and backends.</P>
78
79	<H3>Configuration Files</H3>
80
81	<P>The configuration files consist of:</P>
82
83	<ul>
84
85	<LI>The HTTP server configuration file.</LI>
86
87	<LI>Printer and class definition files.</LI>
88
89	<LI>MIME type and conversion rule files.</LI>
90
91	<LI>PostScript Printer Description (PPD) files.</LI>
92
93	</ul>
94
95	<P>The HTTP server configuration file is purposely similar to
96	the Apache server configuration file and defines all of the
97	access control properties for the server.</P>
98
99	<P>The printer and class definition files list the available
100	printer queues and classes. Printer classes are collections of
101	printers. Jobs sent to a class are forwarded to the first
102	available printer in the class, round-robin fashion.</P>
103
104	<P>The MIME type files list the supported MIME types
105	(text/plain, application/postscript, etc.) and "magic' rules for
106	automatically detecting the format of a file. These are used by
107	the HTTP server to determine the <tt>Content-Type</tt> field for
108	<tt>GET</tt> and <tt>HEAD</tt> requests and by the IPP request
109	handler to determine the file type when a <tt>Print-Job</tt> or
110	<tt>Send-File</tt> request is received with a
111	<tt>document-format</tt> of
112	<tt>application/octet-stream</tt>.</P>
113
114	<P>The MIME conversion rule files list the available filters.
115	The filters are used when a job is dispatched so that an
116	application can send a convenient file format to the printing
117	system which then converts the document into a printable format
118	as needed. Each filter has a relative cost associated with it,
119	and the filtering algorithm chooses the set of filters that will
120	convert the file to the needed format with the lowest total
121	"cost".</P>
122
123	<P>The PPD files describe the capabilities of all printers, not
124	just PostScript printers. There is one PPD file for each
125	printer. PPD files for non-PostScript printers define additional
126	filters through <tt>cupsFilter</tt> attributes to support
127	printer drivers.</P>
128
129	<H3>CUPS API</H3>
130
131	<P>The CUPS API contains CUPS-specific convenience functions for
132	queuing print jobs, getting printer information, accessing
133	resources via HTTP and IPP, and manipulating PPD files. Unlike
134	the rest of CUPS, the CUPS API is provided under the terms of
135	the GNU LGPL so it may be used by non-GPL applications.</P>
136
137	<H3>Berkeley and System V Commands</H3>
138
139	<P>CUPS provides the System V and Berkeley command-line
140	interfaces for submitting jobs and checking the printer status.
141	The <tt>lpstat</tt> and <tt>lpc status</tt> commands
142	also show network printers ("printer@server") when printer
143	browsing is enabled.</P>
144
145	<P>The System V administation commands are supplied for managing
146	printers and classes. The Berkeley printer administration tool
147	(<tt>lpc</tt>) is only supported in a "read-only' mode to
148	check the current status of the printer queues and
149	scheduler.</P>
150
151	<H3>Filters</H3>
152
153	<P>A filter program reads from the standard input or from a file
154	if a filename is supplied. All filters must support a common set
155	of options including printer name, job ID, username, job title,
156	number of copies, and job options. All output is sent to the
157	standard output.</P>
158
159	<P>Filters are provided for many file formats and include image
160	file and PostScript raster filters that support non-PostScript
161	printers. Multiple filters are run in parallel to produce the
162	required output format.</P>
163
164	<P>The PostScript raster filter is based on the ESP Ghostscript
165	core. Instead of using the Ghostscript printer drivers, the CUPS
166	filter uses a generic CUPS raster printer driver and
167	CUPS-compliant front-end to support any kind of raster printer.
168	This allows the same printer driver filter to be used for
169	printing raster data from any filter.</P>
170
171	<pre>Talk about Apple's use of CUPS...</pre>
172
173	<H3>CUPS Imaging</H3>
174
175	<P>The CUPS Imaging library provides functions for managing
176	large images, doing colorspace conversion and color management,
177	scaling images for printing, and managing raster page streams.
178	It is used by the CUPS image file filters, the PostScript RIP,
179	and all raster printers drivers.</P>
180
181	<H3>Backends</H3>
182
183	<P>A backend program is a special filter that sends print data
184	to a device or network connection. Backends for parallel,
185	serial, USB, LPD, IPP, and AppSocket (JetDirect) connections are
186	provided in CUPS 1.2.</P>
187
188	<P>SAMBA version 2.0.6 and higher includes a SMB backend
189	(<tt>smbspool(1)</tt>) that can be used for printing to
190	Windows.</P>
191
192	<H2 CLASS="title">Network Printing</H2>
193
194	<P>Traditionally, network printing has been one of the hardest
195	things to get working under UNIX. One reason is because each
196	vendor added their own extensions to the LPD protocol (the
197	previous standard for network printing), making cross-platform
198	printing difficult if not impossible.</P>
199
200	<P>Another reason is that you have to administer every network
201	printer on every client machine. In some cases you can "clone'
202	the printer configuration from a "master' client to each of the
203	others, but even that can be time-consuming and error-prone.
204	Something better is needed.</P>
205
206	<P>CUPS provides "printer browsing", which allows clients to
207	automatically see and use printers from any server on a LAN.
208	This means that you only need to configure the server and the
209	clients will automatically see the printers and classes on
210	it.</P>
211
212	<P>In addition, CUPS can automatically merge multiple identical
213	network printers into "implicit classes". This allows clients to
214	send jobs to the implicit class and have them print on the first
215	available printer or server. In addition, failsafe and
216	load-balancing functions are enabled simply by defining the same
217	printer on multiple servers!</P>
218
219	<H2 CLASS="title">New Features in CUPS 1.2</H2>
220
221	<P>CUPS 1.2 includes many new features and capabilities:
222
223	<ol>
224
225	<LI><A HREF="#BACKENDS">Backends</A>
226
227	<LI><A HREF="#BANNERS">Banner Page Support</A>
228
229	<LI><A HREF="#DIGEST">Digest Authentication</A>
230
231	<LI><A HREF="#DIRSVC">Directory Services</A>
232
233	<LI><A HREF="#FHS2">Directory Structure Changes</A>
234
235	<LI><A HREF="#DOCOS">Documentation</A>
236
237	<LI><A HREF="#DRIVERS">Drivers</A>
238
239	<LI><A HREF="#FILTERS">Filters</A>
240
241	<LI><A HREF="#IPP">IPP Support</A>
242
243	<LI><A HREF="#PERSISTENCE">Job Persistence</A>
244
245	<LI><A HREF="#LPD">LPD Client Support</A>
246
247	<LI><A HREF="#USEROPTS">User-Defined Printers and Options</A>
248
249	<LI><A HREF="#WEB">Web Administration Interface</A>
250
251	</ol>
252
253	<H3><A NAME="BACKENDS">1. Backends</A></H3>
254
255	<P>CUPS 1.2 implements a new backend interface for retrieving a
256	list of available devices for CUPS clients. This allows
257	administration interfaces to query the CUPS scheduler for a list
258	of available devices, automatically configure printers if the
259	device identification information is available, and present the
260	user with a list of available devices rather than relying on the
261	user to know what devices are configured on the system.</P>
262
263	<P>The new release also includes a backend for USB printers
264	under *BSD and Linux. Support for USB under Solaris 8 will be
265	provided in a subsequent patch release.</P>
266
267	<H3><A NAME="BANNERS">2. Banner Page Support</A></H3>
268
269	<P>CUPS 1.2 includes support for banner pages at the beginning
270	and end of a job. Banner pages may be of any file format and
271	support variable substitution for job titles, usernames, etc.
272	Default banner pages are associated with each printer and can be
273	overridden with command-line options by the user.</P>
274
275	<H3><A NAME="DIGEST">3. Digest Authentication</A></H3>
276
277	<P>Digest authentication provides a more secure method of
278	authenticating access to the printing system. Unlike Basic
279	authentication, Digest authentication does not send passwords
280	"in the clear' so it is more difficult to gain unauthorized
281	access to your system.</P>
282
283	<P>CUPS 1.2 implements Digest authentication using a special MD5
284	password file instead of the UNIX password file. This file is
285	managed using the new <tt>lppasswd</tt> command.</P>
286
287	<H3><A NAME="DIRSVC">4. Directory Services</A></H3>
288
289	<P>CUPS 1.2 adds new directory service ("printer browsing")
290	features to make using CUPS on large LANs and WANs easier. You
291	can now poll a remote server for printer information and relay
292	it to the LAN as well as restrict what printer information is
293	processed (e.g. to "hide" servers, domains, or networks that you
294	don't want to see.)</P>
295
296	<H3><A NAME="FHS2">5. Directory Structure Changes</A></H3>
297
298	<P>CUPS 1.2 now uses a directory structure that complies with
299	the Filesystem Hierarchy Standard (FHS), version 2.0. This
300	should make integration into existing Linux and *BSD
301	distributions a lot easier.</P>
302
303	<H3><A NAME="DOCOS">6. Documentation</A></H3>
304
305	<P>The CUPS 1.2 documentation has gone through many revisions,
306	including a completely rewritten administrators manual, a new
307	programmers manual, and an IPP implementation reference
308	manual.</P>
309
310	<H3><A NAME="DRIVERS">7. Drivers</A></H3>
311
312	<P>CUPS 1.2 includes drivers for EPSON dot-matrix and inkjet
313	printers. As with the HP PCL drivers, the EPSON drivers don't
314	necessarily provide the best possible output for each printer
315	but should provide adequate printing quality for general
316	day-to-day printing.</P>
317
318	<H3><A NAME="FILTERS">8. Filters</A></H3>
319
320	<P>CUPS 1.2 includes new image, PostScript, PDF, and text
321	filters. The image filters have been upgraded to support Windows
322	BMP and Alias PIX files.</P>
323
324	<P>The PostScript filter is now based off ESP Ghostscript. The
325	new filter provides much better performance with
326	higher-resolution printers and supports all Level 3 PostScript
327	language features.</P>
328
329	<P>The new PDF filter is based off the excellent Xpdf software
330	from Derek Noonburg and supports automatic page scaling. The new
331	filter is a faster, smaller, more reliable replacement for the
332	GNU Ghostscript PDF filtering that was used in CUPS 1.0.</P>
333
334	<P>The new text filter now supports bidirectional text and can
335	embed fonts as needed.</P>
336
337	<H3><A NAME="IPP">9. IPP Support</A></H3>
338
339	<P>Probably the least visible portion of CUPS is the IPP
340	support. CUPS 1.1 implements all of the required IPP/1.1
341	operations and attributes and most of the optional ones. The
342	optional Create-Job and Send-File operations are now
343	implemented, allowing for better System V printing system
344	compatibility (one job ID per <tt>lp</tt> command) and support
345	for banner pages.</P>
346
347	<H3><A NAME="PERSISTENCE">10. Job Persistence</A></H3>
348
349	<P>CUPS 1.2 supports job persistence. This means that jobs are
350	preserved even after a reboot, a feature that was sorely missing
351	from CUPS 1.0.</P>
352
353	<P>In addition, CUPS 1.2 allows you to keep job information
354	after the job has printed. The basic post-job persistence mode
355	provides a job history (number of pages printed, time job was
356	printed, etc.) but does not preserve the actual job files. This
357	can be changed to discard all information after a job is printed
358	or keep the job files after printing so you can reprint a job at
359	some later time.</P>
360
361	<H3><A NAME="LPD">11. LPD Client Support</A></H3>
362
363	<P>By popular request, CUPS 1.2 supports LPD-based clients using
364	a new mini-daemon that handles LPD requests and passes them on
365	to the main server.</P>
366
367	<H3><A NAME="USEROPTS">12. User-Defined Printers and Options</A></H3>
368
369	<P>CUPS 1.2 includes support for user-defined printers and
370	options via a new <tt>lpoptions</tt> command. User-defined
371	printers are special instances of the available printers (e.g.
372	"printer/instance" or "printer@server/instance") that can have
373	their own default options such as media size, resolution, and so
374	forth. The <tt>lpoptions</tt> command can also be used to set a
375	different default printer queue.</P>
376
377	<H3><A NAME="WEB">13. Web Administration Interface</A></H3>
378
379	<P>CUPS 1.0 provided a simple class, job, and printer monitoring
380	interface for web browsers. CUPS 1.2 replaces this interface
381	with an enhanced administration interface that allows you to
382	add, modify, delete, configure, and control classes, jobs, and
383	printers.</P>
384
385	<H2 CLASS="title">Software Using CUPS</H2>
386
387	<P>A lot has happened since CUPS 1.0 came out, and many software
388	packages are supporting CUPS. We have contributed code to the
389	SAMBA team to support CUPS, and parts of that are already
390	available in SAMBA 2.0.6 and 2.0.7. With any luck the final
391	pieces that provide a complete integration with SAMBA will be
392	available in the next release of SAMBA.</P>
393
394	<P>Two graphical interfaces have appeared on the scene that use
395	CUPS as well. The KUPS project provides a KDE-based interface
396	for CUPS and can be found at:</P>
397
398	<pre>
399	<A HREF="http://kups.sourceforge.net">http://kups.sourceforge.net</A>
400	</pre>
401
402	<P>The X Printing Panel (XPP) project provides a graphical
403	printing panel for CUPS and can be found at:</P>
404
405	<pre>
406	<A HREF="http://www.phy.uni-bayreuth.de/till/xpp">http://www.phy.uni-bayreuth.de/till/xpp/</A>
407	</pre>
408
409	<P>Numerous other filters, drivers, tutorials, etc. have been
410	made available on the CUPS Links web page, available at:</P>
411
412	<pre>
413	<A HREF="http://www.cups.org/links.php">http://www.cups.org/links.php</A>
414	</pre>
415
416	<P>Finally, our own ESP Print Pro software uses CUPS to provide
417	drivers for thousands of printers and can be found at:</P>
418
419	<pre>
420	<A HREF="http://www.easysw.com/printpro">http://www.easysw.com/printpro</A>
421	</pre>
422
423	<H2 CLASS="title">Operating Systems Using CUPS</H2>
424
425	<P>One of our goals has always been to get as many UNIX/Linux
426	distributions using CUPS as possible. Debian is currently
427	providing CUPS as part of its stable distribution, and many
428	other distributions are considering it in their next
429	releases.</P>
430
431	<H2 CLASS="title">Summary</H2>
432
433	<P>The Common UNIX Printing System provides a modern printing
434	interface for UNIX applications that is both flexible and
435	user-friendly. The software provides System V and Berkeley
436	compatible command-line interfaces to ensure compatibility with
437	existing applications. CUPS 1.2 adds many new features that make
438	it an even better choice for printing under UNIX.</P>
439
440	<H2 CLASS="title">Who to Contact</H2>
441
442	<P>For more information on CUPS please contact us at:
443
444	<pre>
445	Attn: CUPS Information
446	Easy Software Products
447	44141 Airport View Drive Suite 204
448	Hollywood, Maryland 20636-3142 USA
449
450	+1.301.373.9600
451
452	<A HREF="mailto:cups-info@cups.org">cups-info@cups.org</A>
453	</pre>
454
455	<H2 CLASS="title">References</H2>
456
457	<DL>
458
459	<DT>IEEE-1387.4</DT>
460
461	<DD>System Administration - Part 4: Printing Interfaces
462	(draft)</DD>
463
464	<DT><A HREF="http://www.pwg.org/ipp/index.html">IETF-IPP</A></DT>
465
466	<DD>Internet Printing Protocol/1.1</DD>
467
468	<DT><A HREF="http://www.astart.com/lprng.html">LPRng</A></DT>
469
470	<DD>An enhanced, extended, and portable implementation
471	of the Berkeley LPR print spooler functionality</DD>
472
473	<DT>Palladin</DT>
474
475	<DD>A printing system developed at the Massachussetts
476	Institute of Technology</DD>
477
478	<DT><A HREF="http://www-usa.iona.com//hyplan/jmason/plp.html">PLP</A></DT>
479
480	<DD>The Portable Line Printer spooler system</DD>
481
482	<DT><A HREF="http://www.ietf.org/rfc/rfc1179.txt">RFC1179</A></DT>
483
484	<DD>Line Printer Daemon Protocol</DD>
485
486	<DT><A HREF="http://www.ietf.org/rfc/rfc2046.txt">RFC2046</A></DT>
487
488	<DD>Multipurpose Internet Mail Extensions (MIME) Part
489	Two: Media Types</DD>
490
491	<DT><A HREF="http://www.ietf.org/rfc/rfc2616.txt">RFC2616</A></DT>
492
493	<DD>Hypertext Transfer Protocol -- HTTP/1.1</DD>
494
495	</DL>
496
497	<H2 CLASS="title">Trademarks</H2>
498
499	<P>The Common UNIX Printing System, CUPS, and the CUPS logo are
500	the trademark property of Easy Software Products. All other
501	trademarks are the property of their respective owners.</P>
502
503	</BODY>
504	</HTML>