NAME

X - X Window System server

SYNOPSIS

X [:displaynumber] [-option ...] [ttyname]

DESCRIPTION

X is the generic name for the X Window System server and is started from the xinit(1) program. The displaynumber argument is used by clients in their DISPLAY environment variables to indicate which server to contact (large machines may have several displays attached). This number is usually in the range of 0-6 and is also used in determining the names of various startup files.

The executable that is invoked when X is run is actually one of a collection of programs that depend on the hardware that is installed on the machine.

STARTING THE SERVER

Installations that run more than one window system will still need to use the xinit utility. However, xinit is to be considered a tool for building startup scripts and is not intended for use by end users. Site adminstrators are strongly urged to build nicer interfaces for novice users.

When the sample server starts up, it takes over the display. If you are running on a workstation whose console is the display, you cannot log into the console while the server is running.

OPTIONS

The following options can be given on the command line to any X server. Any items marked with <no action> are not supported by the AT&T X server.

-a number

sets pointer acceleration (i.e. the ratio of how much is reported to how much the user actually moved the pointer). <no action>

-bs     disables backing store support on all screens.

-c      turns off key-click. <no action>

c volume

sets key-click volume (allowable range: 0-8). <no action>

-f volume

sets feep (bell) volume (allowable range: 0-7).

-logo turns on the X Window System logo display in the screen-saver.

nologo turns off the X Window System logo display in the screen-saver.

-p minutes

sets screen-saver pattern cycle time in minutes.

-r      turns off auto-repeat. <no action>

r       turns on auto-repeat.

-s minutes

sets screen-saver timeout time in minutes.

-su     disables save under support on all screens.

-t numbers

sets pointer acceleration threshold in pixels (i.e. after how many pixels pointer acceleration should take effect). <no action>

-to seconds

sets default connection timeout in seconds.

v       sets video blanking on for screen-saver preference.

-v      sets screen-saver preference without video blanking.

-co filename

        sets name of RGB color database

-help   prints a usage message

-fp fontPath

        sets the search path for fonts

-fc cursorFont

        sets default cursor font

-fn font

        sets the default font

-wm     forces the default backing-store of all  windows  to
        be   WhenMapped;   a  cheap  trick  way  of  getting
        backing-store to apply to all windows.

Many servers also have device-specific command line options. See the manual pages for the individual servers for more details.

SECURITY

The sample server uses an access control list for deciding whether or not to accept connections from clients on a particular machine. This list initially consists of the host on which the server is running as well as any machines listed in the file /etc/Xn.hosts, where n is the display number of the server.

Users can add or remove hosts from this list and enable or disable access control using the xhost command from the same machine as the server.

Unlike some window systems, X does not have any notion of window operation permissions or place any restrictions on what a client can do; if a program can connect to a display, it has full run of the screen. The core protocol does have support for providing authentication information when establishing connections, but is not used in the sample implementation. Sites that have authentication and authorization systems (such as Kerberos) might wish to make use of the hooks in the libraries and the server to provide additional security.

Fonts are usually stored as individual files in directories. The list of directories in which the server looks when trying to open a font is controlled by the font path. Although most sites will choose to have the server start up with the appropriate font path (using the -fp option mentioned above), it can be overridden using the xset program.

The default font path for the sample server contains three directories:

/usr/lib/X11/fonts/misc

This directory contains several miscellaneous fonts that are useful on all systems. It contains a very small family of fixed-width fonts (6x10, 6x12, 6x13, 8x13, 8x13bold, and 9x15) and the cursor font. It also has font name aliases for the commonly used fonts fixed and variable.

/usr/lib/X11/fonts/75dpi

This directory contains fonts contributed by Adobe Systems, Inc. and Digital Equipment Corporation and by Bitstream, Inc. for 75 dots per inch displays. An integrated selection of sizes, styles, and weights are provided for each family.

/usr/lib/X11/fonts/100dpi

This directory contains versions of some of the fonts in the 75dpi directory for 100 dots per inch displays.

An additional directory, /usr/lib/X11/fonts/Xol, contains the OPEN LOOK fonts. This directory is not part of the server's default font path, but can be set using the XWINFONTPATH environment variable. The XWINFONTPATH is an environment variable that should be set to the full pathname of the directories that should be part of the server's default font path. This variable should be exported. For example, to include the OPEN LOOK fonts in the server's default font path put the following commands in a startup file:

XWINFONTPATH=/usr/lib/X11/fonts/Xol,/usr/lib/X11/fonts/misc/,/usr
      /lib/X11/fonts/ 75dpi/,/usr/lib/X11/fonts/100dpi
export XWINFONTPATH

Both the default font path and the XWINFONTPATH environment variable can be overriden by using a command line argument when starting the server.

Font databases are created by running the mkfontdir program in the directory containing the compiled versions of the fonts (the .snf files). Whenever fonts are added to a directory, mkfontdir should be rerun so that the server can find the new fonts. If mkfontdir is not run, the server will not be able to find any fonts in the directory.

DIAGNOSTICS

Too numerous to list them all. If run from init(8), errors are logged in the file /usr/adm/X*msgs,

FILES

/etc/X*.hosts                 Initial access control list

/usr/lib/X11/fonts/misc/,/usr/lib/X11/fonts/75dpi/,/usr/lib/X11/fonts/100dpi
                              Font directories

/usr/lib/X11/rgb.<display_type>.txt

                              Color database

/usr/adm/X*msgs               Error log file

SEE ALSO

X(1),  mkfontdir(1), xinit(1), xterm(1), olwm(1),  xhost(1),
xset(1),  xsetroot(1),  X Window System Protocol, Definition
of the Porting Layer for the X v11 Sample Server, Strategies
for  Porting  the  X  v11 Sample Server, Godzilla's Guide to
Porting the X V11 Sample Server

BUGS

The option syntax is inconsistent with itself and xset(1).

The acceleration option should take a numerator and a denominator like the protocol.

The color database is missing a large number of colors. However, there doesn't seem to be a better one available that can generate RGB values tailorable to particular displays.

CAVEAT

The X server must be killed with -2 an NOT -9; this allows the server environment to reset itself to its previous state. The X server resets itself to default settings when no clients are active.

COPYRIGHT

Copyright 1984, 1985, 1986, 1987, 1988, Massachusetts Insti-
tute of Technology.