XSTART(1)

NAME
Xstart - start a suitable X server

SYNOPSIS
Xstart [server arguments]

DESCRIPTION
Xstart simply starts an X server with appropriate arguments for running under xdm(1). It may be used directly in the same was as Xarm(1) and with the same arguments, or it may be used indirectly as a result of typing x at the login prompt. In either case the file /etc/xdm/Xconfig is read to find arguments to supply to the X server. The server is started with the -query, -once, and -authKeyFile arguments to cause it to contact xdm. These arguments are followed by any arguments specified in the /etc/xdm/Xconfig file and then any given on the command line.

Xdm will prompt for a login name and user name and then start a normal X session. At the end of the session the server will shut down and control will be returned to the terminal from which Xstart was started.

FILE FORMAT

The /etc/xdm/Xconfig file consists of any number of lines of keywords and values. Each line should start with a keyword which may then be followed by a series of values. Non-numeric values may be quoted (single or double quote characters) and may contain the quote characters if they are preceded by a \ character. Characters may also be specified as octal values using the normal \nnn format, where each n is an octal digit.

Any line which starts with a # character is skipped. The supported keywords are as follows:-

AUTHOR
    Followed by the name of the author of the file. This argument is effectively ignored. It is provided to allow the xadmin(1) program to detect a machine generated file (in which case the author will be /etc/rc.X).

VDU-TYPE
    Followed by a single numeric argument specifies a default for the monitor type. Normally Xstart obtains the monitor type from the operating system. If this cannot be done the first VDU-TYPE value in the file will be used. This keyword must precede all argument specifications.

XSERVER
    The single argument is the name of the X server to execute. This defaults to /usr/bin/X11/Xarm.

MULTIPLE-SESSION
    This keyword takes no arguments. It causes the server to be run without the -once flag so that it will not exit at the end of the first session.

XDM-HOST
    The single argument specifies the name of the host for Xarm to contact (the argument to the server -query flag). This defaults to loopback (the machine on which Xstart is run).

AUTHENTICATION
    The single argument is the name of the authentication file. This defaults to /etc/xdm/Xkeys. To make authentication useful this file should be readable only by the super-user.

NOAUTHENTICATION
    This keyword switches off authentication.

NODEFAULTS
    This keyword prevents any of the following vdu type specific arguments being added to the server command line.

The remaining keywords allow additional arguments to be specified for the server. These are typically used to control the number of screens which the server supports and the screen modes used. The Xstart program does not check these arguments.

ARGUMENTS
    The arguments are added to the server command line. The keyword may be given multiple times. The arguments consist of everything following the keyword to the end of the line.

LOWRES-ARGUMENTS
    The arguments are added if the vdu type is 0 (corresponding to a low resolution monitor).

MULTISCAN-ARGUMENTS
    The arguments are added if the vdu type is 1 (corresponding to a multi-scan monitor).

HIGHRES-ARGUMENTS
    The arguments are added if the vdu type is 2 (corresponding to a high reolution black and white monitor).

VGA-ARGUMENTS
    The arguments are added if the vdu type is 3 (corresponding to a VGA monitor).

SUPERVGA-ARGUMENTS
    The arguments are added if the vdu type is 4 (corresponding to a Super VGA monitor).

NOTES

The Xstart program is designed to be used as a login shell in the /etc/passwd file. When used as such it starts an X server according to the configuration information in /etc/xdm/Xconfig. If that file does not exist (or is not readable) an X server will not be started - effectively use of X can be disabled by removing /etc/xdm/Xconfig. When the X server is started in this way error messages from the server will appear on the login terminal. If these appear while the X server is actually on display the border of the screen will flash until the terminal is selected (using the Break key).

In normal use the /etc/xdm/Xconfig file is machine regenerated during startup under the control of the /etc/rc.X script. Editing the file will thus only have a temporary effect on the server configuration. The /etc/rc.X script copies the contents of one of the files /etc/xdm/Xconfig.<size>Mbytes where <size> is replace by the amount of physical memory on the machine (4, 8, 12 or 16 Mbytes). This allows the X server to be appropriately configured for machines with less memory. Editing any of these files will make a permanent change in the configuration for the relevant memory size.

Removing /etc/xdm/Xconfig will prevent /etc/rc.X from recreating it (assuming /etc/rc.X has not been changed) and will thus prevent the X login.

The different files and the support within the files for differing vdu types allow the default system to deal with any of the supported memory and screen configurations. If (as is normally the case) a machine is to be permanently configured with a fixed amount of memory and a fixed screen type the /etc/xdm/Xconfig file itself can be edited to reflect the configuration; if the AUTHOR field in the file is changed or removed /etc/rc.X will not modify the file.

SEE ALSO
xadmin(1), xdm(1), Xarm(1), Xserver(1)

COPYRIGHT
Copyright (c) 1990, Acorn Computers Ltd.

AUTHOR
John Bowler, Acorn Computers Ltd.