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OpenSolaris 2009.06 - man page for system (opensolaris section 4)

system(4)				   File Formats 				system(4)

NAME
       system - system configuration information file

DESCRIPTION
       The  system file is used for customizing the operation of the operating system kernel. The
       recommended procedure is to preserve the original system file before modifying it.

       The system file contains commands which are read by the kernel during  initialization  and
       used  to  customize  the operation of your system. These commands are useful for modifying
       the system's treatment of its loadable kernel modules.

       The syntax of the system file consists of a list of keyword/value pairs which  are  recog-
       nized  by the system as valid commands. Comment lines must begin with an asterisk (*) or a
       hash mark (#) and end with a newline character. All commands are  case-insensitive  except
       where noted.

       Commands  that  modify  the  system's  operation  with  respect to loadable kernel modules
       require you to specify the module type by listing the module's  namespace.  The	following
       namespaces are currently supported on all platforms:

       drv	 Modules in this namespace are device drivers.

       exec	 Modules  in this namespace are execution format modules. The following exec mod-
		 ules are currently provided:

		 Only on SPARC system:
					       aoutexec

		 Only on x86 system:
					       coffexec

		 On SPARC and IA systems:
					       elfexec
					       intpexec
					       javaexec

       fs	 These modules are filesystems.

       sched	 These modules implement a process scheduling algorithm.

       strmod	 These modules are STREAMS modules.

       sys	 These modules implement loadable system-call modules.

       misc	 These modules do not fit into any of the above  categories,  so  are  considered
		 "miscellaneous" modules.

       SPARC only:

       dacf    These modules provide rules and actions for device auto-configuration.

       tod     These modules provide support for the time of day hardware.

       cpu     These modules provide CPU-specific kernel routines.

       A description of each of the supported commands follows:

       exclude: <namespace>/<modulename>

	   Do  not  allow  the	listed	loadable kernel module to be loaded. exclude commands are
	   cumulative; the list of modules to exclude is created by combining every exclude entry
	   in the system file.

       include: <namespace>/<modulename>

	   Include  the  listed  loadable  kernel  module. This is the system's default, so using
	   include does not modify the system's operation. include commands are cumulative.

       forceload: <namespace>/<modulename>

	   Force this kernel module to be loaded during kernel initialization. The default action
	   is  to  automatically  load	the  kernel  module when its services are first accessed.
	   forceload commands are cumulative.

       rootdev: <device name>

	   Set the root device to the listed value instead of using the default  root  device  as
	   supplied by the boot program.

       rootfs: <root filesystem type>

	   Set the root filesystem type to the listed value.

       moddir: <first module path>[[{:, }<second ...>]...]

	   Set	the search path for loadable kernel modules. This command operates very much like
	   the PATH shell variable. Multiple directories to search can be listed together, delim-
	   ited either by blank spaces or colons.

       set [<module>:]<symbol> {=, |, &} [~][-]<value>

	   Set	an integer or character pointer in the kernel or in the selected kernel module to
	   a new value. This command is used to change kernel and module parameters and thus mod-
	   ify	the  operation	of your system. Assignment operations are not cumulative, whereas
	   bitwise AND and OR operations are cumulative.

	   Operations that are supported for modifying integer variables are: simple  assignment,
	   inclusive bitwise OR, bitwise AND, one's complement, and negation. Variables in a spe-
	   cific loadable module can be targeted for modification by specifying the variable name
	   prefixed  with  the kernel module name and a colon (:) separator. Values can be speci-
	   fied as hexadecimal(0x10), Octal(046), or Decimal(5).

	   The only operation supported for modifying character pointers  is  simple  assignment.
	   Static  string data such as character arrays cannot be modified using the set command.
	   Use care and ensure that the variable  you  are  modifying  is  in  fact  a	character
	   pointer.  The  set  command	is  very powerful, and will likely cause problems if used
	   carelessly. The following escape sequences are supported within the quoted string:

	     \n   (newline)
	     \t   (tab)
	     \b   (backspace)

EXAMPLES
       Example 1 A sample system file.

       The following is a sample system file.

	 * Force the ELF exec kernel module to be loaded during kernel
	 * initialization. Execution type modules are in the exec namespace.
	 forceload: exec/elfexec
	 * Change the root device to /sbus@1,f8000000/esp@0,800000/sd@3,0:a.
	 * You can derive root device names from /devices.
	 * Root device names must be the fully expanded Open Boot Prom
	 * device name. This command is platform and configuration specific.
	 * This example uses the first partition (a) of the SCSI disk at
	 * SCSI target 3 on the esp host adapter in slot 0 (on board)
	 * of the SBus of the machine.
	 * Adapter unit-address 3,0 at sbus unit-address 0,800000.
	 rootdev: /sbus@1,f8000000/esp@0,800000/sd@3,0:a
	 * Set the filesystem type of the root to ufs. Note that
	 * the equal sign can be used instead of the colon.
	 rootfs:ufs
	 * Set the search path for kernel modules to look first in
	 * /usr/phil/mod_test for modules, then in /kernel/modules (the
	 * default) if not found. Useful for testing new modules.
	 * Note that you can delimit your module pathnames using
	 * colons instead of spaces: moddir:/newmodules:/kernel/modules
	 moddir:/usr/phil/mod_test /kernel/modules.
	 * Set the configuration option {_POSIX_CHOWN_RESTRICTED} :
	 * This configuration option is enabled by default.
	 set rstchown = 1
	 * Disable the configuration option {_POSIX_CHOWN_RESTRICTED} :
	 set rstchown = 0
	 * Turn on debugging messages in the modules mydriver. This is useful
	 * during driver development.
	 set mydriver:debug = 1
	 * Bitwise AND the kernel variable "moddebug" with the
	 * one's complement of the hex value 0x880, and set
	 * "moddebug" to this new value.
	 set moddebug & ~0x880
	 * Demonstrate the cumulative effect of the SET
	 * bitwise AND/OR operations by further modifying "moddebug"
	 * by ORing it with 0x40.
	 set moddebug | 0x40

SEE ALSO
       boot(1M), init(1M), kernel(1M)

WARNINGS
       Use care when modifying the system file; it modifies the operation of the kernel.  If  you
       preserved  the  original  system  file,	you can boot using boot -a, which will ask you to
       specify the path to the saved file. This should allow the system to boot correctly. If you
       cannot  locate  a  system  file that will work, you may specify /dev/null. This acts as an
       empty system file, and the system will attempt to boot using its default settings.

NOTES
       The /etc/system file is read only once, at boot time.

SunOS 5.11				    3 Nov 2004					system(4)


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