kconfig(5)							File Formats Manual							kconfig(5)

NAME

       kconfig - introduction to kernel configuration commands

DESCRIPTION

       HP-UX contains a set of commands used to view and modify the configuration of the HP-UX kernel.	The commands are:

	      Operations on complete kernel configurations

	      Operations on kernel modules

	      Operations on kernel tunable parameters ("tunables")

	      Retrieves pathnames of kernel files

	      Searches and displays the kernel configuration log file

	      Builds a kernel configuration from a system file

KERNEL CONFIGURATIONS

       The  set  of  data  that controls the behavior and content of the HP-UX kernel is called a kernel configuration.  System administrators may
       save any number of kernel configurations, and may load any one of them at any time.   A	kernel	configuration  consists  of  module  usage
       choices made using and tunable values chosen using

       By  default,  these commands affect the state of the currently running system.  When these commands are given a option, they instead affect
       the saved kernel configuration named config.

       The currently running kernel configuration can be saved using A saved configuration can be loaded using This causes the state of  the  run-
       ning system to be changed to match the saved configuration.  A saved configuration can be marked for use when the system is next booted, by
       using This makes no change to the state of the running system, but causes the specified saved configuration to be loaded when the system is
       rebooted.  (See below.)

       Saved  kernel configuration names must start with a letter; contain only letters, digits, and underscores (_); and be at most 32 characters
       in length.  The names are case-distinct.

   Backup Configuration
       The system maintains a saved configuration called which can be used to recover from configuration errors.  Depending on the selected backup
       behavior,  the  system  can automatically save the currently running configuration to immediately before making any requested change to the
       configuration.  The backup behavior is set using the option to the or commands.	The recognized backup behaviors are:

	    Always update the
		      configuration before making a change.

	    Update the
		      configuration before making the current change.  For subsequent changes, ask whether to update it.

	    Do not update the
		      configuration before making the current change.  For subsequent changes, ask whether to update it.

	    Never update
		      configuration before changes.

	    These behaviors can be abbreviated to one letter.  For compatibility with previous releases, is  accepted  as  an  alias  for  and	is
	    accepted as an alias for These aliases will be removed in a future release.

       After  each  boot,  the default backup behavior is to ask whether to update the configuration before each change.  Changes made noninterac-
       tively assume a "no" response.

   Dynamic and Static Changes
       By default, the kernel configuration tools will apply configuration changes to the currently running system, causing an immediate change in
       their  behavior.   System  administrators  can  override this default by specifying the option to changes made using the or commands.  This
       option causes the change(s) to be held until the system is rebooted.  HP recommends that this option be used only when the next	reboot	is
       expected  to  happen  soon.  If the reboot doesn't happen for months after the change, the change could come as an unwelcome surprise to an
       administrator who had forgotten the request.

       Some configuration changes cannot be applied without a reboot.  These changes will be held until the system is rebooted even if the  option
       is not specified.  In these cases, a warning message will be printed.

       If  multiple  configuration  changes are requested in a single invocation of one of the kernel configuration commands, and any one of those
       changes requires a reboot, all of the requested changes will be held until the system is rebooted.  In particular, if a saved  kernel  con-
       figuration  is  loaded using and that configuration cannot be used without a reboot, the state of the running system is not changed and the
       specified kernel configuration is marked to be used at next boot.

       If a change to a configuration is being held until next boot, and a subsequent change to the same configuration setting is made with  imme-
       diate effect, the immediate change will take precedence.  The first change will not take effect at next boot.  A warning will be printed in
       these situations.

       Changes that replace the entire currently running configuration, such as (import), (load), or (nextboot), cause any changes being held  for
       next boot to be discarded.

       Changes	that  are  made to the currently running system are retained when the system is rebooted.  They remain in effect until changed, or
       until a saved kernel configuration is loaded.

   Boot Behavior
       When the system is booted, the administrator may specify the name of a saved kernel configuration on the boot command  line  (see  hpux(1M)
       and hpux.efi(1M)).  If so, that kernel configuration will be loaded during boot.

       If  no  kernel  configuration is specified on the boot command line, the system will look for any kernel configuration that had been marked
       for use at next boot (via a or command).  If any such configuration is found, that configuration will be loaded during boot.

       If no kernel configuration is specified on the boot command line, and none is marked for use at next boot, the system will boot	using  the
       same configuration that was in use before the reboot.  If the configuration had any changes that were being held for reboot, either because
       they could not be applied without a reboot or because the option was used, those changes will be applied during the boot process.

       If the kernel configuration fails to boot properly, recovery can be attempted by booting the configuration and/or booting with  the  "fail-
       safe boot" flag on systems, on PA-RISC systems).  See hpux(1M) and hpux.efi(1M) for details.

SYSTEM FILES

       Users of past releases of HP-UX may be used to keeping kernel configuration choices in a text file called Such a file is known as a "system
       file".  A system file is automatically maintained for the currently running kernel configuration.  This file can be found at  System  files
       are  also  automatically maintained for each saved kernel configuration.  These files can be found at where config is the name of the saved
       configuration.  Any time a kernel configuration (saved or current) is changed using one of the kernel configuration  commands,  the  corre-
       sponding  system  file automatically gets rewritten to reflect the change.  System files can also be generated on demand for any configura-
       tion using The format of a system file is described in system(4).

       It is possible to make configuration changes by modifying a system file in a text editor and then running This command will read the system
       file  and  modify  the appropriate kernel configuration to match the contents of the system file.  can also read a system file and modify a
       kernel configuration.  It is retained for compatibility with previous releases of HP-UX.

       Note:   Some configuration changes can be made without using one of the kernel configuration commands (for example, by calling the or  sys-
	       tem  calls directly).  In these cases, the system files are not automatically updated.  Be sure to update them manually, or re-cre-
	       ate them using before using them.

       Note:   Avoid putting comments in a system file.  System files get re-created every time a kernel configuration change is  made,  and  com-
	       ments are not preserved in this process.

       System  files  can  be  useful for propagating kernel configurations to other systems.  To do so, use to export a configuration to a system
       file on a source machine.  Move the file to one or more target machines and use to import the system file into a configuration on the  tar-
       get.   The  target machines must have the same kernel filesets installed, or the import operation may fail.  The flag can be used to ensure
       that the target machine has exactly the same versions of kernel filesets installed.

       If there are changes to the currently running kernel configuration that are being held for reboot, those changes are reflected in the  sys-
       tem file

LOG FILE

       The  kernel  configuration  commands  maintain a log file that describes all kernel configuration changes.  This log file is located at The
       command can be used to search and view the log file, or to make entries that don't correspond to configuration changes.

       When making a configuration change using any of the commands, you can specify a comment option.	The commands will  include  the  specified
       comment in the log file entry describing the change.  Note that the comment usually must be quoted to avoid interpretation by the shell.

       Some configuration changes can be made without using the kernel configuration commands.	No log file entries are made for such changes.

       The  format  of	the  log  file may be changed without notice.  Programs must use the command to retrieve entries from the file rather than
       attempting to parse the file format.

DIAGNOSTICS

       All error, warning, and note messages printed by the kernel configuration commands are numbered.  For aesthetic reasons, the  message  num-
       bers are not usually displayed.	To enable display of the message numbers, set the environment variable to 1.

PARSING OUTPUT

       Most  of the kernel configuration commands produce tabular output describing the details of a configuration.  Such output may be attractive
       for humans, but can be difficult for scripts and applications to parse.	Also, the tabular output format can change at any time: for  exam-
       ple, between different types of systems or between releases of HP-UX.

       For  these  reasons,  each  of the kernel configuration commands that produce such output accept a option, which changes the output format.
       The format is designed to be easy to parse, and is guaranteed not to change.  HP will not support applications and scripts which parse  the
       output of the kernel configuration commands unless they use the option.

       The  option must be followed by a comma-separated list of field names.  Each kernel configuration command supports a different set of field
       names; refer to the man page for the command for a list.  The field names must appear in a single argument, so there should  be	no  spaces
       anywhere in the list.  For example,

       The  kernel  configuration  command will produce output that consists of a series of lines describing one object, a blank line, a series of
       lines describing the next object, a blank line, and so on until all objects are described.  Each line in the series  consists  of  a  field
       name,  a  single tab character (ASCII 9), and the value of that field for the object being described.  The lines occur in the same order as
       requested.  So the above command might produce this output:

       Some fields may occur multiple times within an object, or may not occur at all.	This will be noted in the description of the  field.   For
       example, the command

       might produce this output:

       This shows that has no dependencies, but is dependent on two other modules.

       New fields may be added at any time, but they will not be included in the output unless specified in a option.  Fields will not be removed.
       In rare cases, future developments may render a field meaningless.  In these cases, the field name will still be accepted  but  the  corre-
       sponding lines will be omitted from the output.

SEE ALSO

       hpux(1M), hpux.efi(1M), kclog(1M), kcmodule(1M), kconfig(1M), kcpath(1M), kctune(1M), mk_kernel(1M), modload(2), settune(2), system(4).

       available on

																	kconfig(5)