HP-UX Reference (11i v2 03/08) - 5 Miscellaneous Topics, 7 Device (Special) Files, 9 General Information, Index (vol 9)

k
kconfig(5) 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:
kconfig Operations on complete kernel configurations
kcmodule Operations on kernel modules
kctune Operations on kernel tunable parameters ("tunables")
kcpath Retrieves pathnames of kernel files
kclog Searches and displays the kernel configuration log file
mk_kernel 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
kcmodule(1M) and tunable values chosen using kctune(1M).
By default, these commands affect the state of the currently running system. When these commands are
given a
-c config option, they instead affect the saved kernel configuration named config.
The currently running kernel configuration can be saved using
kconfig -s. A saved configuration can
be loaded using kconfig -l. This causes the state of the running 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 kconfig -n. 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 Boot Behavior , 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
backup, which can be used to recover from
configuration errors. The system automatically saves the currently running configuration to
backup
immediately before making any requested change to the configuration. This behavior can be disabled
using the -K option on the command line when a change is requested.
The first update of the
backup configuration after the system boots is treated specially, since it will
overwrite the backup of the configuration that was running before the reboot. Any time the
backup
configuration dates to before the time the system booted, the command making the configuration change
will ask for confirmation before replacing it. (If the command is running non-interactively, the answer is
assumed to be "no".) This behavior can be overridden by specifying the -B (update the backup) or -K
(don’t update the backup) flags on the command line for the change.
Dynamic and Static Changes
By default, the kernel configuration tools will apply configuration changes to the currently running sys-
tem, causing an immediate change in their behavior. System administrators can override this default by
specifying the
-h option to any of the 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 sys-
tem is rebooted even if the
-h 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 configuration is loaded using
kconfig -l, 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 immediate effect, the immediate change will take precedence. The first
Section 5−−130 Hewlett-Packard Company − 1 − HP-UX 11i Version 2: August 2003