HP-UX System Administrator's Guide: Configuration Management

TIP: To see if a module is required, look to see whether unused appears on the
Capable line. If it does, the module is not required.
Modules often have dependencies between them. For example, device drivers typically
cannot be configured into the kernel unless the driver support modules are also
configured. Dependencies like this are shown on the Depends On lines in the output.
A module can be dependent on a particular other module, specified by name and
version. A module can also be dependent on an interface that must be supplied by
some other module, without saying specifically which modules supply that interface.
Modules that supply such interfaces have an Exports line in the output, listing the
interfaces they export.
Changing Module States
To change the state of a module, put module state assignments on the kcmodule
command line. (Also see “Managing Configurations with System Files” (page 192).) For
example, to load the CD File System module, named cdfs:
# kcmodule cdfs=loaded
In fact, loaded is the developer-chosen best state for cdfs, so this is the same as:
# kcmodule cdfs=best
To unload it:
# kcmodule cdfs=unused
See the kcmodule(1M) manpage for details.
When you change a module state using a command as in the above examples, the
change will be made immediately to the currently running system, if possible. Sometimes
it’s not possible to make the change immediately; for example, there might be a CD
file system mounted, in which case cdfs can’t be unloaded. In those cases, kcmodule
will hold the change and apply it at next boot. A change that moves a module into or
out of static state can never be applied immediately, and will always be held for
next boot. If any change on the kcmodule command line has to be held for next boot,
they all will be.
CAUTION: Unloading an I/O interface device driver assigned to a critical resource,
such as a boot disk driver, is not immediate but is held for next boot. Removing a boot
disk driver will result in an unbootable system. You can run kcmodule -D to see what
modules will be removed at next boot. Run kconfig -H to discard all changes pending
for the next boot.
When modules are moved into or out of static state, the kcmodule command will
run for quite a while. This is because such changes require that the kernel executable
be relinked. If you have multiple such changes to make, it is best that you list them all
164 Configuring the Kernel