Reconfiguring the Kernel in HP-UX Release 11i Version 1.5

Reconfiguring the kernel in HP-UX Release 11i Version 1.5
Reconfiguring the Kernel
Chapter 14
Reconfiguring the Kernel
For most systems, the default kernel configuration included with HP-UX will be sufficient for
your needs. However, in each of the following instances you need to reconfigure the kernel:
• Adding or removing device drivers
The most common reason for adding or removing kernel modules is to add or remove
device drivers. See Configuring HP-UX for Peripherals for full instructions on adding
peripherals.
You may also want to remove a driver from your kernel if your system is not using any
peripherals of that type. This is not required, but can be desirable if a smaller, more
efficient kernel is needed.
To add or remove traditional drivers which are statically linked to the kernel, a whole
kernel configuration and system reboot are required. See “Steps to Reconfigure the Kernel”
on page 6, and “Steps to Perform Whole Kernel Configuration Using HP-UX Commands”
on page 7 for details.
However, before you remove the driver, ensure that other drivers are not dependent on it
by checking the files in the directory /usr/conf/master.d/ for a table of driver
dependencies in the section DRIVER_DEPENDENCY. The file core-hpux will have the most
definitions, but other files in the directory can contain definitions as well.
If the device driver that controls the peripheral is a dynamically loadable module (a
DLKM), you may be able to add or remove the drivers from the running kernel without
needing to reboot. See the white paper Managing and Developing Dynamically Loadable
Kernel Modules for instructions on adding or removing DLKM modules.
• Modifying system parameters
You may need to change one or more tunable system parameters. For example, to
accommodate a specialized application or an exceptionally large number of users.
Historically, all tunables have been static, but as of HP-UX Release 11i, a tunable may be
either static, dynamic, or automatic.
❏ A static tunable is one whose value cannot be changed without rebooting the system.
Usually a kernel rebuild is also required.
❏ A dynamic tunable is one whose value can be changed without a reboot.
NOTE Although dynamic tunables are enabled on HP-UX Release 11i, they are not