Installation guide

Conﬁguring the Kernel

The Tru64 UNIX kernel is a memory-resident executable image that

handles all the system services −− hardware interrupts, memory

management, interprocess communication, process scheduling −− and

makes all other work on the operating system possible. In addition to the

code that supports these core services, the kernel contains a number of

subsystems.

A subsystem is a kernel module that extends the kernel beyond the core

kernel services. File systems, network protocol families, and physical and

psuedodevice drivers are all examples of supported subsystems. Some

subsystems are required in the kernel, while others are optional. You

conﬁgure your kernel by adding and removing these optional subsystems.

You also conﬁgure your kernel by tuning certain values stored in it. For

example, the kernel contains values that can be adjusted to help make disk

access faster. Modifying those values to optimize disk access can improve

your system’s performance.

The system provides two methods of conﬁguring your kernel: the dynamic

method and the static method. Dynamic system conﬁguration entails using

commands to conﬁgure the kernel. Static system conﬁguration entails

modifying system ﬁles and rebuilding the kernel. Modifying system ﬁles

and rebuilding the kernel can be a difﬁcult process, so use dynamic kernel

conﬁguration whenever possible.

This chapter helps you understand kernel conﬁguration by explaining the

following:

• How the kernel is conﬁgured at installation time

• How to determine whether you need to conﬁgure your kernel and which

conﬁguration method to use, static or dynamic

• How to conﬁgure your system dynamically, using commands

• How to conﬁgure your system statically, by modifying system ﬁles and

rebuilding the kernel

Conﬁguring the Kernel 5–1