Managing dynamically loadable kernel modules

Managing dynamically loadable kernel modules

Dynamically loadable kernel modules (DLKMs) allow system resources to be conserved and allow you to make changes in the kernel configuration without the need to bring the system down and back up again. DLKMs are kernel modules that can be loaded and unloaded automatically while the system is running. This allows you to keep the kernel smaller because infrequently used drivers are unloaded when they are not needed.

Examples of DLKMs are device drivers, filesystems, and STREAMS modules. Previously, to install and use a new module, you had to do an idbuild, shut down your system, and then bring the system back up. Now, you can use a DLKM and avoid this work and the delay. Floppy disk drivers and mouse drivers are two examples of kernel modules that are typically configured as DLKMs.

Dynamically loadable kernel modules can be autoloaded or unloaded by the kernel, or demand-loaded or unloaded by you. Carefully consider the decision to demand-load or demand-unload DLKMs, especially if you are not an experienced system administrator. Disturbing the complex interrelationship of system files and parameters can, if not carefully handled, result in an unusable system from which recovery will not be simple or done quickly. In most cases, allowing the automatic process to prevail will provide the performance improvements you may be seeking.

Next topic: Static modules

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UnixWare 7 Release 7.1.4 - 22 April 2004