DEVICE DRIVERS IN LINUX
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* Linux device driver kernel files are in /dev
* Drivers are either compiled into the kernel, or loaded as kernel modules
* Linux device driver kernel modules can be configured, loaded, unloaded 
  without rebooting the system
* Not all device drivers are kernel devices, such as video drivers for xwindows
* The programs insmod, rmmod, ksyms, lsmod, genksyms, modprobe, and depmod are
  part of "module utilities" and when installed, the commands are in /sbin

Loading a Device Driver Kernel Module:
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Use modprobe to load a kernel module into the running kernel.  You can specify 
parameters with modprobe too.

  modeprobe <module name>

Other commands, such as to show the loaded modules or inserting a module into
the running kernel

  lsmod
  insmod

Modules usually have an extension of ".o"  

Modules can be loaded when the system boots.  They are specified in the text 
configuration file:  /etc/modules  It contains a list of modules to be loaded.
Options for the modules are in the file:  /etc/conf.modules
Rather than directly editing the conf.modules with vi, use the script provided
for that purpose

  update-modules

Unloading a Device Driver Kernel Module:
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If the module is not used by the system, it may be unloaded by either of the
following methods:

  modprobe -r <module_name>
  rmmod <module_name>

Module related command reference:
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  lsmod - list loaded modules
  insmod - install loadable kernel module
  modprobe - high level handling of loadable modules
  depmod - handle dependency descriptions for loadable kernel modules
  rmmod - unload loadable modules
  ksyms - display exported kernel symbols