What if Windows had every driver available already installed and you just had to turn on the drivers you needed? That is essentially what kernel modules do for Linux. Kernel modules, also known as a loadable kernel module (.ko files), are essential to keeping the kernel functioning with all of your hardware without consuming all of your available memory.
A module typically adds functionality to the base kernel for things like devices, file systems, and system calls. LKMs have the file extension .ko and are typically stored in the /lib/modules directory. Because of their modular nature you can easily customize your kernel by setting modules to load, or not load, during startup with the menuconfig command or by editing your /boot/config file, or you can load and unload modules on the fly with the modprobe command.
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| KO file is a Linux 2.6 Kernel Object. A loadable kernel module (LKM) is an object file that contains code to extend the running kernel, or so-called base kernel, of an operating system. |
A module typically adds functionality to the base kernel for things like devices, file systems, and system calls. LKMs have the file extension .ko and are typically stored in the /lib/modules directory. Because of their modular nature you can easily customize your kernel by setting modules to load, or not load, during startup with the menuconfig command or by editing your /boot/config file, or you can load and unload modules on the fly with the modprobe command.
Third party and closed source modules are available in some distributions, like Ubuntu, and may not be installed by default because the source code for the modules is not available. The developer of the software (i.e. nVidia, ATI, among others) do not provide the source code but rather they build their own modules and compile the needed .ko files for distribution.
KO modules may be loaded by using the insmod Linux program. Installed kernel modules can be listed using the lsmod program, or they may be browsed in the /proc/modules directory.As of Linux kernel version 2.6, KO files are used in place of .O files and contain additional information that the kernel uses to load modules. The Linux programmodpost can be used to convert O files into KO files.
A kernel is completely essential to any computer running properly. The Linux kernel is different than OS X and Windows because it includes drivers at the kernel level and makes many things more complex and time consuming.
