The Linux Kernel: Drivers
Drivers are small programs that enable the kernel to communicate and handle hardware or protocols (rules and standards). Without a driver, the kernel does not know how to communicate with the hardware or handle protocols (the kernel actually hands the commands to the BIOS and the BIOS passes them on the the hardware). The Linux Kernel source code contains many drivers (in the form of source code) in the drivers folder. Each folder within the drivers folder will be explained. When configuring and compiling the kernel, it helps to understand the drivers. Otherwise, a user may add drivers to the kernel that they do not need or leave out important drivers. The driver source code usually includes a commented line that states the purpose of the driver. For example, the source code for the tc driver has a single commented line that says the driver is for TURBOchannel buses. Because of the documentation, users should be able to look at the first few commented lines of future drivers to learn their purpose.
There are different terms that should be understood so that the information below is understandable. An I/O device is an Input/Output device.