3 Kernel

The kernel of any operating system is the most basic core of the operating system. The kernel is usually responsible to allocate resources such as memory (RAM), processor time, abstract files, the starting and stopping of running programs and I/O (input/output) resources.

A kernel typically has very little, if any, knowledge of the actual hardware devices in a system. It does need to understand enough about basic devices. Basic devices recognized by a kernel include the following:

• Processor
• Memory (RAM)
• Basic IDE, SCSI or SATA controller
• Basic display card (text mode, or basic VGA mode)

For all other hardware devices that are not critical to the start up of the operating system, a kernel depends on ``kernel modules''. The interface between a kernel and kernel modules is flexible. This permits the update and addition of modules without having to change the kernel.