The kernel also handles the much-needed task of abstracting all forms of file IO. Imagine what would happen if every program had to interface with your specific disk hardware directly -- if you changed disk controllers, all your programs would stop working! Fortunately, the Linux kernel follows the UNIX model of providing a simple data storage and access abstraction that all programs can use. That way, your favorite database doesn't need to be concerned whether it is storing data on an IDE disk, on a SCSI RAID array, or on a network-mounted file system.