The floppy drive controller "manages" or operates the floppy drive. When the CPU needs to do a read/write operation, it talks to the floppy drive controller instead of the floppy drive itself. This saves the CPU time, and allows the floppy drive controller to worry about telling the floppy drive what to do.

The floppy drive controller can be on an expansion card that takes up an expansion slot, or built right into the motherboard. This type of motherboard is called an integrated motherboard.