Generally, slab, face, and side milling are performed on a horizontal milling machine.� End milling, also called vertical milling, is generally performed on a vertical milling machine.
	Slab and side milling are fairly similar, with the main difference being the length of the cutter-- slab generally designed to cut all of the workpiece while side just a small section of it-- and the fact that side cutters will often have contours machined into them.