Hard disk drive platter

A hard disk drive platter or hard disk is the circular magnetic disk on which digital data is stored in a hard disk drive. The rigid nature of the platters is what gives them their name (as opposed to the flexible materials which are used to make floppy disks). Hard drives typically have several platters which are mounted on the same spindle. A platter can store information on both sides, typically requiring two recording heads per platter, one per surface. A hard drive's platter/s are some of the smoothest surfaces known currently manufactured, platters are manufactured, polished, and burnished in ultra-clean environments- often 100 times cleaner than a hospital operating room to ensure no imperfections. This allows heads to fly at extremely low distances at a few nanometres enabling higher density than in the past.