Chapter 8. Hard Drives. Inside the Drive. Aluminum platters are coated with a magnetic medium. Platters spin at 3,500 to 10,000 rpm and read/write head “floats across platters.” Never open a hard drive: the littlest bit of dust could cause catastrophic damage. Data Encoding.
IBM thought that dealing with CHS was too hard for most users so they created 15 hard drive types for the 286 AT.