HDD Structure

• A disk is made of one or more platers.
• Each plater is split into tracks.
• Each track is split into sectors (of a fixed size)
  • thus outer tracks contain more sectors.
• Each plater may be two-sided, and has a read/write head.
• All read/write heads are handled by a single arm, and thus all move together.
• All tracks that can be accessed at once on all platers (i.e. that sit at the same distance from the outer edge) are collectively called a Cylinder.

Originally written by guy keren