floating head

from The Free On-line Dictionary of Computing (8 July 2008)

hard disk
floating head

   <storage> (In contrast to {floppy disk}) A {magnetic disk}
   data storage device where the disks are rigid and fixed to a
   central axle.  They are usually packaged with associated
   read/write heads and electronics.  Most hard disks are
   permanently connected to the drive (fixed disks) though there
   are also {removable hard disks}.

   See {magnetic disk}.

   (2007-06-14)