sector interleave
interleave
interleaving
sector interleaving
sector map

   (Or sector map) The mapping from logical to physical sector
   numbers on a magnetic disk designed to optimise sequential
   reads and writes.  Data is usually transferred to and from the
   disk in blocks or sectors where one sector lies within a
   continuous range of rotational angle of the disk.  If logical
   sectors are assigned sequentially to physical sectors
   (0,1,2,...) then by the time one sector has been read and
   processed (e.g. writen to main memory) the start of the next
   logical sector will have passed the read/write head and will
   not be accessible until the disk's rotation brings it back
   under the head.

   Staggering the physical sectors (e.g. 0,3,6,1,4,7,2,5,8) aims
   to allow just enough time deal with one sector before the next
   is accessible.  This obviously depends on the relative speed
   of the rotation of the disk, sector size, sectors per track
   and the speed of transfer of sectors to main memory.