This structure is used (at the end of an IoctlDeviceParmsRec in the
 following IOCTL fns:

    440dH 40H (set device parameters)
    440dH 60H (query device parameter)
    DvRq 13H  (generic IOCTL for block devices)

  Offset Size Contents
  ▀▀▀▀▀▀ ▀▀▀▀ ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
    +0     2  rSectCnt     sectors per track
    +2    n*4 arLayout     variable-length array of 2-word sector
                           Each element is: WORD: sector number
                                            WORD: sector size
          2+(n*4)          size of a TrackLayoutRec structure

   Notes: This structure is needed to create "sector interleave" in which
          the sectors are not numbered sequentially on the physical medium.
          The idea is to let the disk spin for a partial rotation while the
          hardware is processing the data, with the ultimate goal being to
          access an entire track without wasting time waiting for the data
          to come under the head.

          Example layout:

             DW  9      ; nine sectors per track
             DW  1,512  ; first sector is #1 (size is 512 bytes)
             DW  5,512  ; next sector is #5
             DW  2,512  ; next sector
             DW  6,512  ; next sector
             DW  3,512  ; next sector
             DW  7,512  ; next sector
             DW  4,512  ; next sector
             DW  8,512  ; next sector
             DW  9,512  ; next sector

          DOS device drivers do not keep a track layout table for each
          logical device.  A generic IOCTL Set Parameters (440dH 40H) call
          must be made when the attributes of the media change.

See Also: fn 440dH (Generic IOCTL for block devices)
          INT 13H 05H (format track)
          Device Drivers
          DOS Functions