CCC   Track-to-Sector Mapping data structure:

      Integer*4 max_trk_sec
      Integer*4 sec_maxlen
      Parameter (max_trk_sec = 30)
      Parameter (sec_maxlen  = 28000)

      STRUCTURE /sec_trk_map/
         Integer*4 sec_id         !  unique sector ID number
         Integer*4 n_trk_sec      !  Number of tracks assigned to sector
         Integer*4 flag           !  normally=0, if = 1 then more than
CCC                               !  max_trk_sec tracks could have been 
CCC                               !  assigned to this sector, however the
CCC                               !  maximum number that can be assigned is
CCC                               !  max_trk_sec.
         Integer*4 track_id(max_trk_sec)
CCC                               !  Foreign keys to tracks in /track/ that
CCC                               !  are assigned to this sector.
      END STRUCTURE