struct dirent {
     char dir_name[29];
     char dir_addr[3];
     };

struct fildes {
     char      fd_att;
     unsigned  fd_own;
     char      fd_date[5];
     char      fd_link;
     long      fd_fsize;
     char      fd_dcr[3];
     struct {
          char     addr[3];
          unsigned size;
          } fdseg[48];
     };

struct ddsect {
     char      dd_tot[3];
     char      dd_tsk;
     unsigned  dd_map;
     unsigned  dd_bit;
     char      dd_dir[3];
     unsigned  dd_own;
     char      dd_att;
     unsigned  dd_dsk;
     char      dd_fmt;
     unsigned  dd_spt;
     unsigned  dd_res;
     char      dd_bt[3];
     unsigned  dd_bsz;
     char      dd_date[5];
     char      dd_na