Header Area

               |-------------------|-------------------|
     H.MPOF    |  Map Area Offset  | Ident Area Offset |   H.IDOF
               |-------------------|-------------------|
               |              File Number              |   H.FNUM
               |---------------------------------------|
               |         File Sequence Number          |   H.FSEQ
               |---------------------------------------|
               |         File Structure Level          |   H.FLEV
               |---------------------------------------|   H.FOWN
     H.PROJ    |            File Owner UIC             |   H.PROG
               |---------------------------------------|
               |            File Protection            |   H.FPRO
               |-------------------|-------------------|   H.FCHA
     H.SCHA    |   System Char.    |    User Char.     |   H.UCHA
               |-------------------|-------------------|
               |                                       |   H.UFAT
               |                                       |
               |                                       |
               |          User Attribute Area          |
               |                                       |
               |                                       |
               |                                       |
               |---------------------------------------|   S.HDHD

   Ident Area
               |---------------------------------------|
               |                                       |   I.FNAM
               |--                                   --|
               |               File Name               |
               |--                                   --|
               |                                       |
               |---------------------------------------|
               |               File Type               |   I.FTYP
               |---------------------------------------|
               |            Version Number             |   I.FVER
               |---------------------------------------|
               |            Revision Number            |   I.RVNO
               |---------------------------------------|
               |                                       |   I.RVDT
               |--                                   --|
               |             Revision Date             |
               |--                                   --|
               |                                       |
               |-------------------|                 --|
     I.RVTI    |                   |                   |
               |--                 |-------------------|





               |                                       |
               |--           Revision Time           --|
               |                                       |
               |-------------------|                 --|
     I.CRDT    |                   |                   |
               |--                 |-------------------|
               |                                       |
               |--                                   --|
               |             Creation Date             |
               |--                                   --|
               |                                       |
               |---------------------------------------|
               |                                       |   I.CRTI
               |--                                   --|
               |             Creation Time             |
               |--                                   --|
               |                                       |
               |---------------------------------------|
               |                                       |   I.EXDT
               |--                                   --|
               |            Expiration Date            |
               |--                                   --|
               |                                       |
               |-------------------|                 --|
               |     (not used)    |                   |
               |-------------------|-------------------|   S.IDHD

     Map Area
               |-------------------|-------------------|
     M.ERVN    |   Extension RVN   |  Ext. Seg. Num.   |   M.ESQN
               |-------------------|-------------------|
               |         Extension File Number         |   M.EFNU
               |---------------------------------------|
               |       Extension File Seq. Num.        |   M.EFSQ
               |-------------------|-------------------|
     M.LBSZ    |  LBN Field Size   | Count Field Size  |   M.CTSZ
               |-------------------|-------------------|
     M.MAX     | Map Words Avail.  | Map Words in Use  |   M.USE
               |-------------------|-------------------|   S.MPHD
               |                                       |   M.RTRV
               |                                       |
               |                                       |
               |          Retrieval Pointers           |
               |                                       |
               |                                       |
               |                                       |
               |---------------------------------------|
               |         File Header Checksum          |   H.CKSM
               |---------------------------------------|