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Format of DOS 4+ system file tables and FCB tables:

Offset  Size    Description
 00h    DWORD   pointer to next file table
 04h    WORD    number of files in this table
 06h  3Bh bytes per file
        Offset  Size    Description
         00h    WORD    number of file handles referring to this file
         02h    WORD    file open mode (see AH=3Dh)
                        bit 15 set if this file opened via FCB
         04h    BYTE    file attribute
         05h    WORD    device info word (see AX=4400h)
         07h    DWORD   pointer to device driver header if character device
                        else pointer to DOS Device Control Block (see AH=32h)
         0Bh    WORD    starting cluster of file
         0Dh    WORD    file time in packed format (see AX=5700h)
         0Fh    WORD    file date in packed format (see AX=5700h)
         11h    DWORD   file size
         15h    DWORD   current offset in file
        ---local file---
         19h    WORD    relative cluster within file of last cluster read
         1Bh    DWORD   number of sector containing directory entry
         1Fh    BYTE    number of dir entry within sector (byte offset/32)
        ---network redirector---
         19h    DWORD   pointer to REDIRIFS record
         1Dh  3 BYTEs   ???
        ------
         20h 11 BYTEs   filename in FCB format (no path/period, blank-padded)
         2Bh    DWORD   (SHARE.EXE) pointer to previous SFT sharing same file
         2Fh    WORD    (SHARE.EXE) network machine number which opened file???
         31h    WORD    PSP segment of file's owner (see AH=26h)
         33h    WORD    offset within SHARE.EXE code segment of
                        sharing record (see below)  0000h = none
         35h    WORD    (local) absolute cluster number of last cluster read
                        (redirector) ???
         37h    DWORD   pointer to IFS driver for file, 0000000h if native DOS