Format of sharing record:

Offset  Size    Description
 00h    BYTE    flag
                00h free block
                01h allocated block
 01h    WORD    size of block
 03h    BYTE    ???
 04h    WORD    offset in SHARE's DS of lock record (see below)
 06h    DWORD   pointer to start of system file table chain for file
 0Ah    WORD    ???
 0Ch    var     ASCIZ full pathname