Format of SHARE.EXE lock record:

Offset  Size    Description
 00h    WORD    offset in SHARE's DS of next lock table in list
 02h    DWORD   offset in file of start of locked region
 06h    DWORD   offset in file of end of locked region
 0Ah    DWORD   pointer to System File Table entry for this file
 0Eh    WORD    ??? 0 appears to mean 'in use'