Int 14 Fn 7E  - Fossil - Install An External Application Function          [S]

   AH = 7Eh
   AL = code assigned to external application (80h-BFh)
       80h reserved for communications FOSSIL
       81h video FOSSIL
       82h reserved for keyboard FOSSIL
       83h reserved for system FOSSIL
   ES:DX -> entry point

Return: AX = 1954h
   BL = code assigned to application (same as input AL)
   DH = 00h failed
        01h successful

See Also: AH=7Fh,AH=80h"FOSSIL",AX=8100h,AH=82h"FOSSIL",AH=83h"FOSSIL"