INT 2F - AD-DOS - INSTALLATION CHECK
AX = 0C00h
Return: AL = FF if installed
BX = 4144H  ('AD')
CX = 2D44H  ('-D')
DX = 4F53H  ('OS')
Notes:  AD-DOS is the DOS version of the After Dark screen blanker for
MS Windows
AH=0Ch is the default multiplex number (there is one report of a
version with AH=C0h as default)

See also: 2F0C01

2F0C00 - AD-DOS - INSTALLATION CHECK