INT 2F - FreeDOS - FDAK-DDT - INSTALLATION CHECK / STATUS CHECK                 
	AX = 12FFh
	BL = 00h
Return: AL = DDh if installed
	    BH = state (00h disabled, nonzero enabled)
	    BL = readonly flag (00h writable, nonzero read-only)
Program: FDAK-DDT is the FreeDOS Alternative Kernel Device Drivers Testing
	  release by Yury A. Semenov
SeeAlso: AX=12FFh/BL=07h