INT 2F U - DOS 4.x internal - SET DOS VERSION NUMBER TO RETURN                  
	AX = 122Fh
	DX = DOS version number (0000h = return true DOS version)
Notes:	not available under DR DOS 5.0 or 6.0, or Novell DOS 7
	supported by FREEVER.COM, a freeware DOS version faking TSR(Terminate and Stay Resident) A program which remains in memory after terminating in order to provide services to other programs or the user.  The name comes from the name of the DOS function call used to remain in memory after termination. by Matthias
SeeAlso: INT 21/AH=30h,INT 21/AX=3306h,INT 2F/AX=E000h"SETDRVER"