INT 2F - Kingswood 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. INTERFACE - COMPATIBILITY MODE
	AX = 3900h
Return: AL = status
	    00h not installed
	    FFh one or more TSRs using this interface is installed
		DX may be destroyed
Note:	this function is provided to that the multiplex number will appear used
	  to other programs
SeeAlso: AH=39h/BL=00h