INT A4 U - Right Hand Man - API(Application Program[ming] Interface) The defined set of calls which a program may make to interact with or request services of the operating system or environment under which it is running.  Because the inputs and outputs of the calls are well-defined, a program using the API can continue using the identical calls even if the internal organization of the program providing the API changes.
	AH = function number (v3.3 supports functions 00h-52h)
Return: CF set on error
	CF clear if successful
Program: Right Hand Man is a 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. desk-top utility originally by Red E Products
	  which has evolved into Futurus Team
Note:	this interrupt is only hooked while popped up
SeeAlso: INT 2F/AX=A4E0h