INT E0 - GSX-86, GEM/1, GEM/2 - 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.
	CL = 73h
	CH = 04h
	DS:DX -> parameter block