INT 7A - IBMInternational Busiuness MachinesInternational Busiuness Machines) A hardware, software and other service technology company founded in 1911. 3270 Workstation Program 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. - HOST SERVICES
	AH = 09h
	BX = request type (4000h async, 8028h synchronous)
	CX = 0000h
	DX = ID of MFIC
	AL = service (see #03837)
	ES:DI -> control block


(Table 03837)
Values for 3270 Workstation Program host service:
 01h	connect to host
 02h	disconnect from host
 03h	read DFT structured data from host
 04h	write DFT structured data to host
 05h	create a host buffer