INT 2F U - Biologic HRAMDEV.SYS - 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.
	AX = A189h
	BX = subfunction
	    0000h set ???
	    0001h remove ???
	    0002h get status ???
	    0003h enable ???
	    0004h disable ???
	    0005h set ??? flag
	    0006h clear ??? flag
	    0007h set ??? flag
	    0008h clear ??? flag
	    0009h set ???
	ES:DI -> function-specific arguments
		if func 0000h: 20-byte buffer containing ???
		if func 0001h: 20-byte buffer for returned ???
		if func 0002h: 16-byte buffer for returned ???
		if func 0009h: WORD containing ???
Return: BX = A189h if installed
	AH = status
	    00h successful
	    FFh failed or invalid function number
Program: HRAMDEV.SYS is a part of the shareware package HRAM by Biologic which
	  provides improved high memory access under MS-DOS 5.0
Note:	functions 00h and 01h use a stack of four entries; function 01h always
	  removes the values stored with the most recent function 00h call
	  which has not yet been matched with a function 01h call.