INT 60 U - Agfa TTSR.EXE - 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 = 899Bh BX = function 0001h installation check Return: BX = 899Bh if installed 0002h ??? 0003h ??? ??? Return: ??? Note: TTSR.EXE is found in FotoLook 2.09 (16-bit), which is available from agfa.com; it appears to provide DOS ASPI support !!!