INT 16 U - PCIBM PC Tools v5.1-5.5 PCShell 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. - GET ??? AX = FFDDh BX = 0002h Return: AL = 00h ??? 01h ??? Note: PCShell v6.0+ displays the error message "Incorrect PCRUN version", awaits a keystroke, and aborts the current process