INT 16 U - TextWare TWTSR - 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 = 3577h CX = function 00CBh ??? Return: AX = 0000h BX = 0000h DX:CX -> ??? 00CCh uninstall Return: AX = status 0000h successful FFFDh unable to unload because vectors taken 00CDh ??? Return: AX = 0000h BX = 0000h DX:CX -> ??? other Return: AX = 5345h ('SE') Program: TWTSR is a TSR(Terminate and Stay Resident) A program which remains in memory after terminating in order to provide services to other programs or the user. The name comes from the name of the DOS function call used to remain in memory after termination. which allows the TextWare hypertext browser to be popped up via hotkey SeeAlso: AX=D724h