Abstract: An existing input and output system for inputting data via an emulator screen requires some degree of skill. A current mainstream web-browser-based input and output system that simply replaces such an existing system eliminates the advantage of various operations supported by the existing system. These input and output systems of different types are appropriately switched or simultaneously displayed depending upon the user or the usage environment. Two input and output screens on which a single system is operated are appropriately switched or simultaneously displayed by recording data input to a terminal and data received from the outside in a log file and storing the input data and the received data in display data storage parts for these two types of display screens.