IBM 3270 Information Display System

WSim simulates a 3270 terminal by maintaining an updated buffer or screen image for the terminal. The buffer can be modified by generated messages or by messages received from the system under test. For a message generated by a simulated 3270 terminal, WSim builds the message from the current state of the terminal buffer including any necessary orders in the data stream to be transmitted. For a received message, all commands and orders other than 3270 printer orders are processed and the terminal buffer is updated accordingly. WSim automatically maintains attribute bytes in the buffer that define different display or data entry fields.

For a complete list of the IBM® 3270 components WSim can simulate, see Defining WSim networks.