UPDATING THE SCREEN OF A WORD PROCESSING TERMINAL WHICH IS EMULATING A DATA PROCESSING TERMINAL.

In a great many data processing systems, it has become conventional to update or change the data processing terminal screen every time a change is made in a single line or phrase to be displayed on the terminal. On the other hand, conventional text processing equipment display terminals do not operate in this fashion. They usually have to update the entire screen each time a single word or line is updated under processor control. Thus, when a text processing terminal functions as the emulation of a data processing terminal and has access to the data proceswsing data stream, it will find a data stream content architecture which is designed to update the display each time a single word or line is changed. Because this would be a very inefficient operation for a text processing terminal in view of the foregoing, the capability is provided within a text processing terminal to operate so as to update the screen only where required.