Character Based Screens isCOBOL can run applications with character based screens (green screens, text mode screens) on hardware terminals and terminal emulators. By default, isCOBOL emulates character based screens using graphical resources. This behavior produces an error if working on terminals that don’t include a graphical interface (dumb terminals and terminal emulators). The error returned is: No X11 DISPLAY variable was set, but this program performed an operation which requires it. To avoid this error and enable an application to use the terminal as the screen, isCOBOL takes advantage of CHARVA, a Java Windowing Toolkit for Text Terminals. See Using CHARVA for more information.
