Running GO-Joe

To start a GO-Joe session, simply load the HTML file with the applet embedded into your browser environment. GO-Joe will prompt you for a username and password to use for the session, and will proceed to provide the X display to your host.

This session is almost identical to that provided by the system console, with a few differences, which are illustrated below.

DISPLAY Environment Variable

The $DISPLAY environment variable tells X clients where to contact your X server. Unlike most X solutions which set the $DISPLAY variable to point to your JavaStation, GO-Joe sets this variable to point to an alternate display on your host machine. For example, if your host is named "workstation" and the JavaStation is named "smile," you might expect the $DISPLAY variable to use smile:0 as its value. However, GO-Joe uses the hostname for its $DISPLAY variable value, in this case, workstation:1.

GO-Joe makes an additional optimization that can be somewhat confusing. In X parlance, if the $DISPLAY variable is set to unix:# the JavaStation client will attempt to connect using a local transport. For example, instead of using TCP/IP, it will connect using a named pipe. This connection is faster than using TCP/IP for JavaStation clients running on the same host. However, the unix:# value cannot be used if you run clients from different hosts.

Instead, use the following shell script to change the $DISPLAY variable to point to the hostname of your machine. This can be included in .profile file:

DISPLAY=`/bin/uname -n``expr $DISPLAY : `[^:]*\(:.*\)'`

This translates $DISPLAY from, for example, unix:3 to workstation:3 allowing X clients on other machines to successfully contact the GlobalHost loadable ddx module on the workstation host.

Using a Two-Button Mouse

X requires and assumes the availability of a three-button mouse. Most Java environments provide a two-button mouse. In the session, the left and right mouse buttons correspond to the left and right mouse buttons under X. GO-Joe maps the simultaneous pressing of both mouse buttons into a middle mouse button press under X.

The Mouse Arrow

Current AWT implementations provide only limited support for specifying the shape of the mouse arrow in the Java environment. For this reason, GO-Joe currently does not change the shape of the pointer arrow. This effect is a visual one only, as the X application will believe that the arrow has indeed changed shape.