Running GO-Joe

To start a GO-Joe session, load the HTML file with the GO-Joe applet into your Java environment. GO-Joe prompts you for a user name and password for the session, and after authentication, provides the X display on your Java desktop.

This session is almost identical to running an X session on the system console, with a few differences, which are described below.

DISPLAY Environment Variable

The $DISPLAY environment variable tells X clients where to contact your X server. GO-Joe sets this variable to point to an alternate display on your host machine. For example, if your UNIX host is named workstation and the Java device is named java, you might expect the $DISPLAY variable to set java:0 as its value. However, GO-Joe uses the host name 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 attempts to connect using a local transport. For example, instead of using TCP/IP, it connects using a named pipe. This connection is faster than using TCP/IP for 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 host name of your machine. This translates $DISPLAY from unix:3, for example, to workstation:3 enabling X clients on other machines to successfully contact GO-Joe on the workstation host. This can be included in the .profile file:

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

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 an X 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.

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 mouse arrow.