The GUI client uses the X Toolkit and Athena Widgets, and is called xlayer. Its main screen is shown in Figure 2. Note that the buttons across the top activate menus or actions. The owner and location should be filled in by the user. The buttons below that, ``Minimal Configuration'', ``Standard Configuration'', and ``Local Configuration'' will configure the subsets according to what we believe will be some popular setups. The rest of the window contains a list of the subsets. Clicking on the ``status'' box following each subset name will pop up a menu allowing the user to set what should be done with that subset. Clicking on the ``Description'' box following each subset name will pop up a description of what is in that subset.
Figure 2: GUI Client Mockup. Clicking on a description button pops up a box with the description of that subset.
If the user attempts to use a subset without first selecting the any dependent subsets, a dialog will indicate the problem and offer to select the missing subsets. Something similar will happen if a dependent subset is removed.
In typical usage, it is only necessary to fill in the owner and location fields, click on the ``Standard Configuration'' button, then ``Do it'', which will ask for a confirmation. Other less used functions are found in the pull-down menus at the top. This includes having the workstation not announce itself to Athena Operations, and saving and restoring the configuration from a file. The wording used to describe the various privacy options must be considered very carefully so that most people will choose not to exercise these options.
This client will know how to read the subset configuration files to initialize the subset descriptions. However, it will perform all of its real work by running layer_athena, the regular client, as a sub-process.