GroupKit User Manual - An End User's View

Before delving into the details of how to build GroupKit applications, we'll first walk through how an end user would run some of the existing applications included in the distribution. This will give you a chance to make sure things are set up on your own system, as well as introduce some important concepts about groupware programs.

We'll assume that GroupKit has already been compiled and installed on all participating systems, with a registrar process running. If GroupKit has not yet been installed, you can install it yourself by following the step by step installation instructions in the README file in the software distribution.

Starting a Session Manager

In GroupKit, you don't run programs directly, but invoke them via another program called a session manager. The session manager is used to locate other people in your work community running GroupKit programs, and connect your programs up to them, or to start up programs of your own. Running your programs together with other people is called a conference or session. GroupKit actually comes with several different session managers, but we'll use one called the Open Registration session manager.

To start it, do the following:

The first time you start up, the session manager may ask you some questions about yourself, such as your name, and store this in a preferences file It should then show the window in Figure XX (if you have problems, make sure that you have a registrar process running). The "Conferences" pane on the left shows the names of any running conferences. Selecting one will show who is in the conference in the "Participants" pane on the right. The "Conferences" menu contains a list of known GroupKit applications and lets you start up new groupware sessions.

Figure XX. Open Registration session manager.

Creating a New Conference

Assuming there are no conferences already running which we could join, let's create a new conference. We'll use a program called "Simple Sketchpad", which acts like a shared whiteboard, allowing several users to simultaneously draw freehand on a canvas.

To create it, pull down the "Conferences" menu in the session manager and select "Simple Sketchpad". A dialog box will appear, shown in Figure XX. This dialog box allows you to give your conference a name (by default it is just the name of the application) which will identify it to other users. When you've picked a name, click the "Create" button.

Figure XX. Conference naming dialog.

At this point, you'll see the name of the conference added to the "Conferences" pane in the session manager, and the Simple Sketchpad program will come up in its own window, as shown in Figure XX. You can draw on the canvas using the left mouse button. The menus let you clear the canvas, exit the program, find out about other participants in the conference, and get information about both GroupKit and the Simple Sketchpad conference. Try it!

Figure XX. Simple Sketchpad conference.

Joining an Existing Conference

We'll now have another user join the conference you've created. Find someone else on another machine nearby, and get them to start up their own copy of the open.reg session manager. They should see the conference you've created, and clicking on it will show that you are a participant in it. If you are just trying GroupKit out by yourself, create another open.reg on the same machine, and pretend you are a different person by changing your name to a new one in the entry box on the bottom.

To join the conference from their session manager, the other participant can double-click the name of the conference. This will add their name to the list of participants, and also bring up a window with their own copy of the Simple Sketchpad program. You'll also see that any drawing that was done in the first copy of the program appears in the new copy.

You'll now find that both people can draw at the same time, and that any drawings made by one user immediately appear on the screens of the other user. You'll also see a small cursor called a telepointer, which tracks the location of the other user's mouse cursor as they move around the window. More than two people can be in this conference and others can join and participate through their own session managers.

When done, you can select "Quit" or "Exit" from the "File" menu of the Simple Sketchpad program to leave the conference. Your copy of the program will disappear, and you'll see your name removed from the list of conference participants in the session manager.

What's Really Happening Inside

To understand what is going on, lets take a step back. As you've noticed, GroupKit consists of a number of different processes, which are illustrated in Figure XX. There is a central process called the registrar, a "daemon" that should already be running on your system. Its job is to keep track of what conferences are running and who is joined to them. Each user runs a session manager, such as open.reg, which connects up to the registrar. The session managers are used to create conferences (such as our Simple Sketchpad) which again run as separate processes. As other users join conferences through their own session managers, GroupKit opens up network connections between the conference processes, so that every process in a conference has a connection to every other process in a conference.

Figure XX. GroupKit process and communications architecture.

Other Applications

There are a number of other sample applications included with the GroupKit distribution which you should try out. Some of these are illustrated in Figure XX and include:

Figure XX. Some example GroupKit conference applications.

Important Concepts

There are several important points about GroupKit that have been illustrated so far.

GroupKit User Manual. Last updated March 16, 1998 by Mark Roseman.