This is a simple "shell" application that grabs other windows and places them inside its own window. It is typically used with the mbone tools from LBL (wb, vic and vat) which provide a shared whiteboard, video and audio support. However, ssd is easily configured to use other conferencing tools.
Ssd is written in C, Tcl and Tk.
The screen layout of ssd.
This is an image of ssd running. The colours in the video windows are incorrect because vic was updating them as the screen capture was running. The layout shown is intended to fill half of the screen and leave the other half for the web browser.
Figure 1: A screenshot of ssd.
The list at the top of the window is a shared list of URLs. Users can submit URLs to it using the button in the bottom left corner of the window. Double-clicking on one of the URLs in the list will send the user's browser (either Netscape or Mosaic) to that URL and will also launch the browser if it has not already been launched.
The conference entry and floor control parts of ssd aren't visible because this is only a user's ssd window, not the (slightly different) session chairman's version. They would appear in place of the right hand side of the URL list.
Users who do not wish to create new sessions begin their sessions by starting ssd. They are then presented with a list of available conferences. (Advertised conferences are announced every ten seconds, so it may take that long for all of them to become listed).
When the user double-clicks on one of the conferences in the list, then their software will request entrance into that conference from the conference chairman.
Conference chairmen initiate sessions by starting ssd with the -master flag. As for normal users the chairman is presented with a list of available sessions. There is also an additional "Create Conference" button.
If the conference chairman chooses to create a new conference then they are prompted for a title for the conference:
Once a conference chairman has created their conference their conferencing applications are immediately launched. As chairman they have a number of extra controls in the top, right of their conference window:
The image shows the top part of a chairman's conference window. The right-hand listbox lists users who are requesting entry into the conference. If the chairman selects their name and chooses "Accept" or double-clicks on their name then that user will be sent details of the conference. If the chairman selects their name but instead chooses "Reject" then that user will be sent a rejection message.
When a user's software receives details of the conference on being accepted by the conference chairman then their conferencing window will immediately launch.
If a user becomes unruly, or there are too many users attempting to talk at once, then the conference chairman may choose to use the floor control system (by clicking on the button labelled "UFC" in the top right corner of their conference window). They are then presented with a list of users in the conference, each of which has a checkbox beside their name. If a checkbox is turned off then that user finds themself unable to transmit audio or to further draw on the shared whiteboard.
Once control of the conference has been regained the chairman may choose to relinquish the floor control system and return to the previous free-for-all style of conference.
There is also a KBS that periodically examines the number of users in the conference and for how long each of them has spoken (by logging data transmitted by vat according to the LBL Conference Bus standard) and under certain circumstances will make suggestions to the conference chairman about controlling the conference (e.g. whether to use the floor control facilities, etc.). This feature is intended as support for novice chairmen.
Any user may leave at any time by clicking on their "Quit" button.
The conference chairman may also leave by this method. Once the chairman has left the conference no new users may join the conference (since the chairman is the contact point that advertises the conference and allows new users entry into the conference by telling them the connection details).