The Shared WhiteBoard: A Java Applet over Transis

Developed by Gadi Shamir

Many thanks to Ohad Rodeh for adding some improvements to this project and for helping me prepare this web page.

NOTE: Due to security restrictions (CS departement firewall) this demo cannot be invoked outside the CS departement at the Hebrew University. We are investigating ways to overcome this obstacle.

The distributed whiteboard applet is a virtual sketchbook for artists working at different, possibly distant geographic locations. Artists may join and leave the whiteboard at will. The underlying protocol ensures that all whiteboard artists see a consistent picture of their masterpiece, as if they were sketching on the same board. Shapes may be added to the whiteboard, dragged in it, or deleted from it at any time by each participant. Local changes applied to the whiteboard are disseminated through the Transis multicast service to all the whiteboard artists in a consistent manner.

Try launching the whiteboard now:
The whiteboard protocol is designed to deal with failures such as processor or link failures. Should a partition occur between whiteboard participants, two virtual copies of the whiteboard may coexist at the same time, accepting changes from connected members. Remerging of two whiteboard copies should not pose an obstacle, as long as a predefined merging rule is agreed upon (A trivial yet simple rule that is currently implemented could be: adopt the whiteboard with the largest number of shapes).

Information: Shared Whiteboard - A Java Application in the Transis Environment, lab project, 1996. postscript, gzipped postscript

Comments and bugs (welcome): gadish@cs.huji.ac.il.
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Last modified: Wed Mar 19 18:31:39 IST 1997