[Brown CS Talks] Brown CS Seminar: Phil Levis in room 506 on 7/17/02 at 12 pm.

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                              CS Seminar
                  The Department of Computer Science
			   BROWN UNIVERSITY

			      
			       presents

			      Phil Levis

		     EECS, University of Berkeley

		 Wednesday, July 17, 2002 at 12:00 PM

		       Room 506 (CIT 5th Floor)

	       

	   Mate: A Tiny Virtual Machine for Sensor Networks
 

			       Abstract

Composed of tens of thousands of tiny devices with very limited
resources (`motes'), sensor networks are subject to novel systems
problems and constraints. The large number of motes in a sensor
network means that there will often be some failing nodes; networks
must be easy to repopulate. Often there is no feasible method to
recharge motes, so energy is a precious resource. Once deployed, a
network must be reprogrammable although physically unreachable, and
this reprogramming can be a significant energy cost.


We present Mate, a tiny communication-centric virtual machine designed
for sensor networks. Mate's high-level interface allows complex
programs to be very short (under 100 bytes), reducing the energy cost
of transmitting new programs. Code is broken up into small capsules of
24 instructions, which can self-replicate through the network. Packet
sending and reception capsules enable the deployment of ad-hoc routing
and data aggregation algorithms. Mate's concise, high-level program
representation simplifies programming and allows large networks to be
frequently reprogrammed in an energy-efficient manner; in addition,
its safe execution environment suggests a use of virtual machines to
provide the user/kernel boundary on motes that have no hardware
protection mechanisms.



		   Host: Professor Ugur Cetintemel