This document provides an introduction to a course on pervasive computing. It discusses Mark Weiser's original vision of pervasive computing and how critical hardware is now available to begin pursuing this vision. Examples of pervasive computing projects at universities and in industry are provided. The goal of the paper that is the basis of this document is to understand the challenges in computer systems research posed by pervasive computing, by examining its relationship to distributed systems and mobile computing and identifying key research problems.

1. CS 6910 – Pervasive Computing
Section 0.A:
Introduction to Pervasive Computing
Dr. Leszek Lilien
Department of Computer Science
Western Michigan University
Slides based on the article “Pervasive Computing: Vision and Challenges”
by Prof. M. Satyanarayanan, Carnegie Mellon University,
IEEE Personal Communications, 2001
[Possible mistakes and omissions are all mine. – LTL]
Slides are © 2007 by Leszek T. Lilien
Requests to use original slides for non-profit purposes will be gladly granted upon a written request.

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© 2007 by Leszek T. Lilien
Based on: M. Satyanarayanan, “Pervasive Computing: Vision and Challenges,” IEEE Personal Communications, 2001
1. Introduction
 Vision of pervasive computing /ubiquitous
computing [Mark Weiser, 1991]
 ‘‘The most profound technologies are those that
disappear. They weave themselves into the fabric of
everyday life until they are indistinguishable from it.’’
 The essence of that vision:
 Creation of environments saturated with computing and
communication capabilities, yet gracefully integrated with
human users
 A vision too far ahead of its time (1991)
 The required hardware technology simply did not exist
 The implementation attempted by Weiser and his
colleagues at Xerox PARC fell short

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© 2007 by Leszek T. Lilien
Based on: M. Satyanarayanan, “Pervasive Computing: Vision and Challenges,” IEEE Personal Communications, 2001
Introduction (2)
 Critical hardware elements of pervasive computing are now
(2001) available
 Are now viable commercial products
 Examples:
 Handheld computers / wearable computers
 Wireless LANs
 Sensing devices
 Control appliances
 We can begin the quest for pervasive computing vision.
 Examples of pervasive computing projects
 At universities:
 Project Aura at Carnegie Mellon / Endeavour at UC Berkeley
 Oxygen at MIT / Portolano at Washington
 In the industry:
 AT&T Research in Cambridge, U.K.
 IBM TJ Watson Research Center

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© 2007 by Leszek T. Lilien
Based on: M. Satyanarayanan, “Pervasive Computing: Vision and Challenges,” IEEE Personal Communications, 2001
Introduction (3)
 The goal of this paper:
Understand the challenges in computer systems
research posed by pervasive computing
 Outline:
 Relationship of pervasive computing to the closely-
related fields of distributed systems and mobile
computing
 Two pervasive computing scenarios
 Why they are fiction rather than fact today.
 Selected key research problems
 With focus on computer systems issues
 Avoiding other areas important to pervasive computing
 E.g., human-computer interaction, expert systems, software
agents

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© 2007 by Leszek T. Lilien
Based on: M. Satyanarayanan, “Pervasive Computing: Vision and Challenges,” IEEE Personal Communications, 2001
2. Related Fields:
Pervasive Computing vs.
Distributed Systems & Mobile Computing
 Evolutionary history of pervasive computing
 Distributed systems (DIST)
 Mobile computing (MOBI)
 [LL:] Ad hoc systems is MOBI’s superset, VANs – its subset
 Pervasive computing (PERV)
 Technical problems in PC
 “Old” problems - already studied & solved at earlier evolution
steps
 Some earlier solutions apply directly for pervasive computing
 Some earlier solutions are inadequate for pervasive computing
 New problems - no obvious mapping to problems studied at
earlier evolution steps

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© 2007 by Leszek T. Lilien
Based on: M. Satyanarayanan, “Pervasive Computing: Vision and Challenges,” IEEE Personal Communications, 2001
Pervasive Computing vs. Distributed Systems & Mobile Computing (2)
 Next:
 Sort out complex intellectual relationship
 Between problems/solutions for DIST, MOBI, PERV
 Develop a taxonomy of research issues for each
phase of the evolution (DIST -> MOBI -> PERV)

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© 2007 by Leszek T. Lilien
Based on: M. Satyanarayanan, “Pervasive Computing: Vision and Challenges,” IEEE Personal Communications, 2001
Pervasive Computing vs. Distributed Systems & Mobile Computing (3)
2.1. Distributed Systems
 Distributed Systems
 Any computers connected by any networks
 [The paper: Intersection of personal computers and LANs]
 Research from the mid-1970’s through the early 1990’s
 Created a conceptual framework and algorithmic base
 Enduring value in all work involving >= 2 computers connected by
a network — whether mobile or static, wired or wireless, sparse or
pervasive
 Solutions from DIST
 Span many areas that are foundational to pervasive
computing
 Well codified in textbooks (e.g.,: [8, 19, 20])

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© 2007 by Leszek T. Lilien
Based on: M. Satyanarayanan, “Pervasive Computing: Vision and Challenges,” IEEE Personal Communications, 2001
Pervasive Computing vs. Distributed Systems & Mobile Computing (4)
Distributed Systems (2)
 Specific subarea solutions for DIST
 Remote communication
 Incl. protocol layering, remote procedure call [3], use of
timeouts, use of end-to-end arguments in placement of
functionality [28]
 Fault tolerance
 Incl. atomic transactions, distributed and nested transactions,
two-phase commit [13]
 High availability
 Incl. optimistic and pessimistic replica control [9], mirrored
execution [4], optimistic recovery [37]
 Remote information access
 Incl. caching, function shipping, distributed file systems,
distributed databases [30]
 Security
 Incl. encryption-based mutual authentication and privacy [23]