pervasive com 1

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]