Embedded, Everywhere A Research Agenda for Networked Systems of Embedded Computers doc

Embedded, Everywhere A Research Agenda for Networked Systems of Embedded Computers Committee on Networked Systems of Embedded Computers Computer Science and Telecommunications Board Division on Engineering and Physical Sciences National Research Council NATIONAL ACADEMY PRESS Washington, D.C. NOTICE: The project that is the subject of this report was approved by the Gov- erning Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engi- neering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance. Support for this project was provided by the Defense Advanced Research Projects Agency and the National Institute of Standards and Technology. Any opinions, findings, conclusions, or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the sponsor. Moreover, the views, opinions, and findings contained in this report should not be construed as an official Department of Defense position, policy, or decision, unless so desig- nated by other official documentation. Library of Congress Control Number: 2001093511 International Standard Book Number 0-309-07568-8 Additional copies of this report are available from: National Academy Press 2101 Constitution Avenue, N.W. Box 285 Washington, DC 20055 800/624-6242 202/334-3313 (in the Washington metropolitan area) http://www.nap.edu Copyright 2001 by the National Academy of Sciences. All rights reserved. Printed in the United States of America The National Academy of Sciences is a private, nonprofit, self-perpetuating soci- ety of distinguished scholars engaged in scientific and engineering research, dedi- cated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Bruce M. Alberts is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its mem- bers, sharing with the National Academy of Sciences the responsibility for advis- ing the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Wm. A. Wulf is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Kenneth I. Shine is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sci- ences in 1916 to associate the broad community of science and technology with the Academy’s purposes of furthering knowledge and advising the federal gov- ernment. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in pro- viding services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Bruce M. Alberts and Dr. Wm. A. Wulf are chairman and vice chairman, respectively, of the National Research Council. National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council COMMITTEE ON NETWORKED SYSTEMS OF EMBEDDED COMPUTERS DEBORAH L. ESTRIN, University of California at Los Angeles, Chair GAETANO BORRIELLO, University of Washington ROBERT PAUL COLWELL, Intel Corporation JERRY FIDDLER, Wind River Systems, Inc. MARK HOROWITZ, Stanford University WILLIAM J. KAISER, Sensoria Corporation NANCY G. LEVESON, Massachusetts Institute of Technology BARBARA H. LISKOV, Massachusetts Institute of Technology PETER LUCAS, Maya Design Group DAVID P. MAHER, InterTrust Technologies Corporation PAUL M. MANKIEWICH, Lucent Technologies RICHARD TAYLOR, Hewlett-Packard Laboratories JIM WALDO, Sun Microsystems, Inc. Staff LYNETTE I. MILLETT, Program Officer (Study Director beginning September 2000) JERRY R. SHEEHAN, Senior Program Officer (Study Director through August 2000) SUZANNE OSSA, Senior Project Assistant v COMPUTER SCIENCE AND TELECOMMUNICATIONS BOARD DAVID D. CLARK, Massachusetts Institute of Technology, Chair DAVID BORTH, Motorola Labs JAMES CHIDDIX, AOL Time Warner JOHN M. CIOFFI, Stanford University ELAINE COHEN, University of Utah W. BRUCE CROFT, University of Massachusetts at Amherst SUSAN L. GRAHAM, University of California at Berkeley JUDITH HEMPEL, University of California at San Francisco JEFFREY M. JAFFE, Bell Laboratories, Lucent Technologies ANNA KARLIN, University of Washington MICHAEL KATZ, University of California at Berkeley BUTLER W. LAMPSON, Microsoft Corporation EDWARD D. LAZOWSKA, University of Washington DAVID LIDDLE, U.S. Venture Partners TOM M. MITCHELL, WhizBang! Labs, Inc. DONALD NORMAN, UNext.com DAVID A. PATTERSON, University of California at Berkeley HENRY (HANK) PERRITT, Chicago-Kent College of Law BURTON SMITH, Cray, Inc. TERRY SMITH, University of California at Santa Barbara LEE SPROULL, New York University MARJORY S. BLUMENTHAL, Executive Director HERBERT S. LIN, Senior Scientist ALAN S. INOUYE, Senior Program Officer JON EISENBERG, Senior Program Officer LYNETTE I. MILLETT, Program Officer CYNTHIA PATTERSON, Program Officer JANET BRISCOE, Administrative Officer MARGARET HUYNH, Senior Project Assistant SUZANNE OSSA, Senior Project Assistant DAVID DRAKE, Project Assistant DAVID PADGHAM, Research Assistant BRANDYE WILLIAMS, Office Assistant vi Preface C ontinued advances in information technologies are enabling a growing number of physical devices to be imbued with comput- ing and communications capabilities. Aircraft, cars, household appliances, cellular telephones, and health monitoring devices all contain microprocessors that are being linked with other information processing devices. Such examples represent only the very beginning of what is possible. As microprocessors continue to shrink, wireless radios are also becoming more powerful and compact. As the cost of these and related technologies continues to decrease, computing and communications tech- nologies will be embedded into everyday objects of all kinds to allow objects to sense and react to their changing environments. Networks comprising thousands or millions of sensors could monitor the environ- ment, the battlefield, or the factory floor; smart spaces containing hun- dreds of smart surfaces and intelligent appliances could provide access to computational resources. Getting to this point will not be easy. Networks of embedded com- puters pose a host of challenges qualitatively different from those faced by more traditional computers or stand-alone embedded computers be- cause they will be more tightly integrated with their physical environ- ments, more autonomous, and more constrained in terms of space, power, and other resources. They will also need to operate, communicate, and adapt in real time, often unattended. Enabling such innovation will require that a number of research challenges be overcome. How can large numbers of embedded computing devices assemble themselves seam- vii viii PREFACE lessly into an integrated network? How can their performance be guaran- teed? How can social issues raised by the advent of more pervasive information collection and processing—for example, concerns about pri- vacy, robustness, and usability—be addressed? CHARGE TO THE COMMITTEE To improve understanding of these issues and help guide future re- search endeavors, the Defense Advanced Research Projects Agency (DARPA) and the National Institute of Standards and Technology (NIST) asked the Computer Science and Telecommunications Board (CSTB) of the National Research Council (NRC) to conduct a study of networked systems of embedded computers (EmNets) that would examine the kinds of systems that might be developed and deployed in the future and iden- tify areas in need of greater investigation. This report identifies opportu- nities for the use of EmNets, examines the ways EmNets differ from more traditional systems, and delineates the research topics that need to be addressed. The objective is to develop a research agenda that could guide federal programs related to computing research and inform the research community (in industry, universities, and government) about the chal- lenging needs of this emerging research area. This report examines both issues related to components of embedded computers—such as hardware needs, operating systems, programming capabilities, and human inter- faces—and systems-level issues resulting from the interconnection of multiple embedded computers—system architectures, coordination, ad- aptation, reliability, security, safety, interoperability, stability, and guar- anteed performance. To that end, the committee attempted to answer questions such as the following: • What are networked systems of embedded computing systems? How do networks of embedded computers differ from more traditional computer networks? How do these differences affect research needs? • What types of applications could arise from greater networking of embedded systems? What are the general characteristics of different ap- plications? What would be the benefits and capabilities of such systems? • How can systems of interconnected embedded processors be more easily designed, developed, and maintained? How can system reliability, safety, operability, and maintainability be ensured in networked systems? How do such considerations differ for embedded and more traditional forms of computing? • What kinds of advances are needed in enabling component tech- nologies, such as hardware devices, operating systems, and communica- tions networks, to make EmNets possible and more capable? PREFACE ix • What types of user interfaces are needed to allow users to interact with and to program systems composed of large numbers of inter- connected embedded systems? How do these requirements differ for different kinds of users (experts, novices, system integrators)? What types of “programming” will consumers be expected to perform? • How can the stability and effectiveness of interconnected systems of embedded computers be assured if individual components come from a wide variety of developers and use a variety of hardware and software platforms, some of which may run the latest versions of the software, and others of which may be several generations behind? COMMITTEE COMPOSITION AND PROCESS To conduct the study, CSTB assembled a committee of 15 members from industry and academia with expertise in areas of apparent impor- tance to EmNets, such as computing devices, very-large-scale integrated circuit technology, networking, wireless communications, embedded op- erating systems, software safety, distributed computing, programming languages, human-computer interfaces and usability, and computer sys- tem security. 1 Several committee members brought with them a familiar- ity with federal research programs related to EmNet technologies and provided invaluable insight into the challenges of organizing research programs in this area. Several committee members changed their organi- zational affiliation during the course of the study, attesting to the dy- namic nature of this field. Indeed, because of growing commercial inter- est in ubiquitous or pervasive computing technology, two of the original committee members, Walter Davis from Motorola and Ajei Gopal from IBM, were unable to continue their participation in the project. The committee met six times between December 1999 and March 2001 to plan its course of action, solicit testimony from relevant experts, delib- erate its findings, and draft its final report. It continued its work by electronic communications into the spring of 2001. During the course of the project, the committee heard from information technology researchers in industry and universities and from directors of government agencies involved in funding computing research (including research related to EmNets). 2 It also met with people involved in developing and deploying EmNets to serve a range of missions, from controlling lighting and heat- ing systems in office buildings and automating manufacturing lines, to 1 See Appendix A for biographies of committee members. 2 See Appendix B for a list of briefers to the committee. x PREFACE monitoring the health of astronauts in space and of patients in emergency rooms. The committee also gathered information on major initiatives to pursue research on ubiquitous and pervasive computing, and it collected data on microprocessors, microcontrollers, wireless communications nodes, and their applications in order to track the emergence of an EmNet environment. ACKNOWLEDGMENTS As with any project of this magnitude, thanks are due to the many individuals who contributed to the work of the committee. First, thanks are due to the members of the committee itself, who volunteered consid- erable time during the course of the study to attend meetings, engage in e- mail and telephone discussions, draft sections of the report, and respond to comments from external reviewers. Beyond the committee, numerous persons provided valuable infor- mation through briefings to committee meetings: Andrew Berlin, Xerox Palo Alto Research Center; Stephen P. Boyd, Stanford University; Janusz Bryzek, Maxim Integrated Products, Inc.; David D. Clark, Massachusetts Institute of Technology; Alan Davidson, Center for Democracy and Tech- nology; Robert Dolin, Echelon Corporation; John Hines, National Aero- nautics and Space Administration; Rodger Lea, Sony Distributed Systems Laboratory; K. Venkatesh Prasad, Ford Research Laboratory; Jonathan Smith, University of Pennsylvania; Karen Sollins, National Science Foundation; and Keith Uncapher, Corporation for National Research Initiatives. Thanks are also due to those who sponsored the study. David Tennenhouse, formerly the director of the Defense Advanced Research Project Agency’s (DARPA) Information Technology Office (ITO) and now vice president of research at Intel Corporation, provided the original im- petus for the study, identifying networked systems of embedded comput- ers as a potentially revolutionary set of technologies and laying out a vision for the field. Shankar Sastry and Janos Sztipanovits ensured con- tinued DARPA support for the project as they expanded ITO’s research efforts in EmNets of different kinds. Sri Kumar, also of DARPA’s ITO, provided considerable guidance and input related to sensor networks. Jerry Linn, formerly of the Information Technology Lab at NIST, gener- ated interest and financial support from several laboratories within NIST. Other members of the Technology Policy Working Group also supported the concept of the study, even if they did not provide financial support. Many others also provided valuable input or services to the commit- tee that should not go unnoted. Martin Herman and Alden Dima of NIST provided relevant information about NIST programs near the end of the [...]... trustworthiness, and computational models) Research into all of the themes is required before EmNets can fulfill their potential Research in broadly relevant areas such as networking and usability that pervade many of the themes described below is also essential: • Predictability and manageability Methodologies and mechanisms for designing predictable, safe, reliable, manageable EmNets; • Adaptive self-configuration... Southern California; Gaurav Sukhatme of the University of Southern California; Scott Stadler of the Massachusetts Institute of Technology’s Lincoln Laboratory; Gregory J Pottie of the University of California at Los Angeles; and Steven T Sonka of the University of Illinois at Urbana-Champaign also provided background information to the committee Finally, the committee would like to acknowledge the work of. .. of Location, 167 Conducting Research on Models and Abstractions, 168 References, 171 6 CONCLUSIONS AND RECOMMENDATIONS: AN AGENDA FOR RESEARCH An EmNet-specific Research Agenda, 174 Predictability and Manageability, 175 Adaptive Self-configuration, 176 Monitoring and System Health, 177 Computational Models, 178 Network Geometry, 179 Interoperability, 180 Integration of Technical, Social, Ethical, and... creating a system that functions properly for the application domain while remaining understandable and manageable by human operators, users, and—in many cases—casual passersby, is a large challenge for EmNet designers As an example, consider a transportation information system based on EmNet technology Such a system will certainly be large in size and scale, possibly encompassing the entire highway system...PREFACE xi study process As she has done so many times in the past, Laura Ost, a free-lance editor, provided invaluable assistance in preparing the manuscript for review Jim Igoe, with the National Academies library, was helpful with background research Craig Kaplan of the University of Washington assisted with cover design Jeffrey Risberg of TIBCO Software, Inc.; Maja Mataric of the University of Southern... techniques and software, and traffic generators can all be shared among research programs when applicable, avoiding redundancy in those parts of the system where there is more certainty It is expected that this sharing and associated coordination needs can be supported by the various organizations and groups associated with federal information technology research and development LOOKING FORWARD , EmNets... (see Box 1.1) As computing has migrated from mainframe computers to minicomputers, personal computers, laptops, and, most recently, palmtop computers and information appliances, it has become more widespread and more a part of everyday life for millions Meanwhile, embedded computers have been used in automobiles, aerospace engineering, and military applications for quite some time Advances in networking... Recommendation 2 The Defense Advanced Research Projects Agency should encourage greater collaboration between its Information Technology Office and its Microelectronics Technology Office to enable greater experimentation Greater collaboration between these offices would facilitate rich and significant experimentation in EmNet-related areas 12 EMBEDDED, EVERYWHERE National Institute of Standards and Technology... integration of MEMS devices into EmNets Continuing research into operating systems for networks of embedded computers and into the development of software that has the required characteristics will also be necessary EmNets software will need to be tailorable to physical constraints and application requirements in deployment, be upgradable, have high availability, and be able to work with new hardware... handle the vast amounts of personal information that will be collected and implementing privacy policies once they are decided on is a large area ripe for research 7 EXECUTIVE SUMMARY Finally, and related to all of the above, EmNets will need to be usable by persons with little or no formal training Unfortunately, usability and safety often conflict, and decisions on trade-offs will need to be made . Assistant DAVID DRAKE, Project Assistant DAVID PADGHAM, Research Assistant BRANDYE WILLIAMS, Office Assistant vi Preface C ontinued advances in information. TIBCO Soft- ware, Inc.; Maja Mataric of the University of Southern California; Gaurav Sukhatme of the University of Southern California; Scott Stadler of the Massachusetts