The Digital Information Revolution: The Era of Immediacy Michael B. Spring May 2011 The Digital Information Revolution: the Era of Immediacy Table of Contents Table of Contents .................................................................................................................................................. ii Chapter I: Introduction ................................................................................................................ 1 Origins of This Book ............................................................................................................................................ 1 Audience for this Book ......................................................................................................................................... 2 The Author’s Perspective ..................................................................................................................................... 2 Acknowledgments ................................................................................................................................................ 4 Organization of the Book ...................................................................................................................................... 5 Chapter II: History ........................................................................................................................ 6 Introduction .......................................................................................................................................................... 6 A Look Back at Photography and Telecommunications ....................................................................................... 6 The Development of Distributed Computing ........................................................................................................ 8 Networking.................................................................................................................................................. 8 Affordable Personal Computing .................................................................................................................. 9 Accessible Computing............................................................................................................................... 10 Ubiquitous computing ............................................................................................................................... 11 A Selective History of Computers and Networking ............................................................................................ 11 The Evolution of the Internet .............................................................................................................................. 13 The Emergence of the World Wide Web ............................................................................................................ 15 The Magnitude of Change .................................................................................................................................. 17 Processing ................................................................................................................................................. 18 Storage ...................................................................................................................................................... 19 Transmission ............................................................................................................................................. 19 Conclusion .......................................................................................................................................................... 20 Chapter III: Information ............................................................................................................... 21 Introduction ........................................................................................................................................................ 21 A Common Sense Understanding ............................................................................................................. 22 Information as a Human Phenomenon ...................................................................................................... 22 Information in Context ....................................................................................................................................... 23 Communication: Oral and Symbolic.................................................................................................................. 25 Measuring Information ....................................................................................................................................... 27 Probabilities, Entropy, and Information .................................................................................................... 28 Other Measures of Information ................................................................................................................. 31 Information as Commodity ................................................................................................................................. 33 Information and Noise ........................................................................................................................................ 33 The Process of Informing ................................................................................................................................... 34 Chapter IV: Digital Information ................................................................................................... 37 Introduction ........................................................................................................................................................ 37 Key Advantages of Digital Information .............................................................................................................. 37 Error Correction ........................................................................................................................................ 38 Encryption ................................................................................................................................................. 42 Compression.............................................................................................................................................. 44 Some Limitations of Digital Information ............................................................................................................ 48 Infrastructure Stability............................................................................................................................... 48 Decisions about fidelity ............................................................................................................................. 49 Chapter V: Technology Simplified ............................................................................................ 52 Introduction ........................................................................................................................................................ 52 M.B. Spring ii 6/1/2011 The Digital Information Revolution: the Era of Immediacy Selected Definitions ............................................................................................................................................ 54 Trends in Technology ......................................................................................................................................... 58 Digitization................................................................................................................................................ 59 Accommodation ........................................................................................................................................ 60 Standardization .......................................................................................................................................... 61 Objectification ........................................................................................................................................... 62 Integration ................................................................................................................................................. 63 Distribution ............................................................................................................................................... 65 The Technology of the World Wide Web: A Simplified Perspective ................................................................. 67 The Basic Web .......................................................................................................................................... 68 A Unique Name for Each Information Resource ............................................................................ 68 A Procedure for Accessing Information .......................................................................................... 69 A Language for Representing Resources ........................................................................................ 70 The Evolution of the Web ......................................................................................................................... 72 Technical Evolution of the System ................................................................................................. 72 The Evolution