Information Access and Connectivity Richard N. Taylor University of California, Irvine

Key Insights and Motivator *Software is a complex information product –a web of artifacts, processes, stakeholders *Software is but one kind of complex information product: –the technologies developed to support its creation and evolution can be used and adapted to support other kinds of complex information products (CIPs) –research to support other CIPs can be adapted and extended to support software

Evolution of the World Wide Web The “Berners-Lee” Web ( ) –Exponential Web growth threatened the Internet –Protocols assumed a direct connection between browser and server no awareness of caching, proxies or spiders no guidance for protocol extensions The modern WWW (1995-present) –Key differences, reflecting software engineering influences The model software architecture HTTP/1.1 URIs WebDAV –Key driver in evolution: enabling the Web to support “global software engineering”

Participants, Citations, and Products HTTP/1.1 protocol specification –Hypertext Transfer Protocol -- HTTP/1.1. (Fielding, Gettys, Mogul, Frystyk, Berners-Lee, Masinter, Leach). Internet Draft Standard RFC 2616, June Obsoletes RFC URI specification –Uniform Resource Identifiers (URI): Generic Syntax. (Berners-Lee, Fielding, Masinter). Internet Draft Standard RFC 2396, August –Relative Uniform Resource Locators. (Fielding). Internet Proposed Standard RFC 1808, June WebDAV protocol specification –HTTP Extensions for Distributed Authoring -- WebDAV. (Yaron Goland, Jim Whitehead, Asad Faizi, Steve Carter, Del Jensen) Internet Draft Standard RFC February –WebDAV: IETF Standard for Collaborative Authoring on the Web (E. James Whitehead, Jr., Meredith Wiggins) IEEE Internet Computing, Vol. 2, No. 5, September/October, 1998, pages Apache web server (55% of world market share) –The Apache HTTP Server Project (Fielding, Kaiser). IEEE Internet Computing, 1(4), July-Aug –Shared Leadership in the Apache Project. (Fielding). Communications of the ACM, 42(4), April 1999, pp

Allied Fields and Science Base Software architecture: source of the fundamental model for how the modern WWW is built –“Representational state transfer” Human-computer interaction: importance of the user’s perception of latency Hypermedia: source of many core concepts and a primary usage mode The network protocol stack Configuration management CSCW: collaborative authoring; concurrency control Software engineering environments: data integration; application interoperability

Sample Directions Near-term: Improved Web-based development of complex information products –Whether for global software engineering, aircraft design, advertising campaigns, curricula,... –Sample Issues Linking all artifacts, tools, and processes Management of artifacts and relationships over time Distributed change management, awareness, & task coordination Longer-term: “Next-generation WWW”: –Anytime, anywhere knowledge of what you need to know to accomplish your purposes, and ability to interact in that context.

Anytime, Anywhere Information & Interaction A software engineering use: software “maintenance” –Integration of all artifacts involved all developers all deployed versions all users the usage context –Applied recursively through systems-of-systems –To enable Awareness, effective update, assessment, monitoring, enhancement, integration,... Some non-software engineering uses (with strong overlap in the fundamental issues): –Crisis management systems– Process control –World-wide, just-in-time everything– Logistics –Air traffic control– Medical informatics

Science & Technology Base Event-based systems/implicit notification Software architectures Task models Protocols Names & namespaces Information meta-models Security Information Retrieval Information theory Performance models Wireless technologies Economics: incremental deployment, network effects

A Few Challenges & Contribution Areas Scale –Large numbers of event sources, event consumers, types of information, amounts of information --- constantly changing How do you describe this? Reason about it? Deal with it? –Geographical distribution --- latency issues Observation, experimentation, evaluation –How do you do this, on such a scale, with such dynamism? Usage –Information description, recognition, search, mining –Interface design; information overload Assurances: quality, reliability, availability,... Public policies –e.g., Taxation, safety, conflicts in nations’ laws