Information Access and Connectivity

Richard N. TaylorUniversity of California, Irvine

taylor@uci.eduhttp://www.ics.uci.edu/~taylor/

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 (1989-1994+)– 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 1999. Obsoletes RFC 2068.

• URI specification– Uniform Resource Identifiers (URI): Generic Syntax. (Berners-Lee, Fielding, Masinter). Internet Draft

Standard RFC 2396, August 1998. – Relative Uniform Resource Locators. (Fielding). Internet Proposed Standard RFC 1808, June 1995.

• WebDAV protocol specification– HTTP Extensions for Distributed Authoring -- WebDAV. (Yaron Goland, Jim Whitehead, Asad Faizi,

Steve Carter, Del Jensen) Internet Draft Standard RFC 2518. February 1999. – 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 34-40.

• Apache web server (55% of world market share)– The Apache HTTP Server Project (Fielding, Kaiser). IEEE Internet Computing, 1(4), July-Aug. 1997. – Shared Leadership in the Apache Project. (Fielding). Communications of the ACM, 42(4), April 1999,

pp. 42-43.

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