The problem with trees Many systems are organized hierarchically. The CERNDOC documentation system is an example, as is the Unix file system, and the VMS/HELP system. A tree has the practical advantage of giving every node a unique name. However, it does not allow the system to model the real world. For example, in a hierarchical HELP system such as VMS/HELP, one often gets to a lead on a tree such as: HELP COMPILER SOURCE_FORMAT PRAGMAS DEFAULTS only to find a reference to another leaf: Please see HELP COMPILER COMMAND OPTIONS DEFAULTS PRAGMAS and it is necessary to leave the system and re-enter it. What was needed was a link from one node to another, because in this case the information was not naturally organized into a tree. Tim Berners-Lee, Seeing With Fresh Eyes A City Is Not a Tree hierarchywww
Cool URIs don't change An Essay by Tim Berners-Lee www.w3.org What makes a cool URI? A cool URI is one which does not change. What sorts of URI change? URIs don't change: people change them. The User Interface of URLs www
Manifesto for Agile Software Development A Definition agilemanifesto.org We are uncovering better ways of developing software by doing it and helping others do it. Through this work we have come to value: Individuals and interactions over processes and tools Working software over comprehensive documentation Customer collaboration over contract negotiation Responding to change over following a plan That is, while there is value in the items on the right, we value the items on the left more. Deliver early and continuouslyWelcome changing requirementsSelf-organizing teamsTechnical excellence and good designAgility and sustainability+7 More agileprocesssoftware
Deliver early and continuously Our highest priority is to satisfy the customer through early and continuous delivery of valuable software.
Welcome changing requirements Welcome changing requirements, even late in development. Agile processes harness change for the customer's competitive advantage. A late change in requirements is a competitive advantage planning
Self-organizing teams The best architectures, requirements, and designs emerge from self-organizing teams.
Technical excellence and good design Continuous attention to technical excellence and good design enhances agility. craft
Agility and sustainability Agile processes promote sustainable development. The sponsors, developers, and users should be able to maintain a constant pace indefinitely.
The amount of work not done Simplicity—the art of maximizing the amount of work not done—is essential. -2000 Lines Of Code simplicity
Build projects around motivated individuals Build projects around motivated individuals. Give them the environment and support they need, and trust them to get the job done. On ValueOn Talent
Deliver working software frequently Deliver working software frequently, from a couple of weeks to a couple of months, with a preference to the shorter timescale.
Business people and developers Business people and developers must work together daily throughout the project. collaboration
Face-to-face conversations The most efficient and effective method of conveying information to and within a development team is face-to-face conversation. teamwork
Reflect, tune, adjust At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behavior accordingly.