C. Keith Ray

C. Keith Ray writes about and develops software in multiple platforms and languages, including iOS® and Macintosh®.
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Tuesday, November 26, 2013

Quotes and Evolutionary Design Practices of Industrial XP


(Originally posted 2003.Apr.27 Sun; links may have expired.)

David Schmaltz said on the IXP mailing list: "Change never rests on the permission of the willing, but in the hearts of the brave and foolhardy." Let's hope we have supporting practices to not be too foolhardy. On the XP mailing list, Joshua wrote: "...most people react to change as if they are losing something. It's wired in to our human nature. I introduce XP into environments all the time. People think they're gonna lose something rather than gaining something with XP. I help them learn that they will be gaining a great deal."

On the IXP mailing list, Russ Rufer has provided the list of practices of IXP's Evolutionary Design:

  • Rapid Return on Investment
  • Risk Reduction
  • Backtracking
  • Selective Automation
  • Team Intelligence
  • Walkthrough
  • Spanning System
  • Small Iterations
  • Multiplicity & Selection
  • Dead Reckoning


  • I snipped quotations from this report

    http://www.sdmagazine.com/documents/s=7928/sdmsdw3d/sdmsdw3d.html, onto the IXP mailinsg list, and no one contradicted me, so here are some stabs at defining what some of the practices may be:
    Rapid Return on Investment - Developing only what needs to be done at the moment, leaving the rest to be filled in later, allowing early releases that can prove themselves quickly.

    Risk Reduction - Striving for design simplicity is a factor for reducing risk.

    Backtracking - Stepping back to find a simpler solution to a problem. "Backtracking not only helps you to consider other alternatives, it allows you to rewrite, aggressively refactor and prune any dead code."

    Selective Automation - "Quantity bows to quality: It's not about writing tests; it's about writing good tests"

    Team Intelligence - "Developers should devote maximum attention to improving the code."

    Walkthrough - "Studying, living and breathing code is at the heart of evolutionary design"

    Spanning System - "Evolving the code from a rudimentary system that, though primitive, provides end-to-end functionality. This simple working application is a thin, vertical slice of the project that offers insight into both essential and unnecessary features. Illustrated with a simple blackjack problem. To span the system, they chose just one case with two known hands and incrementally built the system to accommodate the full deck. "

    Small Iterations - "To implement a hotel reservation system, you might first implement a program that reserves just one room before developing the whole system. These small iterations can be viewed as embryonic versions of the system, and can be taken to the customer for feedback...this is the antithesis of RAD—instead of throwing your code away, you evolve it."

    Multiplicity & Selection - "Consider a multiplicity of design and selection, like the photographer who takes 10 rolls of film to find the perfect shot. Survival of the fittest."

    Dead Reckoning - "Navigating without explicit instructions, by heading in roughly the right direction, and using feedback to make adjustments and to motivate backtracking."


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