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RE: [XP] The Cost of Change Curve - XP vs other factors

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  • Steven Gordon
    Brad, I agree with your points, but they cannot create a truly flat cost of change curve. As Paul points out, your points and UB s points support the
    Message 1 of 115 , Apr 1, 2004
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      Brad,

      I agree with your points, but they cannot create a truly flat cost of change curve. As Paul points out, your points and UB's points support the conclusion the curve is still exponential but:
      - the technology improvements have made the factor that is being exponentiated significantly smaller than it used to be.
      - short iterations with sufficient feedback reduce the period of time over which the exponentiation occurs.

      This makes the exponential cost of change curve nearly flat in practice under XP with sufficient feedback and quality, and XP does indeed take advantage of this.

      Steven Gordon



      -----Original Message-----
      From: Brad Appleton [mailto:brad@...]
      Sent: Thu 4/1/2004 8:48 AM
      To: extremeprogramming@yahoogroups.com
      Cc:
      Subject: Re: [XP] The Cost of Change Curve - XP vs other factors



      On Thu, Apr 01, 2004 at 01:01:30PM -0000, Jeff Grigg wrote:
      > --- "Robert C. Martin" <UncleBob@o...> wrote:
      > > Some folks have said that XP flattens the curve. I don't
      > > think that's true. I think that whatever flattening has
      > > taken place has been because of things that are outside
      > > of XP's control. I think XP works *because* of this
      > > flattening; I don't think XP causes the flattening.
      > >
      > > What agency might have caused the flattening? [Computers
      > > are 1000 times faster, smaller, & bigger (storage)]
      >
      > Bob, you've been drinking too much of your own lemonade. Having a
      > bigger hammer only solves part of the problem.
      [...]
      > The powerful tools are nice, but their productivity benefits are more
      > than consumed by the increase in complexity and size of today's
      > applications.

      I interpreted Bob's post to be talking about something
      slightly different. I perceived the focus to be not so much
      on how "powerful" the tools are in terms of capabilities,
      but in terms of how the technology advancements have allowed
      us to reduce critical feedback cycle-times by twelve orders
      of magnitude. Today, I have nice GUI environments with lots
      of storage and processing power that can give me rapid
      feedback and interaction for a simple 2-3 line modification
      to edit-compile-link-load-test-examine.

      I think Bob was saying that XP was not responsible for the
      technology that made it possible to do all that in a matter
      of seconds rather than a matter of hours or days. XP was
      predicated on top of that kind of technology (e.g. Smalltalk
      rapid prototyping environment). And being able to do that
      in seconds rather than hours or days completely changes the
      approach I should take. If it takes seconds, the XP approach
      makes a lot of sense. If it takes many hours or even a few days,
      it makes sense to spend more "up front" time to make sure I
      get it right and do as much as possible during the time I would
      otherwise be waiting to schedule a slot of time to run my stack
      of cards thru the machine, and then wait till my turn came up.

      I heard Bob saying XP is responsible for leveraging that
      technology to best effect, and take advantage of the rapid
      feedback to adjust and correct and adapt in real-time rather
      than make guesses about a lot of stuff in advance that has
      a high likelihood of changing by the time you are able to
      run+test it.

      and more to be lost

      --
      Brad Appleton <brad@...> www.bradapp.net
      Software CM Patterns (www.scmpatterns.com)
      Effective Teamwork, Practical Integration
      "And miles to go before I sleep." -- Robert Frost




      [Non-text portions of this message have been removed]
    • Ron Jeffries
      ... No clue what you re referring to. I can search if you can give me more context ... Ron Jeffries www.XProgramming.com Those who attain to any excellence
      Message 115 of 115 , Apr 8, 2004
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        On Wednesday, April 7, 2004, at 9:55:42 PM, Kay Pentecost wrote:

        > I haven't gotten a really good answer yet... Except for some qualities that
        > Ron Jeffries listed a while ago... which provide a good starting point.
        > Maybe Ron would list them again. I have them printed out on several pieces
        > of paper so I come across them when I'm looking for something else... but I
        > don't know where they are now.

        No clue what you're referring to. I can search if you can give me more
        context ...

        Ron Jeffries
        www.XProgramming.com
        Those who attain to any excellence commonly spend life in some single
        pursuit, for excellence is not often gained upon easier terms.
        -- Samuel Johnson
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