AgileAttitudes Article
 
 
 

Vol 02 Issue 07- House of Cards

  
 
Back to the list of articles Agile Attitudes Volume 2, Issue 07 June 28, 2005 A free bi-weekly email newsletter Brought to you by Agile Rules consulting www.agilerules.com ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Welcome to Agile Attitudes, a newsletter of ideas, insights and technical tips that help people find better ways to develop software. Feel free to share this with anyone - just be sure you send or print the whole thing, including the copyright notice. Directions for managing your subscription are below. O><O><O><O><O><O Agile Rules will be presenting a tutorial on TDD for Embedded Software development at the upcoming Agile 2005 Conference in Denver on July 26. We'll present a short version of this tutorial at the next Agile Bazaar meeting on July 14 at Tufts. Details to be announced on AgileBazaar email list. Agile related meetings and other events in the Boston area are discussed on the Agile Bazaar email list. For info see: http://groups.yahoo.com/group/AgileBazaar/ O><O><O><O><O><O If you would like to receive an email as soon as we know of an event in the Boston area of interest to the agile software community, you can sign up for the announcements list at http://www.agilerules.com/mailman/listinfo/agileannounce O><O><O><O><O><O A House of Cards by Ron Morsicato and Nancy Van Schooenderwoert Most of us have been trained on the job (and remarkably not in school) to develop a product in stages. There is a requirements analysis stage, followed by a design phase, and after reviews and many months of anticipation an actual coding phase. That's followed by a Validation and Verification phase, where oft times it's discovered that the software hadn't turned out to be everything it could be, at least to the eye of the user. We have been instilled with the philosophy to "Plan our walk, and walk our plan." In this newsletter we want to comment on the fallout of designing a system to a tee before actually observing it operate. The biggest problem is feedback. Designers do indeed crave it, but by having to wait for a system they instead turn to analysis and simulation. Both of these techniques, unfortunately, force the designer to make a set of assumptions, and humans, no matter how experienced and insightful, do err when making assumptions. Sometimes the error is benign or only a slight inconvenience, but sometimes, and perhaps too often, a system is based on an incorrect assumption that is a showstopper. Here's an example: Nancy worked on a large military vehicle system once where the sytems engineers had created a 4,000 page specification document, but the software people were just getting started on the first release. Later on in the project, management brought in a consultant to untangle the mess that the software had become. Nancy had a number of conversations with this consultant. The central question was: If everything had been so carefully planned, why all these problems? The spec listed what every software function would do, what parameters it would receive, and every other module it would talk to. Every detail had been thought out. That was precisely the problem! The tasking model of that CPU wouldn't allow the code to be written just as the systems engineers had envisioned. It had to be organized differently in order to take advantage of the processor's capabilities. Some of the software people understood that issue, but they only came into the picture after the spec was written. They were told to just code to the spec. This turned out to be a textbook example of why dialogue among groups, and incremental development are better than going too far on assumptions. One study of military projects tallied a success rate of a whopping 2%. So why is it that projects continue to do that "Big Design up Front?" Perhaps, as one frequent contributor to agile lists has suggested, it gives people the "illusion of control." After all, if the simulations work, it must be a design that works. But when it is found out that the system can't be built as designed, the reality sets in that you've got nothing but a fragile house of cards. The next newsletter issue will cover the Agile answer to this issue. O><O><O><O><O><O More articles on Agile software topics at http://www.agilerules.com Within our company we have a sub-specialty in embedded systems. Our site has articles on embedded XP and we support a discussion list focused on the use of agile methods for building embedded software. The list signup info is at http://www.agilerules.com/mailinglists.phtml O><O><O><O><O><O To help you get started with in-depth research into Agile Attitudes topics, we have added a Library section to our web site at http://www.agilerules.com/library.phtml Order using our links and receive discounts up to 30%! O><O><O><O><O><O If you enjoyed this issue or found it useful, forward it to a friend! Help spread the word about better ways to build software. Invite your friends and colleagues to join our growing reader community at http://www.agilerules.com/mailinglists.phtml O><O><O><O><O><O Looking for a speaker for your next corporate or society meeting? We present dynamic, informative programs on topics of interest to managers and technical staff in their transition to more flexible, robust ways to create software. O><O><O><O><O><O Want to reprint this issue in your company or society newsletter? For permission to reprint any of the articles, contact us at info@agilerules.com. O><O><O><O><O><O Your feedback is welcome! Send feedback to info@agilerules.com To manage your subscription: http://www.agilerules.com/mailman/listinfo/agileattitudes O><O><O><O><O><O Brought to you by Agile Rules consulting 162 Marrett Road, Lexington MA 02421 Copyright (c) 2004, 2005 Agile Rules info@agilerules.com O><O><O><O><O><O Privacy notice: We will not release a subscriber's address to any third party for any reason. This is a strictly opt-in newsletter. No one is ever subscribed without their explicit request. </plaintext> </td id="bodytable_r1_c3_body"> </tr id="bodytable_r1"> </table id="bodytable">