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Re: Teaching/developing troubleshooting skills
DG> Date: Fri, 25 Jun 2004 20:04:38 -0700 DG> From: Darrell Greenwood [ editted for brevity ] DG> The 5 day course can be boiled down really to one concept DG> that can be taught in 5 minutes... "binary search". Every half-decent programmer knows O(log(N)) is one's friend unless the scalar coefficient is large. A good way to demonstrate its efficiency is: * Have someone pick an integer between 1 and n, inclusive * Make guesses, going "higher" or "lower" according to the number-holder's feedback. The uninformed are surprised that one can always guess the number from 1 to 1000 in ten iterations or less. DG> The reason I am writing this note is as I went through a DG> career of troubleshooting I was surprised at the number of DG> colleagues who had no concept of "half-splitting" and used DG> "linear" or "random" techniques to determine test DG> points/tests with a corresponding dramatic reduction in DG> effectiveness. Good point. [ below text in response to nobody in particular ] It's also important that one avoid: * The faulty assumption there is but one problem * Incorrectly-formed causal relationships (NANOG-L has some examples of these) * Making too many changes in one iteration * Attempting to tackle a system with more unknowns than are absolutely necessary. A certain amount of troubleshooting can be taught, but IMHO it requires a self-driven person with intuitive reasoning. Finally: Apprenticeship. Have the novices follow along when experts work actual cases. A certain amount of troubleshooting is developing the intuition to make informed guesses -- e.g., "some idiot broke pmtud" -- and develop good leads without having to search methodically through the entire problem space. Eddy -- EverQuick Internet - http://www.everquick.net/ A division of Brotsman & Dreger, Inc. - http://www.brotsman.com/ Bandwidth, consulting, e-commerce, hosting, and network building Phone: +1 785 865 5885 Lawrence and [inter]national Phone: +1 316 794 8922 Wichita _________________________________________________________________ DO NOT send mail to the following addresses: email@example.com -*- firstname.lastname@example.org -*- email@example.com Sending mail to spambait addresses is a great way to get blocked.