One of the most useful features of Emacs is its interactive completion. Whenever you need to input the name of some item, Emacs allows you to type some parts of the name and then type TAB to see a list of items that match what you have typed so far. But completion is more sophisticated than just prefix-matching. You can use wildcards (for example * ( Read more... )

Toyota’s ‘Five Whys’ process is well known to engineers: it’s one of the basic problem-solving tools in modern engineering management systems like Six Sigma and Total Quality Management. Here’s how Taiichi Ohno introduces the process in Toyota Production System: Beyond Large-Scale Production (1978):
When confronted with a problem, have you ever ( Read more... )

I have been working on a project recently where there has been a lot of tricky debugging to do. The code I’m working on has to live in the same process as third-party code that is not under my control, and which calls into my code unpredictably, often from multiple threads or signal handlers. This is an application environment that’s particularly ( Read more... )

Since 2005, when a train crashes in the UK, a professional body of investigators-the Rail Accident Investigation Branch-is tasked with determining the cause of the incident and making recommendations to reduce the likelihood, or mitigate the severity, of similar events occurring in the future. There are similar branches tasked with investigating ( Read more... )

Martin Malins has been organizing the “Double Dutch” 200 km audax for four years now. I rode the first edition back in 2011, when we had the most amazing luck with the weather, and I was looking forward to riding it again. The route is a tour of the Fens: starting at Huntingdon, you head north-east via Ramsey, March, and Nordelph, then north up the ( Read more... )

Since the Heartbleed bug rendered all our passwords insecure, we’ve all been going through the purgatory of upgrading servers and changing passwords. This isn’t the first time I’ve done a mass-reset of my passwords, but I thought I’d try something new. ( This time I’m seeing what it’s like to try to follow “best practices.” )

It’s not easy designing a “DIY” audax route. The way these rides work is that you nominate a series of controls, then you ride around and visit each one in turn, collecting “proof of presence” in the form of receipts or cashpoint slips. The tricky bit is that you only get credit for the shortest distance between each pair of controls. So you pick ( Read more... )

Today was the "End of Hibernation", a 200 km audax organized by Terry Dickinson of Cambridge Cycling Club. Starting at the village hall in Hauxton, it visited controls at Adam’s Café near Stradishall, the Riverside Lakes Café at Onehouse near Stowmarket, and Bosworth’s Café at Finchingfield (plus two information controls).

( Today was the third ( Read more... )

The “Emitremmus” is a 100 km audax, run by Stevenage CTC each autumn for the last 19 years, on the Sunday that the clocks go back. The route starts at Fairlands Valley Park in Stevenage and heads east via Great Munden and Hare Street to Saffron Walden, returning via Great Chishill and Therfield. ( The start of the ride is almost exactly 50 km from ( Read more... )

The story so far:

1. 
   I introduced the tabular method by showing how to count the triangulations of a convex polygon;
2. 
   I used the tabular method to count the number of ways to triangulate an oriented n×n square using only lines joining the 4n integer points around the edge of the square and so solve Project Euler problem 270;
3. 
   I used the svgwrite ( Read more... )