Tag Archives: engineering

How to

“If you convert [your car] to run on copies of this book instead of gas, it will burn through 30,000 words per minute, several dozen times faster than the word consumption of a typical human.”

If you thought that “How to“, the follow-up to “What if…” would be more practical, then you’d be wrong.

Whether it’s chasing a tornado without getting up from your couch or moving your house with jet engines, Munroe takes another fun, inventive journey through science and maths. While it doesn’t quite hang together as well as “What if,” it still manages to amuse, educate1 and entertain.

There are so many good bits that it’s difficult to mention even a few highlights, but I think possibly my favourite part is where he fails to faze Colonel Chris Hadfield, even when asked how to land a space shuttle that’s attached to the carrier aircraft (response: “Easy peasy”).

If you’re at all interested in science or engineering, you should read this book (if you haven’t already). Just — please — don’t take the advice literally.


  1. I mean, not directly. You’re unlikely to have an exam where you need to know how to build a lava moat. But the thought-process in getting a serious answer to an absurd question absolutely has value. ↩︎

My delicious.com bookmarks for December 25th through January 9th

  • The Myth of Japan’s Failure – "Japan has succeeded in delivering an increasingly affluent lifestyle to its people despite the financial crash. In the fullness of time, it is likely that this era will be viewed as an outstanding success story."
  • Man Embraces Useless Machines, and Absurdity Ensues – Technology: making life simpler.
  • Merry – Sat here with my newborn son and wife, with all my family staying nearby, this post rang bells. It's sometimes important to realise what you have.

My delicious.com bookmarks for March 13th through March 14th

Communication

“Do you ever change this type of trade?”

I was sat on the trading floor discussing a new feature that I was implementing with the person who would be using it the most.

“No, never.”

This was one detail of the change that would have far-reaching consequences in the code. A “no” would mean a few days of development, a “yes” would indicate several weeks.

“Are you absolutely sure? You don’t change it even once a month?”

I knew they’d like the smaller estimate but, equally, I knew that I didn’t want to end up trying to implement several weeks worth of functionality in the smaller time frame. I’ve seen that kind of thing happen too often.

“John1, we don’t ever change these trades do we?”

John was the head trader. If anyone would know it would be him.

He rubs his head and leans back, thinking.

“Why would you want to? No, I can’t see us ever changing one.”

Of course, you can guess what happened thirty minutes into the first trading day with the new software.

So, what happened here? Why did we get the requirements so wrong? And why did we only find the mismatch after the system was moved into production?

Both the problem and the solution is the same thing: communication. Or more precisely, communicating using the right language.

Some developers are happy to only “speak” technical, proud that they are masters of their programming environment but ignorant of their users problems or how they really use the software.

Above I started out correctly, I was trying to understand the traders business and talking in terms of booking trades, positions, legal entities and a bunch of acronyms that would make even less sense out of context.

But I made one error: I used the word “change” without defining what I meant. I meant, well, any change. And so did they. Yet they didn’t consider moving a trade from one book to another to be a change and, unfortunately, I did.

You’d like to think that there were checks and balances in place to make sure that this kind of thing didn’t happen. And there were. In addition to informal and formal testing, there was over a week of “parallel running,” where the traders had to use the old and the new system together and check that the results were the same in both of them.

Were there any moved trades during this time? Of course. Why did the traders not notice? Well, it was about right; the differences, while present, were explicable and so not considered significant enough to mention even though I asked to hear about any problems at all.

So, again, communication. Or at least human nature. I wanted to hear about any differences but they tried to help me by only talking about differences that they couldn’t account for.

What’s the answer? Well, I’m not sure there’s an easy one. “Understanding your user” is a short, simple phrase but hides so much. If you spent the time to fully understood their job you probably wouldn’t have the time to do your own. But finding the balance is crucial.

  1. Names have been changed to protect the… well, they work for a bank so I hesitate to say “innocent” but you know what I mean. []

My delicious.com bookmarks for September 16th through September 29th

  • A Sense of Entitlement: Tweetie 2 – I think Apple needs to do more here — to allow for paid upgrades — but I also congratulate the author of Tweetie for having the nerve to charge for a significant update. He'll come across a lot of resistance but it's absolutely the right thing to do and it, potentially, paves the way for smaller developers to do the same thing.
  • Peep Show ‘won’t change’ for anyone – Looking forward to this. Slightly worried that it might overstay its welcome — how can you top eating a family pet in terms of gross out? — but then I thought that for the last couple of series too…
  • Fail Yet Succeed? – Nice discussion of the kind of things that all software projects go through. Really this is about half of my job!