Brain Teaser

Years ago, when I was interviewing for Trilogy Software Group in Austin, Texas, I got my first brain teaser question.

You know, the question they ask that has no answer, or that has a really clever answer that you have to figure out.

It went like this: there are two room separated by a door which you cannot see through. You are in one room with three light switches. In the other room are three light bulbs. You cannot see anything at all about the other room from where you are. Each switch operates one light bulb in the other room. How do you figure out which switch operates which light bulb?

If you want to know the answer, drop me an email or a coment and I will post it. Suffice it to say I got the answer right, and got the contract. I really loved working with Trilogy, although there wasn't much lightbulb work to do. In fact, I never saw anyone on a lightbulb project the entire time I was there.

Years later I was interviewing for Captial One near Richmond, Virginia. They gave me a brain teaser as well -- I don't remember it exactly except for it was one of those problems with so many units that it drove me crazy trying to sort it out. The answer was probabaly something like "7", but I'll never know. This time around I did not get an offer, but I had a high billing rate so that could have been the cause. I'll never know, and quite frankly I could care less. Since then I've had several opportunities to consult with Cap One and turned them all down. Perhaps I was afraid of another question from hades.

I was thinking about these brain teasers this morning, when I found out that the devil himself had taken over my power outlet. You know, those little plastic strips we computer people plug all of stuff into. Turns out that on my little plastic strip, some of the outlets work and others do not. Or they all work, or they all do not. I think it changes every hour or so.

It took me about a week to figure this out. At first, I thought my notebook computers were loosing their AC adapters. Then I noticed that on some of the power plugs, the computers worked. Then, they stopped working. I was switching around wires, getting old power supplies out. I would get some configuration that worked, then I would start programming. BAM! A few hours later the power would go out. Broken computers would magically start working again. Sometimes I could switch the plugs and sometimes not. Sometimes I could go into another room and it would help. Sometimes not.

The worst kind of technical problem is an intermittant one. I still have bad dreams about code I've probably deployed with intermittant errors. But there's just not a lot to do about it. In programming, we can "instrument" our code (at a performance penalty) but we can't intstrument everything we use. Like my power supply. At some point in our efforts, we rely on other parts to work the way they are supposed to work. Work correctly. Or fail completely. But not a little of each.

So finally I figured it out. Whew! What a problem!

Lately my hosting provider is telling me that my SQL Server instance is going down from time to time. They can't figure out why, and my code has not changed. They've got a consultant from Microsoft (read: big bucks) helping out but he's stumped too.

I'm not sure, but I think they should check the power strip.