Saturday, July 31, 2010

Eating your own dog food in the 1960s

It's common in the software industry to hear the phrase "Eat your own dog food". It's so common that Wikipedia has a page dedicated to the phrase. The idea is that a software developer should also be a user of the software they are developing. By analogy someone making dog food should make it good enough that they'll eat it themselves.

The phrase has been around since at least the 1980s, but I recently came across a much earlier expression of the same idea. And this came from one of the X-15 test pilots: Milton Thompson.

Some models of the X-15 contained a device that mixed the aircraft controls of the X-15 with the rocket controls. Since the X-15 would fly like a plane and a spacecraft it had both conventional airfoils and thrusters. These were originally controlled by different joysticks. The mixing device was the MH-96 and enabled the pilot to fly the X-15 in the atmosphere or in space using a single joystick.

But that meant that the MH-96 was controlling the X-15 with the input of the pilot. And so the pilot had to trust the MH-96 itself. Thompson wrote "As a pilot, you hope the guy who designed this electronic control system knew what he was doing. In fact, you would like him to be in the airplane with you to be exposed to any adverse results." Now, that's eating your own dog food.

More recently I had the pleasure of chatting with Sven Strohban who was the lead engineer on Stanley, the car that won the 2005 DARPA Grand Challenge.

He told me that he had a simple technique for ensuring high quality. When a software engineer told him that their module was ready for testing in the autonomous car, he would say: "OK, we'll load your code and you can sit in the car while it drives you around". Invariably, the engineer would need just a little bit more time before declaring his code ready.


Anonymous said...

That's remind me another situation

Programmer: what to do if ...

Boss: (lazy) that can never happens

Programmer: good, so I do not have to worry if that condition leaves to the total loss of data and to the explosion of all the computers around (and start World War III)

Boss: No !

Programmer: What the worry? That can never happens.

Captain Curt said...

The US military has long had a policy that anyone packing parachutes must be willing to jump with any parachute he packed (on pain of imprisonment) -- and this is periodically enforced.

About 30 years ago, IIRC correctly, this created a bit of a kerfuffle due to the expanding role of women in the military. If women were going to pack parachutes, they had to be trained to jump, and there was resistance in certain circles to this.