Sunday, December 27, 2015

Keep your product in ship shape

Originally ship shape meant to adhere to the standards of tidyness and alertness necessary on seagoing vessels of the old times, where things tended to get turbulent from time to time.

Nowadays, with paradigms like ship it or the famous potentially shipable product increment another meaning emerges, at least in my perception.

Don't strip the headlights to get the tail lights working

When I was much younger than today I used to repair my cars myself. Partially out of interest, partially out of distrust towards the garages and partially because of financial restrictions. And of course, because in those days it was still possible to work on ones own car.

One of the things we used to do when some part didn't work was to exchange it with something that did. (duh!)

For example one time when the headlights where not working me and a friend tried a variety of things – after exchanging the bulbs and some tweaking with the wires we finally concentrated on the fuse which looked fine. But to make sure, we exchanged it with a fuse we knew to be in working order – the one that was wired into the headlight circuit.

And sure enough the taillight lit up. So we changed everything else back to the original state – bulbs and wires and all. Or so we thought.

The one thing we did not change back was the fuse. Silly – we simply forgot.

Happy to have working taillights again (the bug was fixed) I drove home. Almost. At least as far as the next police station, where a friendly officer motioned me to stop and explained that I could not drive with a car with only one headlight.

Today I see this happening with software all the time – people fixing just the problem at hand, without realizing what havoc they bring upon the rest of the system.

So please – whenever you “fix” a piece of software: Make sure that you can still ship the whole system.

My car was definitely not shippable at that time – make your software-craftsmanship better than the car-mechanic handywork of an untrained teenaged boy and keep your product in shipshape. In a state where it can be shipped to the real customer all the time.

till next time
  Michael Mahlberg

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