Software engineering and alarm clocks

This morning at church a woman said she was running late because of a software issue. Her alarm clock was manufactured before the US changed the end date of daylight saving time. Her clock “fell back” an hour because daylight saving time would have ended today had the law not changed.

Here are a few thoughts about what went wrong and how it might have been prevented.

  • Laws have unforeseen consequences. When the change was being debated, I doubt many asked about the impact on alarm clocks and other devices with embedded software.
  • The clock tried to be helpful by automating the time change. It would have been better had it done nothing. Moderately smart software is often worse than no software.
  • Should the clock have been designed to check for software updates? What would it have done to the cost to turn a simple clock into a computer with a network connection?
  • The clock could depend on a radio signal for time. Some do, and they’re very accurate. But they’re also more expensive.
  • Should we get rid of daylight saving time? It made more sense when nearly everyone had a 9:00 to 5:00 work schedule. But now that so different people work shifts or have flexible schedules, it doesn’t seem to add as much value.

Related post: Universal time

8 thoughts on “Software engineering and alarm clocks

  1. “Radio controlled” clocks may be precise, but not always accurate. I have an “Atomic Watch” which is always wrong for the first day of the switch to/from DST, because it polls the NBS once a day, at _midnight_.

    As for “Should we get rid of DST?” Yes, of course, but we won’t because the nightlife industry makes more money with it, and doesn’t care that you drive to work in the dark, as long as you spend more money at the pub. And they have more political clout than anybody with a 9-5 job.

  2. John,

    Very good point about moderately intelligent software being worse than none at all. Also ties in with the concept of the “law of unintended consequences”!

    Just recently I’ve read a couple other blog posts on the same topic – the sense (or senselessness) of daylight savings time & semi-annual clock changes:

    Colin Walls, who writes quite a bit on embedded software topics, has penned a couple blog entries in the last few months on the topic.

    The most recent one, Becoming a millionaire, takes a stab at quantifying the lost productivity due to the clock changes… to quote:

    What about all the effort involved in making the change twice a year? How much time is wasted? Around the world, there might be, say, a billion people adjusting their clocks. Maybe it takes them 5 minutes twice a year. That adds up to 10 billion minutes – 167 million hours. There is a lot that could usefully be achieved, given that number of man-hours.

    Kinda makes you think! Of course, then again, if we were to add up all the time we waste stuck in traffic, waiting at grocery checkouts, etc. we’d all just give up :-)

  3. John,

    As a computer scientist, you hit the head on the nail with this: “Moderately smart software is often worse than no software.” It ties nicely with your simile of software as an exoskeleton as opposed to a robot.

    As a statistician, you already know the best response to your last question (“Should we get rid of daylight saving time? It made more sense when nearly everyone had a 9:00 to 5:00 work schedule. But now that so different people work shifts or have flexible schedules, it doesn’t seem to add as much value.”): look it up.

    Thanks for yet another thoughtful post.

  4. Let’s please get rid of DST. We lived in Indiana for several years, where — until recently — DST was not observed. The governor pushed through DST legislation because it supposedly would make Indiana more competitive in the business world since we’d be on the same time schedule as everyone else. I suppose there’s something to that, but all I know is that Indiana’s legislature probably never had to put a 3-year old to bed while the sun was shining on her face through her window. Having the sun up until almost 10 PM is just abominable. So let’s ALL get rid of it.

    This sort of reminds me of a discussion thread on Slashdot not too long ago about getting rid of time zones, period.

  5. For computational purposes, we have largely gotten rid of time zones and DST. Nearly everything that has a time stamp uses UTC internally. Displaying that time to humans, however, has to deal with time zones etc.

    I think time zones are a necessity for human purposes: we expect the sun to be overhead at approximately noon. China should naturally have several time zones but doesn’t. I suppose people adjust their schedules to live by solar time rather than official time, e.g. waking up somewhere around sunrise etc.

  6. I thing the time change is outdated. We should switch to daylight saving time and never switch back. The cost of having to cope with the change (and the changing legislation around the change) is likely greater than the energy savings, which as I understand it were the initial motivation for the change.

    Also, I have a radio-synchronized clock in my living room. Apparently the designers decided not to bother with DST, since there’s a switch on the back which toggles whether we’re on DST or not. It solves the problem Mike raises about the clock being wrong until it manages to sync, and solves the original problem of timekeeping devices which think they’re smarter than they are, but does not solve the problem of forgetting to set the clock at all.

    (Back when I had an intellectually-challenged feature phone, I did some tests with the alarm clock. If I set an alarm for 8am on Saturday night before DST ended and then the time changed early Sunday morning, the alarm would ring at 9am. To paraphrase Charles Babbage, I cannot rightly apprehend the confusion of ideas that could provoke such an implementation.

  7. I wonder how many people, like myself, threw out their annoying old alarm clocks that were switching time automatically to the old DST schedule? DST is bad enough to deal with but I didn’t want to have to manually remember the old system and the new switching my clock 4 times a year. Seems like this could have generated significant waste.

  8. Tim: This week I threw out the alarm clock I’ve had since high school. It didn’t automatically change time — clocks didn’t back in the dark ages — but now I can’t reset the time manually either because the button to do so wore out. It was fine until the time changed.

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