32 votes

GPS uses ten bits to store the week. That means it runs out... oh heck – April 6, 2019

15 comments

  1. [4]
    acdw
    Link
    Is there any reason to use these small numbers to store time information other than saving space? It just seems like integer overflow is a problem that keeps happening in time-sensitive software...

    Is there any reason to use these small numbers to store time information other than saving space? It just seems like integer overflow is a problem that keeps happening in time-sensitive software (see Y2K, 2038 problem, and now this), which after the first one you'd think these systems would be designed differently.

    9 votes
    1. [3]
      Maven
      Link Parent
      I think these systems were all designed a long time ago when storage space was still an important metric. Modern systems are probably (hopefully?) designed to, well, modern standards.

      I think these systems were all designed a long time ago when storage space was still an important metric. Modern systems are probably (hopefully?) designed to, well, modern standards.

      14 votes
      1. [2]
        JCPhoenix
        Link Parent
        Consumer-level GPS became widespread around early 2000s, right? We had cell phones, early versions of the iPod (though MP3 players were already available), USB drives, etc. Surprising that storage...

        Consumer-level GPS became widespread around early 2000s, right? We had cell phones, early versions of the iPod (though MP3 players were already available), USB drives, etc. Surprising that storage was still considered "scarce."

        3 votes
        1. stingraycharles
          Link Parent
          GPS was already deployed long before then, it's just that the US military authorized access to civilian applications during the 90s. First GPS satellite was deployed in 1974, civilian use started...

          GPS was already deployed long before then, it's just that the US military authorized access to civilian applications during the 90s.

          First GPS satellite was deployed in 1974, civilian use started in 1985: https://www.pcworld.com/article/2000276/a-brief-history-of-gps.html

          16 votes
  2. [2]
    Algernon_Asimov
    Link
    It's Y2K all over again! Well, we got through that without too many hassles (thanks to a lot of work by coders around the world). I assume we'll get through this as well.

    It's Y2K all over again!

    Well, we got through that without too many hassles (thanks to a lot of work by coders around the world). I assume we'll get through this as well.

    6 votes
    1. Amarok
      Link Parent
      Part of me is wondering... is this a real problem, or just an excuse for the media to enjoy another baby Y2K hype cycle. Fear sells, after all. I still have my Y2K coffee mug. :P

      Part of me is wondering... is this a real problem, or just an excuse for the media to enjoy another baby Y2K hype cycle. Fear sells, after all.

      I still have my Y2K coffee mug. :P

      1 vote
  3. unknown user
    Link
    Hmm. I think the real issue here will be devices not properly following the specification that they should (mentioned in the article). I think many devices will fail due to manufacturer laziness....

    Hmm.

    I think the real issue here will be devices not properly following the specification that they should (mentioned in the article). I think many devices will fail due to manufacturer laziness. And as for software updates, only the most recent devices are likely to get any (let alone actually be updated by the end user). And those most recent devices are probably already patched anyway.

    I think the real issue will be embedded GPS devices such as the ones sometimes built into some cars that don't get updated.

    But with so many people using phones for navigation anyway, I'm not sure that this will actually matter too much.

    As someone else mentioned in this thread, it's like a mini Y2K

    4 votes
  4. [2]
    mrbig
    Link
    Someone wrote not long ago (maybe here on Tildes? can't remember) that most embedded devices will need to be replaced much before all those "tech armageddons" anyway. I don't know if that's true,...

    Someone wrote not long ago (maybe here on Tildes? can't remember) that most embedded devices will need to be replaced much before all those "tech armageddons" anyway. I don't know if that's true, but it makes sense. These things break all the time.

    2 votes
    1. Archimedes
      Link Parent
      Well, this one is less than 2 months away.

      Well, this one is less than 2 months away.

      5 votes
  5. [3]
    Octofox
    Link
    Why does this break devices? Why can't they keep working without knowing the correct date? I'm guessing they have to do some kind of calculation with the date to know where the gps satellites will be.

    Why does this break devices? Why can't they keep working without knowing the correct date? I'm guessing they have to do some kind of calculation with the date to know where the gps satellites will be.

    1 vote
    1. [2]
      Ordinator
      Link Parent
      I don't think it does, broadly speaking. I don't see anything more dire than the quote below in the article. As also noted in the article, this could break devices that expect their GPS source to...

      I don't think it does, broadly speaking. I don't see anything more dire than the quote below in the article.

      GPS devices with a poorly implemented GPS Time-to-UTC conversion algorithm may provide incorrect UTC following a week number rollover," US Homeland Security explained in its write-up (PDF) of the issue this week.

      As also noted in the article, this could break devices that expect their GPS source to provide an accurate date/time.

      1 vote
      1. Amarok
        Link Parent
        I think the issue is that with modern computing, we've trained all of the systems to flip out if the time is wrong when talking to their neighbors. If your system's time is more than five minutes...

        I think the issue is that with modern computing, we've trained all of the systems to flip out if the time is wrong when talking to their neighbors. If your system's time is more than five minutes off from your domain, for example, it'll refuse to log you into the domain. Little headaches like that from time mis-matches lie in wait everywhere in the IT world. If the GPS devices lose their time accuracy, it's fair to say that the devices talking to them will be the ones to freak out. Also, who knows what bugs lurk, untested-for, based on that mess in the code.

        2 votes
  6. [2]
    Comment deleted by author
    Link
    1. nsz
      Link Parent
      I used one like this in uni, might get one of those serial read usb sticks just to test the unit I've got when the time comes. But my guess is manufacturers saw this coming and put something in...

      I used one like this in uni, might get one of those serial read usb sticks just to test the unit I've got when the time comes. But my guess is manufacturers saw this coming and put something in place to handle it. The article says as much;

      (...) devices on sale right now should be prepared for this rollover and handle it gracefully. (...) built after, say, 2010 should be fine, provided they follow the specs and notice the rollover.

      3 votes
  7. [3]
    Comment deleted by author
    Link
    1. Deimos
      Link Parent
      Whoops sorry, I edited it to add the date to the title because I thought it was important, and then managed to add the wrong date.

      Whoops sorry, I edited it to add the date to the title because I thought it was important, and then managed to add the wrong date.

      4 votes