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Ask HN: Who's still keeping a DOS machine up because the business depends on it?

297 points · 304 comments · mlaux

  1. freeli · · focus · HN ↗
    A certain nuclear power plant had a Windows NT 4.0 machine running as late as 2007. The reason is interesting.

    The machine's purpose was to report status of the control rods that mitigate nuclear reactions. Basically, "are the rods inserted, and if so, how many / how far?". I want to emphasize that this was reporting only, NOT control.

    The original software was written back in the 80's, when the plant was originally commissioned, for AmigaOS. Of course, it's hard to buy Amigas anymore, and the original one died long ago (nobody remembers when).

    So in the mid '90s, the utility purchased an AmigaOS emulator that ran on Windows NT 4.0, which was current at the time. The emulator (IIRC) was developed by a firm in the UK. The firm went out of business sometime in the late '90s. The control rod monitoring software ran under this emulator on top of NT4.

    Windows NT 4.0 was the last OS to allow the emulation software direct access to the physical hardware that produced the status signal. Later versions of Windows abstracted the hardware access away, and the monitoring software broke. Because the emulation company had gone belly up, there was no way to fix the incompatibility.

    So the utility had a choice: get new hardware/software certified (by NRC?), or keep doing what they were doing with the software (and hardware) that they had. They chose the latter.

    So this is how, in 2007, during a tour of the facility, I stumbled across a Pentium 1 system running an AmigaOS emulator on Windows NT 4.0 that was responsible for displaying the status of the control rods of a nuclear power plant.

    Spare hardware for this setup was purchased off of eBay and stocked on an adjacent shelf.

    1. dahart · · focus · HN ↗
      > A certain nuclear power plant had a Windows NT 4.0 machine running as late as 2007.

      To put this in perspective, NT 4 was released in 1996, 11 years before 2007. That’s roughly the same as someone running Windows 10 today, which a lot of people still do. The Pentium 1 was only 14 years old at most. These parts of the system shouldn’t be surprising.

      The AmigaOS and software from the 80s are of course the older more interesting bits, but for critical infrastructure and safety, shouldn’t we expect and design for our hardware and software to last a long time, and not try to keep up with tech fads every decade? I feel like the main problem isn’t hardware or software that’s old, but that there wasn’t a longevity plan.

      It’s always been an interesting question how to write software that will last a hundred years. Maybe with AI this is the first time in history that planning to port & upgrade to new hardware every 5-10 years seems totally reasonable.

      1. driverdan · · focus · HN ↗
        > That’s roughly the same as someone running Windows 10 today

        While true the situation is different. Hardware and software moved a lot faster in the 90's and early 2000's. Everything has matured, is far more standardized, and moves more slowly now. Hardware from 11 years ago when Win10 was released isn't that different from today's hardware. Same goes for Win10 and Win11.

        1. dahart · · focus · HN ↗
          There might be a seed of truth there, but FWIW, I’m not very convinced by that. CPU speed development has slowed down a bit for sure, but software development is going faster than ever. GitHub and NPM and Python 3 and Rust all didn’t exist in 2007. CUDA was first released that year. LLMs weren’t being used. At the start of 2007, the latest Windows version was Windows 5, one more than Windows 4. Almost same as today. There isn’t a Windows 12 yet, while Windows 6 was released in 2007. So the pace of major Windows versions might be slightly slower. OTOH, the OS is much bigger than it used to be and it gets more frequent updates and point releases now than it did in 2007.
          1. throwawaysoxjje · · focus · HN ↗
            > At the start of 2007, the latest Windows version was Windows 5, one more than Windows 4

            Windows 2000 (NT 5.0) was released in 1999. Vista was NT 6, and released in 2006.

            1. dahart · · focus · HN ↗
              Where do you find 2006? My googling says NT 6 was released in early 2007, so I meant that on Jan 1 2007, Win 5 was still current. <a href="https:&#x2F;&#x2F;simple.wikipedia.org&#x2F;wiki&#x2F;Windows_NT_6.x" rel="nofollow">https:&#x2F;&#x2F;simple.wikipedia.org&#x2F;wiki&#x2F;Windows_NT_6.x

              It wouldn’t make a huge difference to me if 6 was released either 6 months earlier or 6 months later. In 2007, NT4 was only 1 major version behind for most people; adoption takes time. The broad timing of major versions being 4-5 years apart didn’t change until Windows 11, and we don’t know if that’s an outlier yet, but we do know that Microsoft has been changing the Windows release strategy, with more frequent updates. <a href="https:&#x2F;&#x2F;endoflife.date&#x2F;windows" rel="nofollow">https:&#x2F;&#x2F;endoflife.date&#x2F;windows

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