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

Do you currently work with or know anyone who is still using:

* dBase/Clipper/CLARION/Paradox/other DOS RAD environments on period hardware to run business processes?

* CNC mills/spectrometers/microscopes/other industrial instruments controlled by ISA cards (either bespoke or standards like GPIB)?

* Anything with a parallel port dongle?

If so, I'd be very interested in hearing your experience here, or feel free to send me an email at the address in my profile. I'm not trying to sell anything, just doing some research for an idea around keeping these going on modern hardware.

210 points | by mlaux 21 hours ago

71 comments

  • freeli 18 hours ago
    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.

    • justin66 4 hours ago
      To me the funny part of this story is that they used to show you this warning as part of the EULA when installing Windows NT 4, which I remember joking about:

      NOTE ON JAVA SUPPORT. THE PRODUCT MAY CONTAIN SUPPORT FOR PROGRAMS WRITTEN IN JAVA. JAVA TECHNOLOGY IS NOT FAULT TOLERANT AND IS NOT DESIGNED, MANUFACTURED, OR INTENDED FOR USE OR RESALE AS ONLINE CONTROL EQUIPMENT IN HAZARDOUS ENVIRONMENTS REQUIRING FAIL-SAFE PERFORMANCE, SUCH AS IN THE OPERATION OF NUCLEAR FACILITIES, AIRCRAFT NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL, DIRECT LIFE SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH THE FAILURE OF JAVA TECHNOLOGY COULD LEAD DIRECTLY TO DEATH, PERSONAL INJURY, OR SEVERE PHYSICAL OR ENVIRONMENTAL DAMAGE. Sun Microsystems, Inc. has contractually obligated Microsoft to make this disclaimer.

      Also:

      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.

      It would take a whole lot more context to make this somehow comforting. :D

    • throwaway2037 6 hours ago
      This is a great post. How does someone write software that needs to run for ~50 years where the hardware will need to be replaced with non-equivalent, newer hardware? If I were facing this issue today, I might start with an OS that has excellent emulation. Example: Can I run 32-bit MS Windows 95 via emulation on a variety of current 64-bit OSes, like MS Windows, Linux, AIX, HP-UX, etc. If yes, then we can assume(?) this emulation will remain relatively stable even if we upgrade our hardware later. Maybe I am overthinking the whole problem: Can VMs do exactly what I want today? Will VMs running ancient OSes, such as 32-bit MS Windows 95, continue to be stable/viable in the future? I am unsure.
      • ninalanyon 4 hours ago
        Make sure that you have as thorough a specification of what the system is supposed to do as you can.

        Then define the version control system and the build process, specifying the dependencies, and so on.

        Think about any opaque blobs in the system and try to eliminate them so that you have plain text source code so that no tools are needed to read the code.

        Make sure that the build process runs entirely locally and never fetches anything from outside.

        Simplify everything, use only tools and languages that are well understood and supported.

        The real problems are not strictly technical but social: how do you prevent loss of the code, the tools, the specification, how do you maintain the expertise needed to maintain it. How do you ensure that all those things that are obvious to you now are written down in all their gory detail so that your great grandchildren will not apply their new and different preconceived ideas to the system?

        Document all this on paper as well as electronic storage, make sure that version ids are recorded on every page as well as being available to the user of the machine or program.

        In the industry in which I worked for the last thirty years of my career it was not uncommon to have things come back for repair after fifty years use and to be able to consult the original drawings and bill of materials so that exact replacement parts could be made.

      • steveBK123 11 minutes ago
        > How does someone write software that needs to run for ~50 years

        You in a lot of ways have to respect the ability to have done this in the first place, compared to todays slopware which manages to break within 1-2 mandatory OS update cycles.

      • jl6 5 hours ago
        > How does someone write software that needs to run for ~50 years where the hardware will need to be replaced with non-equivalent, newer hardware?

        Some ideas:

        Write it in a popular language/ecosystem, stick rigidly to well-defined APIs, use commodity hardware, flatten out any malignant cleverness, maintain documentation on why every part does the thing it does, and make the source code readily available.

        This is based on working with some very old systems, and each point above is the opposite of something that made life harder.

        • inopinatus 2 hours ago
          Unfortunately, “popular language/ecosystem” includes JavaScript and PHP.

          I’d go for “universal and timeless”, which has meant C for several decades now. There is, I’d concede, a reasonable chance that Rust obtains that label in our lifetimes.

        • brudgers 1 hour ago
          The Amiga was a popular ecosystem.
          • jl6 36 minutes ago
            And as a result it's very well emulated, making it very likely that Amiga code can still be run in 50 years' time.
      • brudgers 1 hour ago
        run for ~50 years where the hardware will need to be replaced

        If it needs to run for fifty years, specify hardware that has a long support cycle such as Mil-Spec.

        That’s why the Z80 was around for so long and why so many companies in the 80’s and 90’s still deigned around it. (1)

        If you let programmers drive system design, winding up with an “Amiga” in your certified design is a more probable outcome…

        (1) there’s a moderate chance that new hardware that can run Z80 code will be around fifty years from now.

      • dmos62 6 hours ago
        > how does someone write software that needs to run for ~50 years where the hardware will need to be replaced with non-equivalent, newer hardware?

        Make it open-source, or don't buy without source.

        • booty 1 hour ago
          It's interesting to think about this in the context of parent poster's story about the Amiga emulator in the nuclear power plant.

          Or, more broadly, in the context of any situation where the software is closely coupled to a specific operating system and/or hardware.

          Having the source code would have helped tremendously, but might not have been sufficient because of the hardware story and the regulatory approval factor.

        • jmalicki 1 hour ago
          You don't need source anymore. Have Claude Code look at the binary and write a new program.
          • esafak 1 hour ago
            I wouldn't rely on that for mission critical systems.
      • cozzyd 2 hours ago
        Write it in C or Fortran.
      • ndsipa_pomu 4 hours ago
        I'd recommend not having it so dependent on the hardware and choose an OS that is relatively hardware agnostic (e.g. Linux). Also, ensure that the software is open source and if compiled, has an open source toolchain to do so.

        Though people often decry it (due to the many, many footguns), writing something in Shell/BASH will make it trivial to move to newer machines.

    • Froedlich 17 hours ago
      A friend works for an airline as a flight simulator tech. Their entire software stack, including the compiler and OS, is FAA-certified.

      Then their ancient Honeywell(?) mainframes reached end-of-life they scouted for compatible hardware, of which there was none. The cost of certifying new software, plus the time involved, was astronomical. So, after consulting with the FAA, they paid a hardware company to clone the ancient mainframes in modern silicon. The FAA signed off on it, and they had all-new computers - much smaller than the originals - running the old stack.

      • zx8080 16 hours ago
        It's _very_ hard to believe some company to simply "clone the mainframe" into chip. Mind sharing any link to this effort?
        • mitxela 6 hours ago
          Custom chips aren't as expensive as you think. About a few million dollars for the design and a hundred thousand chips, way out of reach for a hobbyist, but accessible to large enough companies. Just because it's opaque to us software people doesn't mean it's not a real industry you can buy things from.
          • realo 4 hours ago
            And all that expensive engineering is still less costly AND faster (!!) than a new software certification.

            Cannot refrain myself from asking why ...

            • ianjbutler 4 hours ago
              Situation: Software-1 on Platform-1, both certified.

              Time-evolution: P1 is deprecated, replaced by uncertified P2, but S1 remains certified.. just nowhere certified to run yet.

              Solution: There's another software S2 which originally vouched for P1, itself still certified, which can still be used to certify P2.

              Counterfactual?: If S1 were deprecated in favor of new S3.. there'd be no plan to certify it!

              The problem: None of this actually makes any sense! But we're trying to fake due diligence. Everyone knows the hardware/platforms kinda need to be certified with respect to each other anyway, but if we did it that way it would all be even more expensive an time-consuming.

            • mitxela 4 hours ago
              Doesn't seem crazy to me. Which one do you suppose needs more proof of correctness: a cake recipe, or the oven you bake the cake in? The recipe has to be correct or the cake won't work, but the oven just has to hold a temperature.
              • starky 58 minutes ago
                Ovens vary greatly. There is no consistency in how even the heat is in the space, the airflow through the space, how much and how fast the temperature varies around the set temperature, etc. These things all do affect how things bake up and often people have to tweak recipes for their specific oven.

                In a case where something is safety critical the computer is super important as very subtle errors could cause catastrophic consequences. This is why you get into things like running software on 3+ computers concurrently depending on how fail-safe something has to be.

              • realo 2 hours ago
                That "just" is quite the load-bearing seam ...

                Particularly when the task here is "just" to measure some rod positions in a constrained 3D space ...

        • flyinghamster 3 hours ago
          It could be an FPGA. Given enough gates, and the know-how to program them, you can make an FPGA emulate anything. Speed and efficiency could be better or worse, but if you're targeting old hardware, better is likely.
        • vincent-manis 15 hours ago
          When Xerox established PARC, they asked the assembled scientists what computer they wanted. The majority view was a DEC PDP-10 KA10, with the BBN memory management unit that let it run Tenex (the ancestor of DEC TOPS-20). Xerox couldn't really buy a competitor's mainframe, so they built MAXC (maximum access computer), which was a complete emulation of the Tenex machines.
          • zem 7 hours ago
            very apt that xerox parc was full of tenex engineers!
          • fsckboy 50 minutes ago
            >MAXC (maximum access computer), which was a complete emulation of the Tenex machines.

            Compuserve also had a software dependency on the PDP-10 and Decsystem 20, and when those machines were no longer available they bought a company making clones so they could continue to manufacture them for themselves. The company they bought, Microsolutions, was Mark Cuban's first startup.

            making clones of mainframes (IBM's) had been a big area of intellectual property litigation, but also facing monopolization investigations, IBM had to allow them. They were referred to as "plug compatibles".

        • znpy 7 hours ago
          Meh, old architectures are relatively simple and you can get 95% of those via fpga softcores (some freely available, some paid) and run them on fpga. The rest can be implemented by a proper ee team.
        • theodric 7 hours ago
          I mean...there's some precedent. The XKL TOAD ("Ten On A Desk") implements the PDP-10 instruction set, and will happily run TOPS-10/TOPS-20. LCM had one doing just that.

          https://www.computerhistory.org/collections/catalog/10277383... https://www.twenex.org/?network

      • fsckboy 1 hour ago
        >Then their ancient Honeywell(?) mainframes...

        https://en.wikipedia.org/wiki/GE-600_series from the 36-bit era which turned out to be a sweet-spot for Lisp; also "famous" for running Multics (old joke flipped: "which was many of whatever unix is one of")

        GE sold it's division to Honeywell, and from there to Group Bull (French) and then to NEC (Japan)

      • betaby 16 hours ago
        That's interesting. That means there are fewer checks for hardware than software?
        • hulitu 8 hours ago
          Software "engineers" like to abstract things. This doesn't pay well e with reliability.
        • soulofmischief 16 hours ago
          Hardware is more amenable to static analysis than running programs which may receive an arbitrary number of inputs and express an arbitrary number of possible intermediate states.

          I am interested in how firmware is treated, since perhaps in the case of these old machines it's small enough to be analyzable or at least cloned bit-for-bit.

    • CobaltFire 18 hours ago
      Having worked on nuclear plants (as a reactor operator) around that time this doesn't surprise me in the least.

      Thats far more advanced than the systems I worked with, one of which reported rod position via resistance measurement on a brushed cylinder (one for angular and one for depth).

      Cleaning and calibrating those was a constant maintenance item every time the reactor was shut down.

    • kccqzy 18 hours ago
      Did they not need NRC recertification when they moved from a physical machine running AmigaOS to an AmigaOS emulator?
      • freeli 18 hours ago
        That is an advanced question best asked of the folks in charge of the plant. At the time I was just trying to figure out how to explain to the IT auditors why there was no antivirus software on this piece of crap.
        • CursedSilicon 16 hours ago
          Could you skirt around it and just remark "there are no viruses for AmigaOS"

          (Probably not literally true. But functionally true in the sense that they were likely transmitted via infected floppy disks, of which there'd be virtually none left in the wild in 2007)

          • kamma4434 6 hours ago
            Hello, my name is Lamer Exterminator, pleased to make your acquaintance.

            https://en.wikipedia.org/wiki/Lamer_Exterminator

          • freeli 16 hours ago
            It wasn't the AmigaOS running in the emulator that they were worried about, it was the Windows system running the emulator. (Not that the average IT auditor there could have understood the difference.)
            • M95D 12 hours ago
              How would a virus get in there?
              • EvanAnderson 8 hours ago
                If it were a newer version of NT I'd be concerned about USB media, but being NT 4.0 and not supporting USB it's imminently more capable of being air-gapped than later versions. (I recall a fun Ed Skoudis quote-- "At best, an air gap is a high-latency connection". Evidence Stuxnet.)
              • jabl 8 hours ago
                The auditor probably doesn't know nor care. "Every windows machine runs antivirus" is a checkbox item, zero thought involved.
          • rcxdude 6 hours ago
            Depends. A lot of these audits are quite prescriptive and don't leave much room for actually thinking about the problem. There is often some kind of mechanism for 'this is sufficiently segregated it doesn't matter that it's utterly out of date' but then usually some awkward rules develop that prevent some things from being put into that category. More subtly you can get whether the thing even exists as a thing that the audit cares about, and that often depends on the framing (embedded software is often invisible here but it needs to not look too much like a general-purpose OS even though it often is).

            (Also, in my experience, what the auditors think the rules are and what is written down can often be divergent and even contradictory)

    • the__alchemist 4 hours ago
      It is wild to me that you would use any GPOS for something like this instead of dedicated firmware for the task. This is evoking similar reactions to when I read articles about infrastructure being hacked remotely: Something must have taken a wrong turn with the architecture design for this to happen!
    • rkagerer 3 hours ago
      Nothing wrong with this.

      If it ain't broke, don't 'fix' it.

      • mikeweiss 2 hours ago
        Just make sure that its well isolated from the Internet!!
    • vincent-manis 15 hours ago
      This reminds me of the apocryphal story of the IBM System/360 running a 1410 emulator that ran an IBM 705 simulator that ran a business-critical application.
      • JdeBP 11 hours ago
        Not wholly apocryphal. The U.K.'s air traffic control ran, and possibly still is running, on an IBM 4381 substituting for an IBM 9020.

        * https://news.ycombinator.com/item?id=49763972

        They've reportedly already tried, and failed, to replace it with a more modern system.

      • genxy 12 hours ago
        Which is why we should target VMs directly. Then that VM can be brought forward to new platforms rather than emulating the entire machine, not that emulating the entire machine is bad. One could argue that the emulation stack you outline was made possible by putting in the work to make simple, fully specified and documented hardware.
    • tombert 13 hours ago
      I find it deeply upsetting that anything important for a nuclear power plant is using an OS without protected memory.
      • wat10000 2 hours ago
        You don't need protected memory if your program is the only thing running. Plenty of microcontrollers have no protected memory and get used in safety critical applications.
      • M95D 12 hours ago
        Protected against what?
        • tombert 12 hours ago
          Just another program poking memory it’s not supposed to. Not even necessarily maliciously.
          • JdeBP 11 hours ago
            That AmigaDOS emulation will almost certainly never run another program. (-:

            Far more concerning from a RISKS point of view is the spare parts being physically in the same place as the live machine.

          • thesuperbigfrog 55 minutes ago
            > Just another program poking memory it’s not supposed to. Not even necessarily maliciously.

            What other program? Most DOS versions were not multi-tasking beyond "terminate-and-stay-resident" (TSR) programs like mouse drivers.

            Whatever application you ran on DOS was THE application your computer was running.

    • ikidd 17 hours ago
      NT4.0 in 2007? That wasn't even very late. I was replacing NT4 servers into the early 10s. Car dealerships were terrible for keeping that crap around.
    • gerdesj 18 hours ago
      "Windows NT 4.0 machine running as late as 2007"

      lol. I know a ... factory, that had a BBC model B (with a rather complicated wiring loom) still doing a job around that time.

      The IT supplier at the same factory went to a museum in Cambs. around late '90s, early '00s to ask if they could buy an exhibit because something had failed locally. The museum gave them the part.

      That was just aerospace and nothing fancy like your nuke plant!

    • dahart 2 hours ago
      > 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.

      • driverdan 2 hours ago
        > 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.

        • dahart 1 hour ago
          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.
          • throwawaysoxjje 59 minutes ago
            > 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.

            • dahart 14 minutes ago
              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. https://simple.wikipedia.org/wiki/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. https://endoflife.date/windows

    • collingreen 50 minutes ago
      That must have been a crazy moment for you when you first saw it and a big sigh moment for whomever had to explain it to you the first time. Thanks for sharing this; it made me smile!
    • slicktux 13 hours ago
      Was this status indicator simple vertical bars that were black and white and displayed on an old CRT Monitor? Almost looks like black and white terminal vertical bars (like Alsamixer)?
    • icedchai 18 hours ago
      I'm curious, how did the hardware present itself? It couldn't have been an Amiga Zorro card since it would've been impossible to get that into a PC. Did it connect over a serial or parallel port?
      • freeli 17 hours ago
        I recall it being some custom ISA card with connectors on the back. The emulation software had drivers that interfaced directly with the card.
        • icedchai 17 hours ago
          Interesting! So they were able to port the hardware but not the software for whatever reason?
          • ErroneousBosh 8 hours ago
            If it's what I suspect it might be, it was probably a generic IO card with maybe a bunch of 8255 PIOs on.
    • throwaway27448 2 hours ago
      How on earth are these massive pieces of infrastructure relying on software they don't have the code to? i'm just utterly confused how these things happen.
    • ptek 12 hours ago
      If it's still running I wonder what they are going to do about the year 2038.
      • mitxela 6 hours ago
        Set the date back to 1980 and sticky tape over the corner of the screen where the date is displayed.
    • DoctorDabadedoo 17 hours ago
      I wonder if there is push in the public sector for open source software/hardware for cases like this.

      I completely get the decisions over time here, but it's unsettling having a relevant piece of software (reports are important too!) working on with parts from ebay, in 50 years time they might be gone.

      • NegativeK 15 hours ago
        I've dreamt of governments hiring devs with promises of full time OSS work. It _might_ get some people over the lower salaries of government work. But I overheard a state CIO once say "We configure, we don't create".

        That's to say nothing about opinions of open source that rival early 2000s Microsoft.

        For old ass critical software and hardware, the org can always have a backlog of hardware and contingency plans (paying someone to fix the hardware, paying someone to create a fully certified and modern solution..) for when they start running out of parts.

    • sajithdilshan 8 hours ago
      This is crazy. Why on earth wouldn’t the respective government spend money to modernize a critical infrastructure like a nuclear power plant?

      This is how we would end up with nuclear disasters, not because the technology is bad, but purely because of mismanagement and human negligence.

      • onion2k 8 hours ago
        This is crazy. Why on earth wouldn’t the respective government spend money to modernize a critical infrastructure like a nuclear power plant?

        Safety and reliability come from understanding the system. Something that's old but that you know everything about is far safer than something new. This risk is that the people who know move on, or the sources of replacement parts stop working, or that other things around the system change. Then the risk curve inverts and you find the old system more of a liability than a asset.

        Almost always people choose to update things either too early or too late. Knowing when to do something is hard.

        • sajithdilshan 6 hours ago
          That’s pure negligence. It’s not like the people that have the know how disappear suddenly . It’s the responsibility of the management to make sure the knowledge transferred to new generation.

          I guess that kind of thinking is what led to the collapse of ancient civilisations like why even bother to improve anything and let everything decay and die out

          • somenameforme 5 hours ago
            You can only say such things with hindsight. In the moment, nobody knows what the future will hold. Take the space program in the US for instance. In 1969 we landed a man on the Moon. We'd repeat that several times until 1972. At that point Nixon made a speech which implied various unpleasant things about space's future, but he'd be out of office, disgraced, a couple of years later, so how big a deal could it have been anyhow?

            I think almost nobody from that era would have believed you if you told them that more than 50 years later not a single human would have traveled beyond low Earth orbit, and that we'd now be struggling to recreate what we did in 1969. Furthermore a significant chunk of the world doesn't even believe we landed on the Moon anymore, no doubt in part because of this apparent anachronism.

            It's not like there was any sort of collective or even singular decision to just let things die out. I mean sure Nixon did his thing intentionally, but even as a President in the golden years of the US, he was still just one man.

          • jodrellblank 50 minutes ago
            Basically everything collapses as far as it is allowed to, and the collapse is slowed only by:

            - profit, if a system generates it, people will keep the system running.

            - dilligence, usually driven by personal idealism, and unrewarded.

            - legal or financial penalties, or insurance costs.

            - it has collapsed to a temporarily stable state for now.

            For another comment I was looking at the Grenfell Tower fire in the UK around 2017 and the people who lived there had been raising fire risks for years and the landlord (management organization) and the council had been ignoring them, and ignoring the fire department. The companies which replaced the cladding on the tower with flammable cladding were choosing the cheaper flammable option and pointing fingers as well. And during the fire, the fire service had never dealt with such a big fire and didn't have a truck with a long ladder, didn't have extended-breathing gear, had radio problems, water pressure problems from the local water company (who deny that).

            This kind of backstory is typical for disasters, and for IT outages - and I've taken to believing that if something "should work" but wasn't tested recently then you should expect that it doesn't work. This is a common saying in backups (you need to test restoring), but it seems to apply everywhere. Backup internet connections that don't have enough bandwidth for the company to keep running. Disaster recovery sites that share resources with the production site. 'Disaster recovery' that recovered into a remote site, but they couldn't do CAD work remotely over their slow connection so it was still disastrous. Multiple power feeds but they were cross-wired so one failing still functionall took down everything.

            If knowledge transfer "should be happening" but it's not critical to a job, or it's not profitable, or it's not legally required and audited, then it isn't happening. Subject to the dilligent idealist employee mentioned above who are temporary in the long view. Management's involvement seems not to arrange the larger system to effectively shoulder responsibility, but rather find ways to avoid personal blame while cutting costs beyond the point where everything that needs to happen keeps happening.

          • onion2k 3 hours ago
            It’s the responsibility of the management to make sure the knowledge transferred to new generation.

            That's just lazy thinking, and probably a sign you've never been a manager. For all the responsibility to lie with management you'd have to be leading people who enthusiastically do what they're asked to do, raise problems, document things, follow processes, and make sure everything is handed over to the next person when they leave.

            That's not how people are. They'll have times when they're unmotivated, underpaid, grumpy, over-worked so they miss things, etc. That's when the organisational tech debt starts piling up, and there's nothing a manager can do to stop it except manage it as best they can even though they're under the same pressure, with the same lack of motivation and crap pay as everyone else.

            It's so easy to think you can fix it just by keeping on top of it and micromanaging where it starts to show up. It doesn't work that way.

      • philipallstar 6 hours ago
        > This is how we would end up with nuclear disasters, not because the technology is bad, but purely because of mismanagement and human negligence.

        I'm pretty sure constant upgrading would be more likely to cause disasters.

        • VBprogrammer 4 hours ago
          I can only imagine how much less reliable a modern JavaScript Electron app would be in this role...
      • cromka 7 hours ago
        If it's not broken, don't fix it.

        Same reason why MTA in NYC still operates subway using 100 y/o signaling hardware on most of the lines.

        In a way, your comment and the responses you get is a perfect allegory to inexperienced vs experienced engineering.

        • mitxela 6 hours ago
          Their 100 y/o hardware is built from stuff that's still produced though. We still make relays (not identical ones but ones that perform the same function), wires, and mechanical levers. The system's behavior is not encoded in the relays but in the connections between them. If you had a CPU made of separate transistors you could replace burned out transistors with any future transistors but if you had one made of chips you'd need those exact chips that were out of production.

          Replacing the relays in old telephone switches is a problem because they use so many weirdly specific types of relays - but those systems are only found in museums now. I believe track control uses fairly ordinary DPDT, etc., relay designs.

        • jodrellblank 2 hours ago
          But similar reasoning is why Canadian trams are worse than other countries, and it's not "good experienced engineering". In this nearly hour long rant by NotJustBikes[1] the section I've linked is about the technology and how the transit authority will not move on from 100 year old track technology which makes everything worse for customers. There are junctions where tram drivers have to stop and look at the track to make sure the junction is correctly set because the single-point switching is less reliable than modern designs. Or the driver has to stop the tram and get out to use a stick to move the track and change the junction because they aren't electrified. And then pass through junctions as slowly as 10km/h because the old track design has higher risk of derailment than modern designs.

          The designs for the electrified track switches were made by one company which was sold, re-sold, and then burned down and the designs lost, and there isn't anywhere else to buy them because nowhere else uses such old track design anymore, so not only is Toronto struggling to buy parts to continue electrifying the manual junctions, it's struggling to custom-make enough replacement parts to keep the aging electric switches working faster than they fail.

          And they were using trolley poles to connect to the overhead power lines instead of Pantographs until 2017, 50-100 years after everywhere else, which meant a) they couldn't get enough power through them to run air conditioning, and b) they are more likely to fall off the power line and the tram stops and the driver has to get out and reconnect them, and c) their newer trams now have to have custom dual-power connections to go through older parts of the network, and d) the carbon shoes on the trolley poles wear out quicker which means the trams are dirtier and taken out of service for maintenance more often in the wet which is when people want to use trams more.

          [1] https://youtu.be/HhQxNHrD6fA?t=2311

          • cromka 18 minutes ago
            OK, but the context here is IT I mission critical infrastructure, like energy or banking. These industries will not jump on the latest technology and will drag their feet for as long as possible.
        • sajithdilshan 6 hours ago
          > If it's not broken, don't fix it.

          I understand that way of thinking for a small business computer system. Not for a critical infrastructure. Also if people actually thought about like that we would still be in stone age, like why invent something new or use a new technology? Keep on using rocks to crack nuts and kill animals

          • sokoloff 6 hours ago
            I think you can imagine the difference between “I did some work and made this thing that is clearly better, but we might have a few kinks to work out” and “I did some work, and if I did it perfectly, it’s just as good as the old thing, but we might have a few kinks to work out.”
      • IG_Semmelweiss 6 hours ago
        Lindy's law:

        For non-perishable things - i.e technologies, ideas, books, institutions - the expected remaining lifespan is roughly proportional to how long they have already survived

        Time acts as a filter: what has already withstood a long stretch of disorder is more robust, so the longer it lasts, the longer it is expected to last.

        The old nuclear software running on mainframes have passed the test of time. The new software, has yet to.

        Nassim Taleb talks about this at length in his book, Antifragile.

      • cube00 7 hours ago
        > Why on earth wouldn’t the respective government spend money to modernize a critical infrastructure like a nuclear power plant?

        Same reason they don't modernize health care infrastructure. It's too expensive, people die if they get it wrong and they get voted out of office for their troubles.

      • mitxela 6 hours ago
        Now you know why "nuclear power may have been dangerous in the past, but with modern technology it's completely safe and Chernobyl will never happen again" is not a good argument.
        • idiotsecant 6 hours ago
          Now you know why making arguments from 20 year old anecdata makes you look foolish
        • sajithdilshan 5 hours ago
          Chernobyl didn’t happen because of technological blunder or even human negligence. It happened because poverty caused by communism in Soviet Union had to use old outdated (not the modern nuclear technology at that time) graphite tips in carbon rods because it was cheap and also kept it as a secret from the facility operators giving them a false sense of trust on the kill switch.

          Chernobyl is the perfect example to not use outdated old technology. Had they used the modern western technology at that time to upgrade their nuclear reactors the kill switch would have prevented the whole disaster instead of increasing the neutrons make the core a nuclear bomb.

          Next time educate yourself with facts before making a fool out of yourself

          • jodrellblank 2 hours ago
            > old outdated

            Wikipedia's pages on Chernobyl say that construction started in 1972 and the problem with the control rods causing an initial spike of power was discovered in 1983 ?

            [1] https://en.wikipedia.org/wiki/Chernobyl_Nuclear_Power_Plant

            [2] https://en.wikipedia.org/wiki/Chernobyl_disaster#Accident_se... (search 'Ignalina nuclear power plant')

          • HPsquared 2 hours ago
            Chernobyl was very much not "old", it was a more modern design than the PWRs which are built today. Chernobyl Unit 4 was also basically brand new, only 3 years old at the time of the disaster. The RBMK design dates from the 60s, whereas the PWR is from the 40s.
          • lukan 4 hours ago
            "Had they used the modern western technology" ... "Next time educate yourself with facts before making a fool out of yourself"

            But you are aware that this thread is about a reactor in the west, that "updated" their certified hardware to a VM instead running on windows NT?

            • mitxela 4 hours ago
              Everyone knows that all technology newer than Windows 2.0 will never be obsolete!
      • carlosjobim 4 hours ago
        There is no reason a more modern system would be better in any aspect.
    • TMWNN 17 hours ago
      >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.

      Vernor Vinge's A Deepness in the Sky depicts a human society thousands of years in the future, in which pretty much all software has already been written; it's just a matter of finding it. So programmer-archaeologists search archives and run code on emulators in emulators in emulators as far back as needed. <https://web.archive.org/web/20231114211656/http://www.gareth...>

      (Heck, recently I migrated a VM to its third hypervisor. It began as a physical machine a quarter century ago.)

  • bryanwi 28 minutes ago
    [Source: Was NT developer - have code in NT 4.0...]

    The big problem will almost always be some hardware dependency that breaks, almost always in I/O. I've seen video software used by TV producers that depended on an ISA (not EISA nor PCI, ISA) card to read NTSC input and impose text over it. And it broke as they were getting ready to add commentary to a live broadcast of a race (which I was driving in.)

    The world is full of machine tools and metrology devices that are stuck on some ancient computer/software because they made a weird proprietary protocol over the top of a centronics connector, or some other "WHAT were they thinking??" construction...

    All of these could be overcome with a new I/O device, and/or writing a device driver. So using say a raspberry PI that talks ethernet to your "monitor" PC is probably relatively change proof.

    If there is any documentation, if anybody can find said docs, if there's budget for a new I/O card and the device driver to go with it. Often the parties who have those resources would rather sell you a new machine tool, metrology machine, or I suppose, nuclear reactor (:-)

    Of course, certification is a big deal... A particular certification structure led to the 737 MAX tragedies. And since certifying authorities don't always have detailed tech knowledge of what things are, they have a hard time saying "no, you can't slide that by, you have to build and certify a new thing".

  • anonzzzies 23 minutes ago
    We have a client (a factory) I wrote a massive (for one person without AI) Clipper system for that runs the factory; this is decades ago but it just works and when they tried to replace it (not by us, but promises by others), it was worse and they did not switch. Cheating, but another client is a bank; they found its is really inefficient to not use DOS. Their machines use Windows but fullscreen DOS box you cannot close or minimize with the app in it.
  • yitchelle 3 hours ago
    Not MSDOS, but I feel obliged to shared the story of an auto shop in Poland using a Commodore 64 to run the calibration and wheel balancing some years back. It was viral news at the time but worth sharing again.

    https://www.youtube.com/watch?v=tXdLtnt-nvE

    Original Polish article - https://www.trojmiasto.pl/wiadomosci/Warszatat-samochodowy-z...

  • bryanwi 26 minutes ago
    AND more to the question - the contractor who remodeled my house in 2014 was still using some ancient DOS app, possibly running on a DOS machine or at least an emulator of one, to generate billing. Which was handed to me on paper....

    (He was a good contractor, so clearly having the latest billing software is not the deciding factor in that.)

  • rleigh 7 hours ago
    Not any longer. Back in the mid-2000s the company I worked for sold point-of-sale systems based upon a multi-user 4GL application (TAS Pro). Similar to dBase/Clipper etc., using the Novell Btrieve ISAM database engine.

    With the advent of USB and SATA we ceased to be able to source industrial embedded x86 boards which could run the application. At the time this was with Novell DR-DOS, which was relatively modern in terms of hardware support but still behind the times and we were struggling to manufacture new systems. The company was very small, so a full rewrite was investigated--I did a prototype using PostgreSQL and Gtkmm--but it wasn't realistic. Today, an AI could probably do a full rewrite in a day or two, including migration tooling. Back then, it would have been a multi-year effort for one person given the application's size and complexity.

    My solution was to run Linux since it had full support for the hardware. Debian Sarge at the time. This used a Perl frontend and dialog(1) to present a simple menu system at startup. This did backups, software updates (over dialup!), remote access for support (again over dialup), ran backups and ran the main application. It would start DOSEMU which provided the application with VGA display, COM ports and parallel ports for the application to drive "directly" (from its perspective). It also used Samba and CUPS to provide the DOS environment with shared network drives with exclusive byte-range file locking needed for the multi-user network database to work with concurrent users without data corruption, and also multi-user report printing and receipt printing.

    I left the company a year after this was put into full production, but the last I heard it kept the company viable with a supportable product for many years after until its owners retired. This kept software from the early 1990s running well into the 2010s, and there are likely still sites running it to this day.

  • shakna 18 hours ago
    dBase, MS-DOS 3.x, not using industrial anything. And as its a front of house tally machine, there's literally zero incentive to ever upgrade it. Downtime is measured in the yearly reboot, but there are non-operational business hours, so everything is just scheduled around that.

    We've already got it running on modern hardware. It's running under qemu. And the dBase stuff gets ripped out and sent to a REST server for broad monitoring and so on.

    We... Have one small oddity? There's a tape backup system, that throws everything through the soundcard. (Sound Blaster only.)

    Would be nice if onboarders didn't see dBase and just throw everything at AI instead of actually learning the skills they'll need when data migrations happen. But that's a people problem that can't be solved with tech.

  • proxysna 2 hours ago
    2014-2017 I was supporting a clipper setup for issuing work order and many other tasks for an old civil aviation repair plant. I’ve ended up virtualising and moving it to a hyperv cluster. Definitely the case of “if it works, don’t touch it”. Also set up a closed network for CNC machines to let engineers in the shop send jobs over the net instead of running around with floppies or manually entering gcode through the console. Fun times.
  • Felger 18 hours ago
    Not DOS, but I sold a '99 HP computer running win98 last month, to replace an identical failed system. It was used to control a 50 meters long custom industrial paint booth line for special equipments (like 57" rims). Luckily, their HDD was OK. Urged them to make a few sector-to-sector copies of it on a few spare HDD. This $100 sell surely has prevented this business from massive bills or even going bankrupt in the meantime from production loss.
    • adithyassekhar 7 hours ago
      Think that’d be worth more than 100 :)
      • Felger 1 hour ago
        I had it listed at this price for a few months, simeone from their company purchased it and rode 2 hours and half to come get it. Couldn't and had no reason to up the price at this stage. Indeed, this was a very good deal for them.
  • M95D 12 hours ago
    I had a functional STA Compact [1] coagulation analyzer until 2022. It ran a customized DOS version on a ITX computer board that was integrated into the analyzer. UI was in text mode and used the keyboard only. It had no mouse. The video in the link shows the UI for a few seconds at the end. We kept it functional as a backup and even used it a few days when the replacement broke down. It was one of the best analyzers I ever used.

    The newer version of that anaylzer, STA Compact Max [2] has mostly the same analyzer hardware, but newer ITX board inside. It runs Windows (XP, 7, 10...). Bugs galore.

    I know labs that used a Beckman-Coulter HmX hematology analyzer [3] until 2015 or so. That machine is attached to an external MS-DOS computer via a very thick cable and an ISA board. The cable connector looked a bit like a 68-pin SCSI-3. The software used VGA graphics mode.

      [1] https://www.youtube.com/watch?v=Kti6Zdyp8dQ
      [2] https://www.youtube.com/watch?v=MJan25vkpEA
      [3] https://www.soriaudio.com/index.php?mid=m_eqp&document_srl=62138152
  • freddealmeida 2 hours ago
    An old story. I used to work for Fox Home Entertainment (CDs etc)this is 20+ years ago. And we had proper DOS running on old machines. We used it to do all our finances (including all of Japan, Asia sales). Most of the money we made on movies like Titanic were tracked on DOS. Until about 2003 if memory serves me where we moved to SAP. Why this was worrisome was how easily fraud occurred. In my tenure there $5-10M was stolen. At the time sent to companies in Brazil. I'm still surprised by larger firms where they keep these things alive to retain the data. CocaCola did it. A few large Insurance firms too. Crazy.
  • jjbinx007 3 hours ago
    Not DOS but we recently had to virtualise a Windows XP box as it was running crucial software for a visitor attraction. The software was written by a member of staff who sadly passed away and the PC it was running on was approximately 20 years old.

    We managed to virtualise it and then run it in a VM, and it needed a couple of USB-to-serial adapters passing through as well.

    We're also finding some kiosks are running Shockwave Flash apps provided by companies that are no longer trading. We can decompile the files to extract the assets but at some point it's easier to just replace completely.

  • foofoo55 2 hours ago
    One of our vendors is a contract electronic manufacturer (circuit board stuffer) that has a wave soldering machine running MS-DOS on a PC that's built into the control cabinet. It uses the parallel port to communicate with Opto22 industrial i/o modules, which then is wired to all the temp sensors, relays, etc. It just keeps working.
  • bradleyy 1 hour ago
    I know a shop that still runs an Apple ][: they have a Numerical Control machine. For those who don't know, NC is the predecessor to Computer Numerical Control, i.e. CNC machines.

    They run on punch tape.

    So this Apple ][ is connected to simulate the punch tape reader, and send the (I think) G-code commands to the machine. So it's now a CNC, managed by an Apple ][.

  • Aldipower 6 hours ago
    The Detusche Bahn still runs DOS and Window 3.11 in their ICE I trains! They searched for admins 2 years ago. https://www.tomshardware.com/software/windows/ms-dos-and-win...
    • tefkah 6 hours ago
      i don’t want to say this explains things, but i do want to imply it
    • carefree-bob 5 hours ago
      You should check out the NYC subway, which has electromechanical relays, cloth covered wiring, and pre-WW2 analogue panels.

      They do not even have an OS!

      • driverdan 1 hour ago
        That's far superior than running an outdated general computing platform. Electromechanical devices are simple, easy to understand, and replaceable. It may be harder to diagnose problems but with maintenance it will work forever.
        • _trampeltier 1 hour ago
          +1 from me for relais technique. It is easy to replace, even in 1000 years. Today PLCs are great and fun. We can do a lot of cool things with them. Just with the short and shorter life cycles, sometimes even less than 10 years. If something breaks you have to replace so much stuff for a small broken piece. Thats such a bummer in todays industrie automation.
  • londons_explore 18 hours ago
    This thread reminds me that there is a huge benefit to using a super common OS+hardware.

    In 30 years time it will all be outdated... But emulators will exist and a business process in 2050 that still depended on something I built today could still run with minimal effort or risk.

    • chr15m 16 hours ago
      If you have the source code it's going to be a lot easier to continue.
      • hulitu 7 hours ago
        It depends on the gcc/llvm version.
  • MarkSweep 18 hours ago
    A company I used to work at still ships a piece of hardware with an Intel 186 microcontroller in it. The compilers are 16-bit DOS applications and the tool to program the DIP packages with the program was also a DOS application. I’m not sure what the physical interface between the programmer and computer was.
  • alexpotato 3 hours ago
    Not DOS but another dad in my town works for one of the opera houses in NYC.

    They have what are called "supertitles" [0] so that people can follow along with what the opera singers are actually saying. There is one on the back of each seat in the theater.

    As near as I can figure, it's basically hundreds of LCD displays on some kind of bus network and connected to a computer via serial connection aka "D pin connector".

    The software only runs on Windows XP and he has to keep finding old Windows XP machines on eBay in order to keep it working. I think he also has a couple hard drive images of the working OS + software.

    I had suggested using a USB to D pin adapter and then use an LLM to sniff the protocol and then reverse engineer it.

    His response:

    "It HAS to work correctly. In 30 years we've never had an outage with the old system."

    0 - https://en.wikipedia.org/wiki/Surtitles

    • indrora 2 hours ago
      Ah, that sounds like it's The Met, who have a bespoke electronic libretto system.

      You're right, it is a bunch of LCDs on a bus (iirc rs485).

    • icantevenhold 2 hours ago
      Couldn’t you install a cracked windows xp on any kind of machine essentially? Or what is special about “windows xp machines”?
  • mikewarot 11 hours ago
    The Gear cutting job shop I worked for had a CNC lathe running with a GE Computer from the late 1970s that stored data on punched Mylar tape, until it was bought out in 2019.

    The bevel gear generator setup was some formula calculations running in version 1 of TK!solver, which would have been a $5000 upgrade to get the latest version, so they ran them under MS-DOS in DOSbox, and saved the grief.

    Without that software, they would have to pay Gleason $500+ to do the calculations for each new gear setup.

    There are strong and reasonable reasons to keep very old systems alive in offline production environments.

  • pumplekin 7 hours ago
    Not DOS, but two similar era cases.

    A FTSE 100 company I used to work for, still maintains a SCO UNIX machine that was first installed in 1993. It hasn't had any upgrades since, has specialist hardware in it, and still has an IP stack that is classful (ie. no subnet masks, 10.x.x.x is always a /8). It runs in a 100% airgapped network, and it isn't essential to keeping the core companies operations, but it is a ticking time bomb nobody seems to want to address that will cause a lot of distruption when it finally dies.

    Also I was recently (very lightly) involved in a consultancy project to remove an OS/2 based point of sale system for a small local retailer with 6 stores.

    • adithyassekhar 7 hours ago
      If you don’t mind me asking, how can a thing that causes disruption when it dies still not be considered essential?
  • dazhbog 8 hours ago
    I run 2 old Juki pick and place machines. They run DOS 6.22 on a 486 I think. My biggest pain points are, 1) booting them up without errors, and 2) transferring files to them wirelessly without any floppies. (without installing any DOS software)

    Closest I got was with a GOTEK and an ESP32 emulating a USB. But it was flaky so I dropped it for now.

    • mistyvales 2 hours ago
      Would a Grease Weasel work for that situation?
  • Sleaker 18 hours ago
    The last company I worked for still had customers they were dragging forward to get upgrades from coax connexted green screen terminals to modern network thin clients. It wasnt on DOS, but very old unix OS, tape drives for backups, parallel for printers, serial for scanners. No USB. Lovely troubleshooting when you were dealing with 30+ year old hardware setups. There was only one company that would even servicenthe green screens if they failed, and you couldn't buy them anymore.
  • andix 19 hours ago
    I had to keep an old clipper/dbase application running until recently. It worked perfectly seamless with vdos (vdos.info). It's commercial software, but very reasonably priced. Dosbox is another alternative, but didn't work as well with printing and I think also wasn't able to do row locking of dBASE databases over the network.
  • 83457 18 hours ago
    My dad ran a commercial 2-way radio business. There were multiple radios with programming software that would not work on anything above a 386 and DOS. He had a couple computers from the late-80s running for nearly 25 years, though I think he had to replace one of them with another of similar vintage. Also, had a 486 that he used for customer notes in WordPerfect up to about 2015.

    I suspect he could have found a way to use a newer computer, but if it ain’t broke…

    • betaby 16 hours ago
      Intel was seling 386 CPU up until 2007. I personally was using brand new special equipment with 386 soldered to custom MBs with no VGA, serial only access. I suppose you can purchase such boards from ebay/recyclers today.
    • Froedlich 16 hours ago
      I still have a circa-1996 486 running Windows 95. It has an EPROM burner card and software that I use to reprogram the ECM in my car.

      The cost of upgrading to modern software and hardware is substantial, plus the learning curve for something I only do rarely nowadays.

  • _trampeltier 16 hours ago
    Siemens Field PG. It is a rugged Notebook for PLC programmers. At least in the last version until last year, the "Field PG M6" was possible to buy the Notebook with a special serial port for old S5 PLCs ant the Step5 software came in a special DosBox version with it.

    The Field PG has also another special port called "MPI/Profibus" for S7 PLCs, 2 Ethernet ports and a DVD drive.

    https://support.industry.siemens.com/cs/document/109766662/d...

  • sgerenser 19 hours ago
    Does the idea make use of https://86box.net? Just heard of this recently on hn and it seems promising for anything that requires low level/cycle accurate emulation vs. your typical high level emulator.
    • Felger 1 hour ago
      It should work with Siemens MPI/PPI interfaces, but I predict issues with ex-Telemecanique (now Schneider Electric) unitelway realtime DOS driver which is extremely picky.
    • mlaux 18 hours ago
      My idea is a DOS emulator with a really thorough log of every DOS interrupt called and I/O port interacted with. This could then be used to automatically, say, insert rows into a sqlite table when the DOS app updates a .DBF file, or forward GPIB data to a modern USB adapter. I wanted to avoid low level/cycle-accurate emulation as much as possible, only adding quirks as needed to support the most popular business application suites.
  • fires10 17 hours ago
    I work at a multi billion dollar facility for a Fortune 100 company and we still depend on DOS. Keeping the mandatory DOS machines going is an exercise. Especially integrating them into modern systems.

    Edit: There is no required hardware, however maintaining a stable serial connection through a VM and timing issues due to faster hardware has been fun.

    • mlaux 16 hours ago
      The serial port stuff is very close to what I'm working on - what's on the other end of the connection? What does "integrating them into modern systems" look like for you: getting data out/pushing data in/both?
      • fires10 16 hours ago
        We typically integrate them by encapsulation. Building multiple layers of more modern systems for them to communicate through. A combination of Windows and Linux boxes. The other end of the connection is very old industrial equipment. This is not to run the equipment per se but to configure and program it.
    • 1over137 16 hours ago
      Actual MS-DOS or FreeDOS?
      • fires10 16 hours ago
        MS-DOS or Windows 2003 running DOS vdm.
  • Froedlich 17 hours ago
    Me!

    I have a client with some business software that runs on DOS. They have a dozen seats. A single Linux server gives serves a dozen VNC sessions with the software running in DOSEMU. Printing is done with the Linux print stack and three Ethernet print servers.

    It has been working without a hitch since 2008. Oh, so has the server, which is a VirtualBox VM.

  • andix 18 hours ago
    Just out of curiosity: is it possible to somehow attach an ISA Adapter via USB to a VM? ISA does depend a lot on DMA and timing, but the clock is only 8 mhz and gives a software layer on a modern cpu a lot of time to do stuff between ISA bus cycles.

    Keeping old hardware running is very fragile. Most spare parts are decades old now too, and nobody knows if they still work properly.

    • Teknoman117 18 hours ago
      To a VM? Possibly.

      The DMA might actually be the easy part.

      The main concern is how many VM exits per second a modern CPU can handle. Even though the interface is "slow", you can probably do ~500k to 1 million IN/OUTs or MOVs per second to ISA. You'd have to trap (VM exit) every access to a IO port or memory within the ISA window.

      During the pandemic I cobbled together a KVM-accelerated emulator for an old 386EX based board I had and trapping every memory access to IO was slower than the real hardware.

    • lysace 18 hours ago
      USB and VM latencies are both questionable here, I would think.

      ISA motherboards still work and have been mass produced in the hundreds of millions. (I have about a dozen in my retro closet.)

      The esoteric ISA expansion cards would be the bottleneck, not the motherboards.

      • andix 18 hours ago
        All those layers add some latency, but 8 mhz is really slow. USB 4 can do extremely low latency, otherwise PCIe over USB wouldn't work.
        • labcomputer 14 hours ago
          The problem is that a lot of those old ISA drivers were peeking and poking card registers as fast as the bus would allow, which was over 1 MHz (less than 1 microsecond per transaction), not DMAing data to RAM (though some did that too).

          With a modern 4 GHz CPU, that means your budget is only 4000 clocks per interrupt. The context save alone can make it hard to hit 1MHz, and you really want to have your interrupt code pinned to the L1 cache because a few memory reads will blow your entire budget.

          As nice as USB4 is, I’ve never heard anyone claim it has single-digit microsecond latency, to say nothing of sub-microsecond latency. The typically-quoted ~20 usec latency of USB4 limits it to around 50 kHz for an emulated ISA card.

          • rdtsc 13 hours ago
            Often people confuse latency vs throughput/bandwidth. With streaming and batching USB4 will shuffle a lot data through on average per second. But it will never hit reliable microsecond level or even submicrosecond latencies.

            At the same time ISA card will never reach 40Gbps throughout with CPU clocking at tens of MHz only or often less.

        • lysace 18 hours ago
          This looks quite interesting:

          https://www.reddit.com/r/vintagecomputing/comments/jbaw38/is... (2020)

          ISA-over-USB, using real ISA cards in an emulator

          https://github.com/Manawyrm/ISASTM/

  • throwup238 3 hours ago
    I don’t know the specifics of their systems but both of my local lumberyards here in SoCal still use DOS systems for their point of sale and inventory management, with slow dotmatrix printers and everything.

    They simply have no reason to modernize. The one big benefit they’d have is an online inventory system but they make most of their money from negotiated bulk orders so there’s zero incentive.

  • ynac 19 hours ago
    It's not totally for business, but I run some antennae and radio telescopes that feed through a Gateway 386/33/16MB RAM. As well as a Getac, no idea what model, but it's from the early 2000s. They both feed through to a A/B switched Paradise CRT (so cute). dBase is on the list.
  • zdragnar 18 hours ago
    It's been a few years now, but I know a major manufacturer had some windows XP boxes around because they were the newest hardware/software they could get with native parallel port support to interface with their machines.

    To give you an idea of the complexity of the manufacturing lines, shutting the machines down and starting them back up again was measured in days. Upgrading them would be obscenely expensive, let alone replacing them, just in the opportunity cost of not making anything alone.

    • mgk123 7 hours ago
      For anyone that needs true native serial & parallel ports, a Dell Latitude E series laptop (or Precision 7xx0) with docking station is an easily-available option.

      The last machines with dock port have 6th gen Core CPUs (Latitude E5x70), or 7th gen for Precision 7x20.

      • rkagerer 3 hours ago
        Not as pure, but for what it's worth I've had success with a Syba SD-PEX50023 in applications where USB-based parallel port emulation failed.
  • AugustoCAS 2 hours ago
    I don't, but the abbey at the city I live has an ancient PC running a program from the 80s that controls the bell ringing.

    I recall seeing it connected via a parallel port to a large board that then operates the switches/relays of the hammers.

  • nanochess 19 hours ago
    I've an AMD K5 processor machine running at 100 mhz. for testing Transputer ISA cards when someone buys one, I also use the same machine to format and copy my Pascal compiler into a pair of 5 1/4" floppy disks. All using DOS.
    • bartread 19 hours ago
      > Transputer ISA cards when someone buys one

      Your use of “when” is interesting - suggests it’s not that occasional. Wonder what people are doing with these nowadays.

  • NBJack 17 hours ago
    Do scanners count?

    I'm pretty sure they moved on from them, but a while ago I did seasonal work for a company that rented out scanners for year end inventory (tax related, IIRC). The scanners had to be "cooked" (flashed) on racks, boxed, and sent. The flashing usually worked, but on occasion, the scanner would fail the checksum or something and drop you into a DOS prompt.

  • EvanAnderson 8 hours ago
    A Customer of mine has an 386 machine with an ISA interface board connected to an optical comparator instrument. I believe they also still have some MS-DOS-based computers connected to CNC machines, too.

    I have two Customers who use DOS applications under DOSBox (a Clipper-based accounting package at one, and a Symantec Q&A-based application at another).

  • saidnooneever 11 hours ago
    i know still some accountant who use a DOS program to do his work because he hates the fact modern UI has load times. slows him down too much o.O (his program is all keybinds).

    i do not have exp myself but i found it a delightful reasoning. i told him modern PC could also do the same on modern OS (ncurses or ratatui or so maybe) but that if he ask a programmer to make an upgrade he'd need to find the right kind of guy. He had someone do it few times but they came back with web interfaces.

  • amelius 6 hours ago
    I bet most AI is capable enough now to migrate you away to some emulator for a few dollars.

    And I would even bet that in most cases you could run a solution on a sub $10 board from aliexpress.

  • sse 2 hours ago
    I do, for two clipper programs. But no extra machine, just a VM. Until not long ago, it was running without VM on 32 bit Windows 10.
  • Kuyawa 3 hours ago
    One interesting thing of living in the AI era is that every single one of these old apps (that people still use and never paid big money to upgrade because it it ain't broke don't fix it) can now be rebuilt for $5 in ten minutes if you really know what to do (YMMV)

    If you don't know, you'd have to pay an expert big money to do that and the migration abandoned just like before, so another decade will go buy until AI does that without permission just because it found a possibility for optimization and it is instructed to do so without human approval, because governments

    • tclancy 2 hours ago
      Absolutely. And run faster, cheaper and safer.

      Just as long as you still have all the documentation and the spec was done right and updated as things changed over the whole lifetime of the system up to now. And a good test harness. And industry-specific knowledge.

    • asciimov 2 hours ago
      You would think so, but most of the low hanging fruit has already been rewritten and replaced. The biggest hurdle is hardware lock in, ISA boards, hardware keys, or other hardware interfaces that can’t be easily connected to new systems. Never mind the problem of verification. That app that takes days to rewrite can annoyingly take months to verify.
    • reddozen 2 hours ago
      > if you really know what to do

      The so called "load-bearing gap" you pay experts for.

  • CobaltFire 18 hours ago
    I had to keep a disturbingly old machine with GPIB running until a few years back. They are still in operation in Australia (who we sold them to).

    It was a test/repair bench for military aircraft avionics, with the only flying platform left using it being the legacy F/A-18 (A/B/C/D). Harris H-100 minicomputer hooked to an HP terminal and several full racks of GPIB test equipment with half of a rack of solenoids for switching between stimulus and response and which pin.

    Not what you asked, but the question brought back memories.

  • boelboel 4 hours ago
    I've seen some older retail stores use DOS machines, ones where the owners are 70+. They just don't have a reason to upgrade what they're used to.
  • smackeyacky 19 hours ago
    I know of a DOS machine at a wool testing place that uses an ISA card based imager for measuring the micron and other things. They also have a supporting DOS machine with a dBase looking database on it. When I spoke to the owner he didn’t really understand the risks involved in running ancient hardware and in fact had a storage room with period PCs in it if the machines failed. He didn’t have much of a backup plan for the imaging hardware though.

    My opinion is that if these guys are still running this gear, they already have a strategy in place (no matter how flawed) and would likely retire before throwing money at something they consider a non problem.

    Good luck with the idea. It likely is a tiny niche market with customisation for every customer and given they are normally hardware constrained AI may not be much of a help.

    All of them have no money as well.

    • mlaux 18 hours ago
      My idea is basically a DOS runtime with hooks on interrupts and I/O that would allow for either migrating databases to modern formats, or converting I/O accesses for modern USB peripherals. Customization for every customer and AI not being much of a help are pluses for me... lack of money not so much.
      • Froedlich 16 hours ago
        I have been porting sections of the business software I mentioned earlier from QuickBASIC on DOS (nice to have the source code!) to Tcl on Linux using ChatGPT to automate the conversion. It gets it right the first try, almost every time.

        The BASIC code is very simple by modern standards, and Tcl overlaps BASIC neatly, making conversion easy.

        Unfortunately it's just a short-term stopgap to add some features management suddenly can't live without, that weren't practical to implement in BASIC/DOS. They'll replace the whole stack with a commercial product and support contract when they find something they like.

    • Dwedit 19 hours ago
      You can still get ISA slots on systems as new as Broadwell with an adapter.
  • ksec 12 hours ago
    We were talking about Visual FoxPro only a few days ago. [1] And one of those same companies in my comment [2] uses an old ordering system that is still in DOS and they boot up a VM to use it. They still have a printing machine ( not a normal printer ) for those order printing connected via a Parallel Port. I don't know the details of how that works though.

    And by the end of all that, the order will be Faxed. Manually.

    Did they tried to email it or automate it. Hell yes. Did it work? No.

    [1] https://news.ycombinator.com/item?id=49808023

    [2] https://news.ycombinator.com/item?id=49811716

  • deathgripsss 3 hours ago
    Still have a liquid scintillation counter running on DOS with raw data printed on a dot matrix
  • ChrisMarshallNY 7 hours ago
    I did, for a while. Then, I used VMs. I haven't had a Windows VM for years.

    If I were a serious gamer (I'm not), then I'd get a hardware rig, but otherwise, I've not needed it.

    I had a doctor that kept an original NT machine, for many years, because his bespoke app worked on it.

  • rjh29 5 hours ago
    Not recently but when I was a teenager (2001-ish) my supermarket was using a DOS computer to handle stock, print new labels when prices updated each day, etc.
  • womod 17 hours ago
    We keep a FreeDOS machine at work for dialing in to configure and service paging terminals and using old two-way radio programming software.

    Most of the stuff I've moved over to run in DOSbox but it's still in use occasionally for the software that's difficult to port over.

  • myself248 14 hours ago
    A few years ago, I helped repair a broken USB port, on a USB-floppy emulator...

    ...which was so the operators could sneakernet their NC tape files into an IBM PC 5150 that thought it was talking to a floppy drive, of course...

    ...which hosted an ISA card that emulated the punch-tape reader that the NC lathe had originally been designed with.

    The NC lathe hadn't missed a beat in 50+ years, why mess with what works?

  • DASD 19 hours ago
    Perhaps look into environmental services labs that do contract EPA work. I would not be surprised to see entire HP-Agilent(ISA-carded) - (think liquid chromotography analyzers) fleets that would match what you're looking for.
  • alightsoul 18 hours ago
    You're trying to create and sell a version of dos box? These companies have not replaced their computers because to the user there is no separation between the computer and the machine it controls. So the computer will be updated along with the equipment, which is not connected to the internet or a network anyways so it's not a cybersecurity risk. For the user, if it runs fine, there's no need to update just the computer, and the computer is updated along with the machine

    In other words, these are embedded systems.

    • mlaux 18 hours ago
      Not exactly, freely available solutions are already good enough for people who just want to run their apps on modern hardware, and have been for a long time. What I was thinking about writing is a tool that eases migration by using interrupt and I/O hooks to detect common patterns and, say, builds a modern SQLite database as the business uses their dBase program. Whether anyone actually needs this, I don't know.
      • alightsoul 15 hours ago
        There's a few car dealerships that still use databases from the 80s. As for why they haven't migrated, I'd guess must be reasons I'd assume at this point it's a choice they have made
  • techteach00 12 hours ago
    It's not DOS but my private school still uses an IBM 5100 to do payroll and record attendance.
    • roryirvine 4 hours ago
      What's the reason for not using a more modern MIS?

      (I can certainly understand why organisations with niche requirements might hang on to old systems for as long as they continue to work, but I'd have thought that school payroll and attendance were much too commonplace to fall into that category)

      • techteach00 4 hours ago
        I'm kidding. BRO, no school would be running the first (imo) commercial desktop still in the year 2026. The machine I cited was released in 1976!
  • zerr 7 hours ago
    I've stumbled upon DOS on the LCD screen of the otherwise seemingly modern gas station.
  • Postosuchus 17 hours ago
    This is probably a wrong audience. Most people here are very technical - the kind that would not put up with tiptoeing around a sacred computer from decades ago running some magic software from the DOS era. This crowd will aggressively move it to modernized architecture or at least emulate it using a more modern platform.

    The company I worked at in the late nineties, used Managing Your Money (MYM) for bookkeeping - initially on a dedicated DOS machine. My colleague set up a DOSEMU-based emulator and moved the software to it (bye-bye, dedicated DOS machine!). Later, he re-wrote it in STk (Scheme w/ Tk bindings, running natively in Linux) as ageneral-purpose transaction storage. ¯\_(ツ)_/¯

    • fires10 16 hours ago
      This is not always possible when the systems are validated and regulated.
      • jlarocco 13 hours ago
        Yeah. Sometimes old hardware forces its hand and causes a big PITA.

        I had a job working on VAX/VMS around 2009, but it was actually an emulator running on a PC because they just couldn't find any hardware to fix the VAX. At some point before I joined they had to get a ton of government approvals to use the emulator.

        Fortunately they had a project to modernize the whole stack. And it was going to Solaris :-/

  • gerdesj 18 hours ago
    Until recently several customers have an industrial machine that boots DOS. I think the oldest effort we deal with is Win XP now. I do have a C>64 at home ...

    In a world that requires security audits etc here's some notes that might help:

    Scenarios: You have a device that only talks NetBIOS or even NetBEUI for file sharing. You need to get files to and from it and your CAD workstations run Windows 11 and anything less than SMB 3, with signing and sealing and all that jazz is laughable.

    ... Devices requiring ftp, telnet, serial over carrier pidgeon

    Solution options:

    Networking: The first job is to segregate your industrial gear from your general network and you might want to create two or more industrial gear and internet of things type networks with differing access policies. Start with one for now, you can improve it later.

    You use 801.1Q VLANS logically or physically (why the hell did I want to write literally?) separate via separate switches.

    Please do not skimp on this step. Buy a network bod to sort it out or put your IT bod on a course or hopefully they will have labbed this up at home already!

    Comms: Samba is bloody wonderful and speaks everything that MS has ever done and deprecated. Even Samba does need to be asked to start speaking some of those dialects again but it will.

    Put a Linux (other Unices are available) box on the same VLAN as your machines. You will need to set quite a few options relating to the minimum version for its server version. When talking to the machines, Samba is the server and when talking to your file server, Samba is the client.

    Create a data share on a Windows box on the corp LAN. For example it might be on a file server for multiple access or just a single CAD PC.

    Get the Samba box to mount that share to itself at say /srv/data_share_mc1

    Now get the Samba box to create a share from /srv/data_share_mc1 which it calls DAT_MC1 (8.3 chars for NetBIOS)

    With luck, you should be able to map DAT_MC1 on your machine.

  • lormayna 11 hours ago
    Few years ago I was working for a F500 company and during an assessment we discovered couple of OS/2 Warp machines that were controlling CNC equipment
  • nickhalfasleep 16 hours ago
    I know of some laboratories where they have a host of old machines for software to support some critical instruments that only runs off a dongle or an ISA card and it still does accurate work.
  • reaperducer 19 hours ago
    Not DOS, but my company has a Windows XP machine with a dialup connection that I have to keep running for obtuse legal reasons.

    If it goes down, the company gets fined. It happened in the gap between my predecessor leaving, and me being hired.

    • gerdesj 18 hours ago
      Does it have to be a XP box or is just keeping a serial dialup connection working the key?
    • andix 19 hours ago
      Is it a physical machine and not a VM? I already had issues with getting XP compatible spare parts years ago. Had to buy used parts that were already pretty old (so high risk of failing again).
      • reaperducer 18 hours ago
        It's a physical machine.

        Fortunately, I don't have to deal with swapping parts. There's an outside contractor on call 24/7 for that.

        The last time I saw it was about two years ago when I taped yet another piece of paper to the filing cabinet it sits on reading "DO NOT TURN OFF UNDER PENALTY OF LAW!"

        Someone keeps taking the paper down.

        • andix 18 hours ago
          Put a proper sticker on, that can't be removed easily.
  • mococa 2 hours ago
    Not now, but few years ago I worked on a toll that runs DOS because… yes.

    Also worked ~2014 DOS slot machines - in next year we ported to Linux

  • newman314 18 hours ago
    I virtualized a bunch and they seem to work well. At one point, I even had Ultima running on one. =D
  • al_borland 19 hours ago
    It’s gone now, but we used to have a random OS/2 box well past the point where that was extremely weird.
    • gerdesj 18 hours ago
      What's weird about Warp?
      • Froedlich 16 hours ago
        Like most people who bought into the OS/2 hype, I bailed after 1.3.
      • al_borland 14 hours ago
        The weird part was still using it into the 2010s.
  • Natsu 16 hours ago
    I used to be doing that, but this was a bit over a decade ago at this point. There was an SBC with DOS on a chip that connected to Novell Netware. I set a few variables in autoexec.bat, let it connect to the network drive, then had it run a script from there to admin them / do backups (by which I mean xcopy the C: drive).

    These were for some industrial CNC machines with a poorly version-controlled app (send us the single-file .c for the program, we'll make changes & recompile for you, then send back a new .c and .exe file) that would just malloc() all the memory on the machine for a million element array instead of tracking the 1k or so unit IDs a more efficient way. They were six digits long, it worked... mostly.

    I kept a 3.5 floppy with the contents of sys a: that I used to run sys c: after restoring a machine from backup in my office.

    EDIT: oh, and of course by "restoring from backup" I mean reversing the xcopy to copy everything from the network drive's copy back to C:

    EDIT2: My memory is going, they didn't use malloc() at all, anywhere in the programs, they just had a static million element array.

  • api 16 hours ago
    Not current and not DOS... but years ago, around 2011, I helped set up a series of QEMU emulators running DEC Ultrix and MIPS Unix software that called out and retrieved data from weather stations only reachable by modem. The software had been written years prior in C and nobody had the source.

    The box running the QEMU emulators had a bunch of old US Robotics modems hanging off it via USB serial dongles.

  • TMWNN 17 hours ago
    >Anything with a parallel port dongle?

    https://news.ycombinator.com/item?id=46849567

  • ironqcold 15 hours ago
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  • Aeolun 7 hours ago
    In the AI era, can’t we just release a new version of DOS?