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

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.

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...

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.

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.

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.

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.

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.

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.

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.

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)_/¯

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.

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.

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.

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.

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.

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.

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.

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.

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.

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…

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.

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.

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.

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.

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.

I virtualized a bunch and they seem to work well. At one point, I even had Ultima running on one. =D

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.

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.

>Anything with a parallel port dongle?

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

It’s gone now, but we used to have a random OS/2 box well past the point where that was extremely weird.