[ch_123]

> That's much more relevant to industrial applications where some device is controlled by an ancient computer because the vendor originally provided drivers for NT 5.0 or 5.1 which don't work on anything modern.

In most of those applications, you just leave the computer be and don't touch it. In some cases (especially medical devices) you may not even be allowed to touch it for legal/compliance reasons. If the hardware dies, you most likely find the exact same machine (or something equivalent) and run the same OS - there are many scenarios where replacing the computer with something modern is not viable (lack of the correct I/O interfaces, computer is too fast, etc.)

If there were software bugs which could impact operations, they probably would have arisen during the first few years when there was a support contract. As for security issues - you lock down access and disconnect from any network with public internet access.

All that assumes that ReactOS is a perfect drop-in replacement for whatever version of Windows you are replacing, and that is probably not a good assumption.

[ACS_Solver]

In my experience, things like ReactOS would have been more useful in parts of the world with let's say a less thorough approach to things like compliance.

A factory has a CNC machine delivered fifteen years ago that's been run by the same computer all along. The computer eventually gives up the ghost, the original IT guy who got the vendor's drivers and installed them on that computer with an FCKGW copy of WinXP is long gone. Asking the current IT guy, the easiest solution (in a hypothetical timeline where a usable ReactOS exists) is to take the cheapest computer available, install ReactOS, throw in drivers from the original vendor CD at the bottom of some shelf and call it a day.

[ch_123]

We might have to agree to disagree here, but I think the scenario where the IT guy uses XP and "finds" a license for it is the approach I would take if I was put in this situation. If the vendor for the CNC machine certified/tested their machine against Windows XP, and does not offer any support for new operating systems, I would be very reluctant to use anything else - whether it is another version of Windows which could accept the same drivers, or an open source clone. Again, I'm assuming that ReactOS manages to be a perfect clone, which is may or may not be in practice.