A few years ago i used it for automated builds. The GUI bits were (and i think still are, at least last time i checked it a couple of months ago) broken, but the command-line works fine and for automated builds it worked perfectly.

To what benefit, could you share?

Running Windows builds and tests where Wine didn't work but ReactOS did?

This might be motivated by Windows licensing regime. Licensing for Windows VM instances used to be super-painful, so people would try hard to avoid it.

IIRC, to run a Windows VM you were required to acquire Windows Datacenter licenses for every node capable of running that VM (at least that's what we were told). If you have a fleet of hypervisor nodes running Linux workloads, the licensing cost calculated for a single Windows VM was absolutely ridiculous.

I guess things are less insane today and you can just get a license for the guest OS, no matter whether it's running virtualized or bare metal?

Familiarity, mainly. The tools i used were Windows binaries and i knew how to set them up under Windows (although it took a couple of tries under ReactOS due to GUI freezes, etc, but this was in a VM image that i'd later reuse as a sort-of blank state for each build - note BTW that this was like 6-7 years ago), whereas at the time i felt a bit skittish using Windows development tools under Wine.

It’s free

Good question. I understand the motivation behind it and am impressed with the work done but can't imagine it being used as someone's primary os.

We use it on a Bitcoin ATM that converts spare pocket change to BTC (think Coinstar) in order to avoid licensing issues with Microsoft and Windows CE.

Are you using existing ATM software that was written for Windows, or was this custom development (i.e., did you choose ReactOS over Windows, or over e.g. Linux)?

The hardware drivers for the coin counting ATM machine were provided as precompiled WinNT/CE drivers by the vendor without sources and using ReactOS was easier than reverse engineering them all.

A wrote up about this would almost certainly make the front page of HN.

Not that that should be the primary motivation for writing it, but surely the validation won't hurt! Projects like these are the most interesting ones for me to read!

That's really cool and IMO a great use case for ReactOS. Sounds like a neat project. Did everything just work out of the box? If so that's pretty impressive on the part of ReactOS.

Seems like a pretty reasonable use case. Thanks for sharing!

That is pretty interesting

At home, I would not consider it because it is a Windows clone, and I have certain, strongly-held views on Windows. ;-)

At work, the problem is different - even if ReactOS achieved 100% bug-for-bug compatibility with Windows 10, using it on client PCs would be too painful, because every time some application misbehaved, there would be that lingering doubt if the problem is with the application itself or with the OS. And if you called some software vendor's support hotline, the moment you let it slip that you are running something that is not Windows, they would start laughing and hang up on you.

There are scenarios where I would consider a Windows 10-compatible ReactOS at work - e.g. for reviving a PC where the "native" Windows version has gone out of support, and it only needs to run MS Office or Windows' RDP client, or a browser. But in the five years I have worked as Windows admin, this has happened so rarely I doubt it would matter a lot.

If the project got to the point where ISV's support hotlines did not care whether you are running MS Windows or ReactOS, ... that would change things in a big way.

I feel like I should launch it in a VM and start using it for some of my Windows tasks just to see if I can. I wonder if it can run WebEx..

I would assume you can run WebEx because ReactOS says they have 100% binary compatibility with Windows.

What you’d need to run any Windows program is a way to parse the PE executable format, load it into memory, and emulate or simulate W32 api calls. I’m sure there are other steps but I can’t think of many more off the top of my head.

Well, for that you just use WINE. ReactOS goes a lot further.

I don't use it, but I do have an installation on an older computer around here and I occasionally browse through the source code because what these guys managed to build is really damn impressive.

Tried it on one of my old netbooks, unfortunately it can't install from USB anymore at the moment. (I do have an old celeron 500 laptop too but it can't read CD-R)