ReactOS

I see what they did here, but did you? ReactOS is still unknown among many, and it could use more developers, so I'm spreading the word, and you should, too.

ReactOS not only allows you to learn a lot from Windows, but it'll eventually become very usable as a free, open source OS that runs Windows software - a free, open source Windows replacement.

Besides, after Windows 2000 and Windows XP are totally phased out and we don't get drivers for them, we'll be forced to move on to Vista. The problem is not the scary amount of bloatware built into Vista as much as it's the fact Windows Vista is Windows DRM. Unless people finds a way to crack away the digital rights infringement so built into Windows Vista, we'll have to move to ReactOS for a free, non-criminal, non-r1aa/m9aa/gay-oriented operating system.

Linux trolls refrain from posting, I already know Linux exists and it's so free and all. (And if being an advanved Linux user I'm looking for a free Windows-compatible OS, it must be because Linux isn't/doesn't do what I want, even games aside.)

>>2
No loophole; you can make such a thing. You're not copying Windows but writing your own OS, and you're not copying applications, just they may run. (ReactOS' own console, tools, desktop, and file manager are provided, together with GCC and other free software; then you can install and run Windows drivers and stuff you legally own. Drivers are free.)

You can't reverse engineer Windows however. ReactOS doesn't plain out copy the Windows microkernel and architecture; in fact it uses its own, but it implements a fully compatible interface.

Driver interface and the Win32 API is documented in MSDN, so they know what do do. Of course, there are a few undocumented features here and there, especially old stuff, and I suppose a few internals that need to be done and are not documented. Let's suppose the ReactOS have great divination powers and an outstanding intelligence to do them, and Billy doesn't have enough proof to call that reverse engineering. Considering Microsoft says Windows is documented and with documented Windows you can do it, they can't accuse ReactOS of reverse engineering without admiting there's something to reverse engineer, which would get them in trial again (they lost a cause of undocumented behaviours IIRC), so it's kinda safe.