Comment Re:ELI5 please (Score 4, Informative) 354
It's a little more complicated than that.
You didnt just write some GPL piece of software for windows, you wrote some GPL software that is so tightly integrated with Windows you actually had to reverse engineer parts of Windows and replace original system files with new ones, composed in part of what we think of as your program, and in part of your reverse-engineered best guess on the original Windows system code. Probably problematic to distributed, if Microsoft had cared, but it was boosting their sales so they didnt raise any fuss. In fact, they turned around and bought out your company instead. Took over operations, but critically did not receive the copyright to this GPL software (which was always, if I am not mistaken, owned by the contributors, not the company.)
This is where it gets tricky. Now THEY are the ones distributing your GPL code linked to their own code, not your reverse-engineered stand-in. I am not 100% sure I am getting that part correct, but it seems to be the case. And if it is the case... then at that point Microsoft would actually be in violation of your license. They would have, as I see it, three options. They could simply quit using your code entirely, which they obviously do not want to do, and which would only prevent continuing violations but still leave them at least theoretically liable for past damages; they could GPL Windows itself, and use your code freely; or they could purchase either copyright or a side-license to continue using the code outside the GPL.
You didnt just write some GPL piece of software for windows, you wrote some GPL software that is so tightly integrated with Windows you actually had to reverse engineer parts of Windows and replace original system files with new ones, composed in part of what we think of as your program, and in part of your reverse-engineered best guess on the original Windows system code. Probably problematic to distributed, if Microsoft had cared, but it was boosting their sales so they didnt raise any fuss. In fact, they turned around and bought out your company instead. Took over operations, but critically did not receive the copyright to this GPL software (which was always, if I am not mistaken, owned by the contributors, not the company.)
This is where it gets tricky. Now THEY are the ones distributing your GPL code linked to their own code, not your reverse-engineered stand-in. I am not 100% sure I am getting that part correct, but it seems to be the case. And if it is the case... then at that point Microsoft would actually be in violation of your license. They would have, as I see it, three options. They could simply quit using your code entirely, which they obviously do not want to do, and which would only prevent continuing violations but still leave them at least theoretically liable for past damages; they could GPL Windows itself, and use your code freely; or they could purchase either copyright or a side-license to continue using the code outside the GPL.