What's the line you're drawing between an OS and a distribution? I certainly would have said that these various different Linux distributions you reference wer

What's the line you're drawing between an OS and a distribution? I certainly would have said that these various different Linux distributions you reference were different distributions of the same Operating System. Which is the same thing with OS development at Microsoft. Microsoft builds one Operating System (Windows) and bundles it into different distributions (Xbox, Windows Mobile, Windows Server, etc). In the old business model, you could have had kernel hackers throughout the company that didn't talk to each other. The Windows team would build an operating system and then other teams would adapt it - for example, Windows Server was part of Server and Tools Business, not the Windows division. It only makes sense to bring everybody under the same roof.