Well, Windows also keeps compatibility layers whose only job it is to run legacy code. If a handful of enthusiasts can do a better job on a completely different

Well, Windows also keeps compatibility layers whose only job it is to run legacy code. If a handful of enthusiasts can do a better job on a completely different underlying operating system, they have obvious improvement possibilities. The curse of Linux is that every moving part is its own project. Libc and the gcc C++ API is notoriously problematic with backwards compatibility, so the backwards compatbility of Linux as a whole is also restricted. I just want to question the often-repeated picture of Microsoft as obsessed with backwards compatiblity. Where does that idea come from? I'm just not seeing it at all. A new Windows box will not even authenticate with a too old AD server. If you want examples of backwards compatibility, look at S/360, AS/400, VAXen, pretty much any other operating system with an enterprise prescence.