IO structure

Yikes, this is a huge question. I suggest you pickup a book by O'Reilly called The Linux Kernel.

Linux and BSD have similar I/O, but XP is different because of the setup with the Executive and Kernel.

Actually, the full title of the O'Reilly book in question is "Understanding The Linux Kernel". I have it on a shelf near at hand. jmgarvin is right: OS I/O systems are not something to explain in brief in a short paragraph or two. The book is great for giving an in-depth theoretical understanding of Linux kernel architecture.

Because of the Microsoft philosophy of obfuscation, it's not so easy to get your hands on similar information for Windows. You'll have to kina pick it up as you go, or start reading some serious Windows programming references. It's similarly difficult to get that sort of overview of the differences between BSD I/O from how Linux does it, though only because there aren't many books (yet?) about BSD kernel architecture and programming.

"Understanding The Linux Kernel" does touch on differences between Linux and other OSes, including other unices (like *BSD and Windows), though that's not the main thrust of the text.