No one is so foolish as to make what can be acquired cheaply or free; it's wiser to pick one from among hundreds of platforms and modules that fill in the holes between open source Unix and your applications.

In contrast, Windows fills in all the blocks between the hardware and your apps. It does it in ways that you can't alter, but which you can use in different ways. You can code with the tools of your choice and in the programming language of your choice, and unless you stray too far from the rule book, everything you create will interoperate with everything others write for Windows. An operating system is a rack into which device drivers and APIs are inserted. A platform is a rack into which applications are inserted.

Linux and Windows don't compete. Sun Microsystems (Profile, Products, Articles) sees this as an opportunity and has struggled mightily to position the combination of Solaris and Java as a platform. It almost makes it. I'd choose J2EE and Solaris over Linux for nonuser-facing server applications in shops that have expert administrators. But, similar to Linux and other flavors of Unix, Solaris is a nonstarter on clients, and that's enough to hurt its capability of competing with Windows. There is only one platform that can stand toe-to-toe with Windows, and that's the combination of OS X and Java.