You are spot on, Linux is just another Unix derivative. There were ports of Unix for PC architecture long before Linux, FreeBSD, Solaris, and going waaaay back, Xenix (if you are old enough to remember, Microsoft licensed it from AT&T (who developed one major strain of Unix) and it was available on amongst others, the Tandy TRS-80. Damn, I wanted one of those soo much when I was a kid, but they were well out of my price bracket!) The only thing different about Linux, was that it was given away freely. Of course, in business, you end up spending out for software support anyway, so nothing is 'free' in reality.