i read this article about a month ago and it actually really irritated me. not necessarily because i just switched from linux to a mac, well, actually i really just added a mac to my collection, but something about it bothered me. i even spoke to a few people about it one of which is hands down the most knowledgable computer geek i know. the main thing that irritated me about the article is that it didn't even mention the operating system!! the entire basis of the article was founded on external applications. on top of that it's gnu software!!!! there was no mention of that little thing called a kernel, no mention of any subsystems and the configuration facilities, what does that have to do with anything?!?!? if wrote a clone of the windows registery and threw it on your linux box would it then be windows or at least cease to exist as a *nix?
after a long time of thinking about it and talking with people about it became very apparent that even people that pride themselves on being unix junkies can't sufficiently explain exactly what makes a unix operating system a unix operating system. if you take two unix guys junkies that don't know eachother, put them in different rooms and ask them what makes an operating system a unix operating system you'll get very different answers. try to take the common denominator from their responses and after you go through a few more people that becomes thinner and thinner until it vanishes into thin air.
my question basically is what makes an operating system a unix operating system? the kernel? is the mach microkernel a unix kernel? if so the windows operating system has been using a mach based kernel since windows 2000 came out. would that make it a unix based operating system?
my point? the unix operating system has had a monumental impact on the computing world and on the design and implementation of every operating system i've even seen. it has enompassed so much of the computing world that it's difficult to even distinguish between what is unix and what is unix because almost every os vendor has borrowed, or tried to borrow, so much of the unix operating system.
my last question to the author is, so what if os x isn't unix? the linux operating system is also unix-based, as you pretty much said yourself. go out and pick up a mac, if you can't get just about any of the applications you would run on a unix box to run on your os x box then you probably don't even know how to use that unix, or linux box well enough to tell the difference between unix and os x. so either way you'll be happy!!