Is Mac OS X Unix-Based Operating System..?

Well, "borrowed" to some would imply just taking the features, etc. without compensation (as QDOS did with CP/M), whereas Gates actually purchased the OS.

I believe Gates did not buy exclusive rights to it,

Nope, he did. He first purchased nonexclusive distribution rights for $25,000, then came back and bought exclusive rights for an additional $50,000. After a later legal threat by Seattle Computer when they learned about the pre-existing deal with IBM, Microsoft paid an additional $1M.

'nuff said on the subject. Now we return you to our regularly scheduled programming. 😉

I agree its a rather pointless distinction to try make.

It has been a custom for a very long time, but its not obligatory to the system itself (as J. Jones says).

The shells, RE engines, software libraries, etc., have "built-in" ways of picking out filename extensions, but that's higher-level conventions: the user isn't actually obligated to add an extension for the sake of Unix itself.

a brody wrote:
...Some would argue it isn't Unix because it is more based on BSD Unix, and the Mach kernel. System 1 through 9.2.2 have less of a Unix base, but still having some.

A pretty good place to clarify your understanding of what constitutes UNIX in the present day is simply to be found at unixdotorg . Leopard is, as stated, UNIX 03 certified, so I wouldn't confuse yourself by comparison to BSD Unix which is actually different from OS X.

http://www.opengroup.org/platform/unix_certification/news.tpl?CALLER=public.tpl& gnid=548

nerowolfe wrote:
I guess this goes all the way back to Ada Lovelace, presumably the world's first computer programmer, and Babbage. Most likely even earlier.

I'm not certain I'd count external physical media such as punch cards in this digressions into ancient computing history.

nerowolfe wrote:
Getting back to the subject of this thread, indirectly, the original Unix OS had to have been written in some language and run on some computer that did not run on Unix. Once, most people programmed in assembler and before that machine code. As noted, many early programs and OSs were written by stringing wires through ferrite beads.
Message was edited by: nerowolfe

It was originally written on DEC PDP-7 in assembly, so I guess object code.

Ewen wrote:

nerowolfe wrote:
I guess this goes all the way back to Ada Lovelace, presumably the world's first computer programmer, and Babbage. Most likely even earlier.

I'm not certain I'd count external physical media such as punch cards in this digressions into ancient computing history.

nerowolfe wrote:
Getting back to the subject of this thread, indirectly, the original Unix OS had to have been written in some language and run on some computer that did not run on Unix. Once, most people programmed in assembler and before that machine code. As noted, many early programs and OSs were written by stringing wires through ferrite beads.

It was originally written on DEC PDP-7 in assembly, so I guess object code.

My sardonic comments were just that. My questions were also rhetoric. I have used and programmed PDP 7s, written in and used CP/M and early BASIC. I know the origin of the cryptic "? redo from start" error message.

But the question here has been answered many times.
Yes, Mac OS is a Unix-based OS. The key words are Unix-based. Whether one considers Linux, BSD or even Coherent a Unix system, they are all certainly Unix-based. If you grep you know. If you make dep you know even more.

Message was edited by: nerowolfe

See http://support.apple.com/kb/HT1528 for details about the root user account.

See if this helps:

http://en.wikipedia.org/wiki/MacOSX

At the risk of prolonging a pointless argument, some Unix users use extensions, some Unix programs use extensions, but they mean nothing at all to the system itself.

No, he did not. In fact he "borrowed" his OS from QDOS.

To be completely accurate, Gates bought the rights to QDOS, aka 86-DOS, from Seattle Computer.

Well, Mac OS X certainly has its roots in UNIX, but remember, nerowoof, that isn't true of Mac OS pre OS X or some of the OSes used in non-Mac Apple products