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

QueeenZ wrote:
And i know that there are not file extensions in Unix but i know there is in Mac OS.. hmm.. don't get that.. 😀 Because as we all know Bill Gates invented them..

Are you really a unix user? Extensions in unix were around before Bill Gates existed.
Do you have a real question?

Unix does not use file extensions. To say that there are none is a stretch. Certain programs have always used extensions to distinguish various files -- like the C-compilers using .c and .h. But to the system, the extension is just part of the file name with no special significance. Mac OS X applications and services can optionally use extensions to identify file types. There is nothing mysterious about that. To Unix, still, it is just part of the file name.

Some of Mac OS X's assignment of extensions is more for making things obvious what they are. .app applications are really package applications that contain bundled files in a single file. Extensions themselves can be added to files or not, depending on whom you are communicating with. There is a Unix board for discussing Unix attributes of Mac OS X:

http://discussions.apple.com/forum.jspa?forumID=735

And http://www.sourceforge.net/ discusses many open source solutions for Mac OS X that are portable applicatiosn across Unix operating systems.

Start with
http://developer.apple.com/documentation/MacOSX/Conceptual/BPFileSystem/BPFileSy stem.html
http://developer.apple.com/documentation/MacOSX/Conceptual/BPFileSystem/Articles /Domains.html and
http://developer.apple.com/documentation/Performance/Conceptual/FileSystem/FileS ystem.html
All will be revealed.

And i know that there are not file extensions in Unix but i know there is in Mac OS.

Of course there are file extensions in Unix. ,h files, .c files, ...

Mac OS X is Unix based. 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. See these articles:
http://en.wikipedia.org/wiki/Macosx
http://en.wikipedia.org/wiki/OS-9

Mac OS X 10.5 for Intel-based Macs has received UNIX 03 certification so it's about as UNIX as things get nowadays. (10.5 on PPC systems should also pass were Apple to apply for certification, but doubtless they just aren't interested in going to the expense and effort for a discontinued platform).

QueeenZ wrote:
well i figured this out when i tried to go to /usr directory which is knows unix systems dir.. but it's hidden in Mac OS as i see.. 🙂

No, it's not really hidden, it's only hidden in the GUI.
Open a terminal and you will see a complete Unix OS, with Apache servers, PHP, Perl, Python, C, Cpp, AWK, multiple shells, and whatever.
If you are at home in a Unix environment, you will be at home in a terminal.

QueeenZ wrote:
well i figured this out when i tried to go to /usr directory which is knows unix systems dir.. but it's hidden in Mac OS as i see.. 🙂

"Go" menu --> "Go to Folder" --> /usr

Jeffrey Jones2 wrote:
Unix does not use file extensions. To say that there are none is a stretch.

I would say that Unix does not need file extensions but it has them in many cases.
In the PC world (and maybe elsewhere), extensions are the scorecards that let you tell the players apart 🙂

In Unix the extensions are a convenient way for humans to know what the file is or does, so when opening a file, one has an idea what tool to use. When 'lessing' a binary file for instance, a warning pops up about the file being binary.
And conversely, in Unix, any file can be run, even a nonsense text file, with sometimes curious results, but the extensions are handy, especially for humans.
Since everything is a file in Unix, so to speak, a directory can have a .txt extension if one so desires.

We are also drifting miles away from the OP's subject, which has been answered several times:
Yes, Leopard is a *nix-based OS.

Message was edited by: nerowolfe

Mac OS X is based on the Mach micro kernel and BSD 4.4 (and FreeBSD 5 and onwards for the newest versions, although code from NetBSD has made its way into the BSD subsystem too) and is to be considered a version of Unix. It doesn't sport a typical monolithic kernel like Unix usually does, but as mentioned earlier its kernel is rather a hybrid between two architectures.

Because of the BSD underpinnings, and often relatively simple recompiling efforts, Mac OS X is capable of running a significant number of traditional Unix and open source applications as well as Mac OS X applications. Simultaneously.

Mac OS 9, on the other hand, has no Unix heritage and is not to be mistaken for the real time Unix like operating system, that is OS-9. The makers of OS-9, Microware Systems Corporation, even sued Apple over the name 'OS 9', seemingly thinking that people would mistakenly associate the two products with another.

Mac OS 9 was a cooperatively multitasking, multithreaded single user system, whereas Mac OS X is a multithreaded, multitasking multi user system.

As mentioned by others, Mac OS X 10.5 is certified Unix.

That must mean that there's root user somewhere 🙂 Right? 🙂

There is indeed: please see
http://www.macosxhints.com/article.php?story=20071025100950309
and
http://www.macobserver.com/tip/2008/06/13.1.shtml

As you are Unix experienced you will be aware that you can do immense amounts of damage as root.

Yes, user ID 0 is root on OS X, just like any other UNIX. And, like many modern Linux distributions, root doesn't have a login by default. You simply cannot login as root, rather you must be logged in as another user, and from there you can use various means to do things "as root" by requesting the privilege.

You can "enable" the root account on a Mac by creating a password for the root account, but there's really nothing for which that's necessary.

QueeenZ wrote:
well it's BSD Unix based OS as far as i know. but Bill did invent DOS 8.3 and 16.3 - file extensions..

No, he did not. In fact he "borrowed" his OS from QDOS.
And even QDOS was based on or "borrowed" from CP/M

And in CP/M, which dates back to the early 1970's, we find the following:
File system
File names consisted of up to 8 characters, a period, then up to three characters as a file name extension (8.3 filename convention).
Bill Gates was a salesman and promoter. He did not invent any OS.

And in truth, Apple also borrowed much from Xerox PARC as did Gates. But that's something else entirely.

That must mean that there's root user somewhere 🙂 Right? 🙂

That not a logical assumption. You are improperly drawing an inference. It does not follow that anything Gates did implies a root user in Leopard. They are completely separate items.
Leopard having a root account has nothing at all to do with Mr. Bill.

Message was edited by: nerowolfe

Dave Sawyer quoting nerowolfe wrote:
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.

Which is precisely why I put the word borrowed in quotes.

As I recall, Gates "borrowed" QDOS and led IBM to believe he owned exclusive rights to it. He bought it later after IBM agreed to use it. I believe Gates did not buy exclusive rights to it, but I may be wrong. In any case, Gates did not write DOS. I am not sure Gates is or was ever a programmer.

In the end, SCM was awarded 1 Million dollars for QDOS, as ported to IBM's boxes. SCM was exonerated, and IBM realized from where the OS actually came.

And then Gary Kildall, of DR, who created CP/M, noticed (as did may early users of PC-DOS) that some of the code looked very familiar. Lo! and Behold, much of DOS (PC and MS) was heavily "borrowed" from CP/M. BASIC was also from the mind of Gary - actually one of his students.

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

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