UNIX for Dummies Questions & Answers

To anyone that has the answer:
What does UNIX have that Mac OSX doesn't. I am a programmer, and I am wondering if I could just get Mac OSX for my programming needs instead of UNIX. But my major question is what does UNIX have that Mac OSX doesn't. Thank you if you have the answer, and are willing to post it!
-REM

Mac OS X (Ten) has been out in production for about 4 months, so Apple says. Here is a link to a post that will have more pointers to Apple pages and Apple analysis:<P>

http://forums.unix.com/showthread.php?threadid=908
<P>

Basically, OS X is a evolutionary kernel from the MACH and BSD linage. According to Apple, they plan to migrate all apps to this kernel, over time. Earlier kernel (OS 9) non-UNIX runs as well, but it is not yet clear to me if the OS9 kernel space is a UNIX process or partitioned closer to the CPU. When I run a PS command in the OSX environment, I do not see any OS9 processes (even when I have OS9 processes on the desktop).

To be honest, I don't have time to fully study this as of yet; but plan to! If someone else has the time to read about OSX, please do so and give us a tech summary, thanks Here is a link to the <A HREF=http://developer.apple.com/macosx/>MAC OS X Developer Site</A><P>

Here is the: <A HREF=http://www.opensource.apple.com/ps-faq.html>DARWIN and Apple Open Source FAQ</A>. <P>

Also, here is a link to <A HREF=http://developer.apple.com/techpubs/macosx/macosx.html>The Apple OS X Developers Documentation</A> with tons of information.

While I'm completely new to Unix, I've read quite a bit on Mac's new OSX and it's relation to Unix. OSX is an evolutionary modification of the FreeBSD kernel complete with a very fast and fluid GUI using Adobe's Portable Document Format for it's screen preview. Apple calls this propietary modification of FreeBSD "Darwin." Knowing very little about the functionality of Unix and based solely on what I've read, Mac OSX is 100% Unix-based. OSX comes with it's own command-line terminal for programming or accessing core elements of the OS. It also fully supports Java development and ships with one entire disk dedicated to Application Development Tools (primarily using Java as well as tools to build OSX applications with the Aqua interface. There are two types of apps on OSX, Carbon and Cocoa.