Unix is a specification. Mac OS X is a certified implementation of Unix. This like asking "What is the difference between a turtle and a red-eared slider."
Mac OS X is based on UNIX.
Windows, Unix, Mac OS
Mac-OS=Disk operating system==Linux OS==Windows OS==Unix OS=
The reason for the exec functions being same/similar is because the Mac OS has its roots in variants of the Unix kernel.
No difference, really. Unix is an OS (Operating System)
Yes Mac OS is based on Linux
Mac OS X is pronounced Mac OS Ten. It follows on from Mac OS 9 which was the last version of what is now known as the classic Mac OS and it saw the introduction of the new UNIX based OS so the Roman numeral X was adopted to mark the change.
Mac OS X is an operating system running a UNIX shell, unlike Windows which uses a DOS shell. Most software must be specifically designed for use on Mac OS X because of its different shell, though UNIX provides Mac with improved security.
Dos Unix Linux Windows Mac OS OS/2
Solaris, Mac OS X, HP-UX, and IRIX are all examples of Unix systems.
No, the Registry is a feature of Microsoft Windows only. Neither the original Mac OS or the newer Mac OS X have ever used a Registry, Mac OS X is based on Unix which has never used a Registry.
Mac-OS=Disk operating system==Linux OS==Windows OS==Unix OS=