Ok, in theorie is Linux niet op UNIX gebaseerd, maar daar is nog lang niet iedereen het mee eens (zie de wiki link naar SCO controversies). OS-X is gebaseerd op BSD, wat weer gebaseerd is op UNIX. (maar nu wellicht geen UNIX code meer gebruikt?).
Hoe dan ook UNIX is de link die zowel Linux als OS-X met dit verhaal verbindt.
Bron: wikipedia
Over OS-X
Mac OS X (pronounced /ˈmæk ˌoʊ ˌɛs ˈtɛn/ mak oh es ten)[6] is a series of
Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, Mac OS X has been included with all new Macintosh computer systems. It is the successor to Mac OS 9, released in 1999, the final release of the "classic" Mac OS, which had been Apple's primary operating system since 1984.
Over Linux
The Linux kernel is an operating system kernel used by the Linux family of
Unix-like operating systems
Over BSD
Berkeley Software Distribution (BSD, sometimes called Berkeley Unix) is a UNIX operating system derivative developed and distributed by the Computer Systems Research Group (CSRG) of the University of California, Berkeley, from 1977 to 1995.
Uit de wiki over Unix-like
Dennis Ritchie, one of the original creators of Unix, has expressed his opinion that Unix-like systems such as Linux are de facto Unix systems.[6] Eric S. Raymond and Rob Langley have suggested[7] that there are three kinds of Unix-like systems:
Genetic UNIX
Those systems with a historical connection to the AT&T codebase. Most (but not all) commercial UNIX systems fall into this category. So do the BSD systems, which are descendants of work done at the University of California, Berkeley in the late 1970s and early 1980s. Some of these systems have no original AT&T code but can still trace their ancestry to AT&T designs.
Trademark or Branded UNIX
These systems—largely commercial in nature—have been determined by the Open Group to meet the Single UNIX Specification and are allowed to carry the UNIX name. Most such systems are commercial derivatives of the System V code base in one form or another, though a few (such as IBM z/OS) earned the trademark through a POSIX compatibility layer and are not otherwise inherently Unix systems. Notably, Apple Mac OS X 10.5 and later is BSD variant, and has been certified. Many ancient UNIX systems no longer meet this definition.
Functional UNIX
Broadly, any Unix-like system that behaves in a manner roughly consistent with the UNIX specification; more specifically, this can refer to systems such as Linux or Minix that behave similarly to a UNIX system but have no genetic or trademark connection to the AT&T code base. Most free/open-source implementations of the UNIX design, whether genetic UNIX or not, fall into the restricted definition of this third category due to the expense of obtaining Open Group certification, which costs thousands of dollars, not being commercially necessary.
en dit plaatje uit deze wiki is wellicht ook interessant:
http://en.wikipedia.org/wiki/File:Unix_history-simple.svg
Hoe dan ook: deze onduidelijkheid is de reden dat Linux en OS-X soms in dit verhaal genoemd worden, terecht of onterecht. Als we naar het plaatje uit bovenstaande lin kijken dan lijkt OS-X in ieder geval verre familie van UNIX, Linux niet. Dit betekent echter niet meteen dat OS-X UNIX code gebruikt die bezit van Novell (het IP althans) was noch dat Linux nergens inbreuk maakt op de patenten van Novell. Dat ligt ingewikkelder en is al vaker reden voor discussie geweest:
http://en.wikipedia.org/wiki/SCO-Linux_controversies