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What Linux or Unix version underlies Mac OS, OS X 10.6? Is there a good documentation for that version, specifically regarding security, networks and similar topics?

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up vote 5 down vote accepted

Darwin is at the core of Mac OS X. There is documentation of it scattered all over the net, but I've yet to find a good central location that has it all.

A good starting point is Apple's Open Source pages.

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Thank you very much! – usersuper Dec 18 '10 at 19:07

Mac OS is mainly based on FreeBSD. But of course, there is a considerable amount of proprietary code base on top of it. Especially the kernel, besides the user-land, has been heavily modified.

As for documentation, you can check these two books: Mac OS X Security and OS X for Hackers at Heart

I haven't personally read these books, but I was told they were OK.

PS: The TCP/IP stack is one of the areas that have been modified to a lesser extent. The changes are mostly in the data link interfaces, so Mac OS practically inherits a lot from FreeBSD on the TCP/IP stack.

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FreeBSD is just a small part of it, the Kernel is a MACH-kernel unrelated to FreeBSD. Aqua, quartz and all that are custom stuff. – johannes Dec 18 '10 at 18:49

MacOS X uses Apple's Darwin system as a base. Darwin uses parts of FreeBSD but massively diverged in many areas so you can't really give version numbers or such.

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