Fwd: OS-X

[Justin Dugger]

On 5/16/07, Jonathan Hutchins <hutchins at tarcanfel.org> wrote:
> For a long time, I've been under the impression, largely from friends who have
> been running Macintoshes for ages, that OS-X was based on one of the three
> BSD forks - that essentially it was a *BSD with an Apple window
> manager/desktop environment, and with the kernel (and other programs) locked
> to the Trusted Program Module (TPM).
>
> Comments from some of you lately led me to do some research.  It appears that,
> at least on the internet, current documentation agrees that OS-X is based on
> Openstep, which evolved from NeXTSTEP, which was derived from 4.4 BSD
> (pre-fork?) and the Mach OS.
>
> It's funny how knowledge like this can evolve on the web.  What gets collated,
> analyzed, and archived becomes the truth.  What was known to be true at the
> time gets forgotten.   Mode Emulators become Modulator/Demodulators.  Other
> acronyms drift.

The history of an operating system is not the same as a kernel itself.
 What you have is mostly correct, but misses a critical juncture in
the creation of the OS X kernel.  Mach uses several BSD userspace
tools, but that doesn't make the kernel BSD derived. Recall that for a
long time BSD was a set of software packages that ran on top of
someone else's UNIX kernel.  Mach was the defining implementation of
microkernels.  BSD kernels, like Linux kernels, are monolithic in
nature.

The internet is confused on the difference between an OS and a kernel,
so don't trust the internet.  The end result is that OS X is "Based on
BSD" in a sense, but not a universal "everything should work after
fifteen years of parallel development".  So can get X11 apps to
compile work, but probably not a driver.

Justin Dugger