<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Mon, Oct 5, 2015 at 6:42 PM, Dave Horsfall <span dir="ltr"><<a href="mailto:dave@horsfall.org" target="_blank">dave@horsfall.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">On Sat, 3 Oct 2015, Ryan Schmidt wrote:<br>
> > Remember: under the bonnet (ObUSA: hood) the Mac runs FreeBSD.<br>
><br>
> OS X is underpinned by Darwin, not FreeBSD. Darwin is based on NeXTSTEP,<br>
> BSD, XNU and other projects, and of course a great deal of independent<br>
> work by Apple.<br>
<br>
</span>You're saying that Darwin was written from scratch and not evolved from a<br>
modified FreeBSD 4.1, or am I thinking of an earlier MacOS?<br></blockquote></div><div class="gmail_extra"><br></div>It was never derived from FreeBSD 4.1.</div><div class="gmail_extra"><br></div><div class="gmail_extra">CMU Mach was a custom-written microkernel, hosting an OS which was a heavily modified 4.2BSD (the original Berkeley Source Distribution, long predating FreeBSD). NeXTStep took this and updated it. OS X took that and updated it again, including replacing much of the userspace that was not Darwin-specific with FreeBSD-CURRENT as of that time, and periodically updates those parts of the userspace from the latest FreeBSD-CURRENT. The kernel, however, is still largely custom. Some subsystems were originally borrowed from FreeBSD-CURRENT (the original USB stack, for example), but Apple later rewrote them (and in the case of USB, that was badly needed; FreeBSD still has significant USB stack issues). The core of the kernel is not, however, related to FreeBSD except in being a heavily rewritten version of FreeBSD's ancestor.<br>-- <br><div class="gmail_signature"><div dir="ltr"><div>brandon s allbery kf8nh sine nomine associates</div><div><a href="mailto:allbery.b@gmail.com" target="_blank">allbery.b@gmail.com</a> <a href="mailto:ballbery@sinenomine.net" target="_blank">ballbery@sinenomine.net</a></div><div>unix, openafs, kerberos, infrastructure, xmonad <a href="http://sinenomine.net" target="_blank">http://sinenomine.net</a></div></div></div>
</div></div>