| Not a misconception at all. Mac OS X was essentially a continuation of NeXTSTEP, which is BSD with a new novel kernel. In fact, if you look into the research history of the Mach kernel at the core of XNU, it was intended as a novel kernel _for_ BSD. NeXT went and hired one of the key people behind Mach (Avie Tevanian), and he became one of the core systems guy that designed NeXTSTEP as a full OS around Mach. Early in the proliferation of the Unix family, member systems went in one of two directions -- they based their OS on upstream AT&T Unix, or they based it on Berkley's BSD, and added their own features on top. NeXT was one of the latter. Famously, the original SunOS also was. While Sun would eventually work closely with AT&T to unify their codebase with upstream, NeXT made no such change. NeXTSTEP stayed BSD-based. The other extant BSDs like FreeBSD and NetBSD were also based directly on the original BSD code, through 386BSD. If I have my history correct, Apple would later bring in code improvements from both NetBSD and FreeBSD, including some kernel code, and newer parts of the FreeBSD userland, to replace their older NeXT userland which was based on now-outdated 4.3BSD code. I think this is where the confusion comes in. People assume MacOS is a only "technically" a Unix by way of having borrowed some code from NetBSD and FreeBSD. They don't realize that it's fully and truly a BSD and Unix by way of having been built from NeXT and tracing its lineage directly through the original Berkeley Software Distribution. That code they borrowed was replacing older code, also BSD-derived. |