> Tru64 UNIX and QNX have Micro-kernels, DragonFlyBSD and MacOS Hybrid.
You're reading too much into my comment. The original PDP-7 (and later PDP-11) Unix are monolithic kernels. The most popular Unix variants or clones today (Linux, Free/Net/OpenBSD) are all monolithic kernels.
Tru64 is long dead. QNX has a niche market. DragonFly ... not much market share.
MacOS? As you say, hybrid, not microkernel, and is hardly successful in the same space that the monolithic kernel Unices are (ie. servers).
It's not hard to argue that Unix has historically been a monolithic design, and that those have been the most successful, even if you can certify various microkernels.
Of course this comment may not hold for another 50 years, but it is certainly true of the last 50.
> And its really not my problem if you think a unix has to be mono..thats just wrong and you know it.
It's not really my problem if you think I said UNIX has to be a monolith, since I never said that.
Xv6 is a reimplementation based on the original v6 UNIX design. As a teaching tool for the historical design of UNIX, it's a great place to start. If you want to study Unix-like microkernels, then MINIX and Tanenbaum's books are a great place to start.
If you want to study hybrid Unix-like systems, then the Darwin source code might be a good place to start. MacOS as a popular, hybrid, desktop Unix is pretty much an anomaly in the course of Unix history.
Study whatever you want, but for beginners to OS design, it's easier to understand hybrid and microkernel systems if you first know what a monolithic kernel is, and how various modern versions of Unix evolved from that in my personal opinion.
Nobody really gives a rat's ass about UNIX certification in the real world ... except MacOS fans.
I hear this a lot - but given that consumer choice is pretty much taken out of the equation, I don't really consider popularity to be applicable. People don't buy Intel CPU's because of the Minix ME.
Tru64 UNIX and MacOS are UNIX certified.
>for a start
https://en.wikipedia.org/wiki/Unix
Varies; monolithic, microkernel, hybrid