MINIX was also created for teaching. Is there a comparison of Xv6 vs. MINIX pros and cons for teaching?
Xv6 is also written in a more modern coding style, using stuff like C99 initializers. It runs on modern hardware, even supporting SMP.
The performance concerns that famously killed the microkernel hype are very old at this point. Modern hardware significantly reduces IPC overhead. And lots of the modern application stack (e.g. multiprocess browsers) essentially cobble together microkernel primitives out of comparatively-clunky OS features (e.g. cmsg on Unix).
I think most of Linux's success relative to microkernel designs was due to being in the right place at the right time, not due to any fundamental technical factors.
* https://blog.darknedgy.net/technology/2016/01/01/0/ (https://news.ycombinator.com/item?id=10824382)
In case you see this comment 5 days later, can you elaborate? And do the benefits of modern hardware in this area automatically apply to IPC on existing mainstream systems, or does the OS have to specifically use the new support?
They could have said "gravely ill-adopted". You know what they meant and are grinding your personal axe here... Microkernels for all their promise aren't in widespread use. Engineers with a resume headline "I build monolithic kernel operating systems for fun" vs "I build microkernel operating systems for fun" will have significant hiring delta biased towards the monolithic specialists.
Ah, you haven't heard about MINIX, the operating system used in the ME in modern Intel chipsets and possibly now one of the most widely deployed operating systems on the planet.
* https://news.ycombinator.com/item?id=15642116
* https://news.ycombinator.com/item?id=15634014
No, they won't.
What?! Linus, is that you?
In fact, Xv6 was derived from the UNIX v6. You can think of it as an x86 port of UNIX v6.
xv6, on the other hand, is just bare kernel with no functional purpose.