Took this class at MIT. 20/10 would recommend, especially for people who don't come from a systems background. The textbook is quite easy to understand and the labs are a very good check of your comprehension. Just maybe skip the network driver on the first go around :P

I also took the class that uses this OS at MIT. Absolutely fantastic. I was just browsing the class website today actually, and you can totally kinda take the class yourself. The site has all the lecture notes, the labs, and even a version of xv6 in a repo with branches for all the labs, along with instructions for getting it all working yourself. It's kinda amazing how open it is.

The first lab: https://pdos.csail.mit.edu/6.1810/2023/labs/util.html

I do plan to work through the whole thing myself again at some point soon.

Many of the projects in my OS class in college involved building on top of the xv6 operating system. I remember one of the projects was building a scheduler for xv. It was definitely a great way to learn about different pieces of an operating system!

Plan9 was/is used at a university is Spain for teaching

Ha, on first read of the title I thought this might be a new release of the venerable xv image viewer - http://www.trilon.com/xv/

I have ways wanted to understand the Windows NT kernel -- maybe the earlier versions as they are simpler.

I heard the first version is close to VMS. Is it true? Is there any material on VMS? OpenVMS is open sourced but the version is too high.

Why Unix v6? Why teach with a 50 years old design? I feel to teach the fundamentals of an operating system, i.e. scheduling, IPC, address space management, a microkernel design would be better.

What's a good way for autodidacts to fiddle through this?

Plan 9 is also a pretty simple codebase to understand.

I used PintOS in my operating systems class last semester - wish there was a part 2 to that class where we go even more in depth!

XINU is another simple teaching system.