Comment by qianli_cs

Notice a bunch of downvotes -- Apologies for being unfamiliar with the rules here (I've always been reading HN, but I'm new to commenting). I should've added a lot more details to my previous comment and been more specific. Any other guides would be helpful too. I'll be careful in the future.

When I learned OS, I followed MIT 6.828 (https://pdos.csail.mit.edu/6.828/2017/overview.html) and implemented a small OS called JOS based on Xv6. So if you're looking for some teaching OS in x86, check it out.