We used this for my Computer Architecture class in college and it's one of the few textbooks that I wish I had kept around. I had a used copy so not selling/returning it to the bookstore really wouldn't have been too impactful at the time. Now that I'm wanting to get back into low-level programming, I miss it even more.

Is there a book or resource you'd recommend for operating systems? I recently finished CS:APP and really enjoyed it. Though I've been programming for ~7 years and felt that made it easier to digest.

Going through this now and it's great

+1. This book changed my life. Wouldn't be doing what I'm doing today without it!