Here's 2 amazing resources to learn Operating systems:

1. Operating Systems: Three Easy Pieces (pages.cs.wisc.edu)
   free • book • by Remzi Arpaci-Dusseau, Andrea Arpaci-Dusseau • 2018

   This book is the best introduction to the world of operating systems. It is centered around three conceptual pieces of an OS: virtualization, concurrency, and persistence. In understanding the conceptual, you'll learn the practical, including how real operating systems schedule CPU, manage memory, and store files persistently. The clear writing, well-thought structure, and exercises make this book a true gem.

2. Modern Operating Systems, 5th edition (www.amazon.com)
   paid • book • by Andrew Tanenbaum, Herbert Bos • 2022

   This book evolved from famous Operating Systems: Design and Implementation, which focused on MINIX and inspired young Linus Torvalds to create Linux. It's the most comprehensive take on the subject that covers all components of a modern OS with relevant examples from Linux and Windows.