My rating: 5 of 5 stars
Operating Systems Concepts is a great undergraduate-level resource for its subject, focusing, as its name advertises, on the concepts behind building an operating system. Outside of the exercises, the text spends relatively little time on code examples or gritty details, relegating that to suggested reading or simply saying “Go look at an open-source operating system!”.
This emphasis on concepts makes a great deal of sense given the variance in how to accomplish goals and the sheer amount of groundwork which the book needs to cover. The book is already over 900 pages!
This book is a great read for any long-time user of operating systems who wants to understand the amazing piece of software that orchestrates their entire computing experience, as well as being great review for practitioners who want a refresher. Five stars.