For anyone looking to pick up Computer Systems: A Programmer's Perspective, you should probably avoid the Global Edition. From the author's website [0]:
> Note on the Global Edition: Unfortunately, the publisher arranged for the generation of a different set of practice and homework problems in the global edition. The person doing this didn't do a very good job, and so these problems and their solutions have many errors. We have not created an errata for this edition.
If you can't afford the book, it seems like the First North American Edition is available on the Internet Archive, although I'm uncertain of its legality. Remember to support the authors, if not now then hopefully in the future after you get a high paying software engineering job.