The fall 2013 textbook for COMP755 Advanced Operating Systems is
Operating System Concepts with Java, 8th Edition, by Silberschatz, Galvin and Gagne, Wiley, 2007, ISBN: 9780470509494, ebook: 9780470574324
The book will be available at the A&T bookstore on campus or online with a price of $182.65 new, $137.00 used and $69.50 as an eTextbook.
The book is available from several online book sellers. There are search engines which can assist you in finding the book. Some examples are:
The best price I have found is $120 new or $74 used. If you are purchasing the textbook after the start of the semester, you may wish to pay for expedited shipping.
Textbooks are expensive, but in the bigger picture of your education, they are a useful investment. Not having a textbook may result in your not grasping the concepts as well and therefore not getting as good a grade as you might. If you shop wisely, textbooks need not be a major expense. If you buy a $74 used book now, you might be able to sell it at the end of the semester resulting in a trivial overall expense. (If you can sell the $74 book at a profit, it is better than not buying a book at all.)