Andrew Tanenbaum presents a new edition of his worldwide bestseller, essential for understanding the functioning of modern operating systems. It differs significantly from the previous one and includes information about the latest achievements in the field of information technology. For example, the chapter on Windows Vista has now been replaced by a detailed look at Windows 8.1 as the most current version at the time of writing. A large section dedicated to the Android operating system has appeared. Material regarding Unix and Linux, as well as RAID systems, has been updated. Much more attention has been paid to multi-core and multi-core systems, which have been growing in importance over the past few years. There is a whole new chapter on virtualization and cloud computing. A large amount of new material has been added about the use of code errors, malware and appropriate protection measures. The book provides many important details in a clear and engaging manner that are not found in any other publication.