This paper describes the technical challenges and the application of advanced control methodologies to meet the challenges in the design of servo systems for data storage devices such as hard disk drives (HDDs). Though an emphasis is on control applications to hard disk drives, the challenges and methodologies are broadly applicable to other precision machines. "Mechatronics" in the title emphasizes that the design of control algorithms for modern machines is not an isolated activity by control engineers in the development of products, which is indeed a synergistic integration of mechanical hardware design, sensor and actuator selections and control algorithms.