CHAPTER 26 – Case Study

The disk drive selected for the case study discussed in this chapter is the Hitachi Global Storage Technologies Deskstar 7K500. This is a 3.5" form factor drive targeted for desktop machines and entry servers for IT applications, as well as for personal video recorder and gaming applications in the consumer electronics market. All the components of the Deskstar 7K500 are basically of conventional designs. Two new design features not available in previous-generation products are added: Rotational Vibration Safeguard (RVS) and new arm design to reduce flutter. As one of the intended applications of the Deskstar 7K500 is DVR (digital video recorder), acoustics is an important feature. One option for reducing the noise generated by the drive is to reduce the speed of actuator movement. The Deskstar 7K500 has five disks and ten heads. Conventional cylinder mode formatting is used. According to the spec sheet available for the 7K500, there are 25 distinct recording zones. The 7K500 uses adaptive formatting. The 7K500 provides full support of the new Streaming Command Set, which has been adopted as part of the ATA-7 standard. Its purpose is for AV (audiovideo) applications, where on-time delivery of data to maintain a smooth presentation is more important than delivery of data without errors. Results of the Deskstar 7K500 for some of the performance tests are described.