What is the future of disk drives, death or rebirth?

Disk drives have experienced dramatic development to meet performance requirements since the IBM 1301 disk drive was announced in 1961. However, the performance gap between memory and disk drives has widened to 6 orders of magnitude and continues to widen by about 50 per year. Furthermore, energy efficiency has become one of the most important challenges in designing disk drive storage systems. The architectural design of disk drives has reached a turning point which should allow their performance to advance further, while still maintaining high reliability and energy efficiency. This article explains how disk drives have evolved over five decades to meet challenging customer demands. First of all, it briefly introduces the development of disk drives, and deconstructs disk performance and power consumption. Secondly, it describes the design constraints and challenges that traditional disk drives are facing. Thirdly, it presents some innovative disk drive architectures discussed in the community. Fourthly, it introduces some new storage media types and the impacts they have on the architecture of the traditional disk drives. Finally, it discusses two important evolutions of disk drives: hybrid disk and solid state disk. The article highlights the challenges and opportunities facing these storage devices, and explores how we can expect them to affect storage systems.