New heights for hard disk drives

To this day, hard disk drives (HDDs) remain the only archival mass data storage device in a computer. The first disk drive, called RAMAC (random access method of accounting and control), was developed for the IBM 350 computer in 19571. Over the past decade, as the demands for digital data have exploded, the storage capacity of HDDs has grown at a matching rate, if not faster. Today, a 3.5” HDD has a capacity of 160 GB, capable of storing nearly a thousand times more data than a HDD of the same size just ten years ago. The area storage density of a disk surface in a RAMAC was only 2 kbit/in2. It is now 60 Gbit/in2, a 30 million-fold increase over the past 46 years with an average annual growth rate of nearly 80% during the last ten years. Recent demonstrations have shown area recording densities2 as high as 150 Gbit/in2.