Originating Author: Fred Moore
Disk storage continues to contain the vast majority of the world’s mission-critical, high-performance, high-availability data. Overall shipments for disk storage in 2006 grew over 40 percent and projections for the next few years expect data growth to remain in the 30 to 50 percent range. Disk diameters have shrunk to a 0.85-inch design, fueling a greater trend to mobile storage appliances. One-inch diameter drives now contain 8+ gigabytes on a single platter and 750-gigabyte disk drives have been announced. The capacity of a single disk drive has grown to 150,000 times greater than the first 24-inch diameter, 50 platter and 5-megabyte capacity RAMAC disk drive in 1956. The usage of low-cost disks using SATA continues to move from the desktop into the data center, creating several new and appealing growth opportunities. Native drive capacities are expected to exceed 1,000 gigabytes or 1 terabyte inside the next three years. The early signs of the super-paramagnetic effect have made each disk supplier begin vertical recording initiatives. Disk technology continues to advance at impressive rates and the end of this exciting evolution is nowhere in sight. The growing requirements for disk storage mandate vastly improved storage management capabilities, more virtualization and improved drive utilization, widespread use of data compression, vertical recording, embedded intelligence, optional encryption and self-healing capabilities everywhere.
Magnetic disk drives have advanced 65 million fold in density, since their introduction in 1956. Along the way there have been numerous innovations. Most of these changes occurred one at a time and generally affected only one component in the drive. Currently, however, the industry is in the midst of a change from longitudinal to perpendicular recording, which requires changes to almost all components of the disk drive recording system: heads, media, channels, servos and head-disk interface. This change is being forced by the fact that longitudinal recording is rapidly approaching the super-paramagnetic limit; however, perpendicular recording is seen as providing only a factor of 5-7 in areal density, before it, too, hits the super-paramagnetic limit. To go further, new technologies are needed. Currently two approaches are being pursued: heat assisted magnetic recording (HAMR) and bit patterned media (BPM) recording. Ultimately, by combining these technologies, a density of 50-100 Tbpsi could theoretically be achieved. In this talk, the author will first discuss the history of the disk drive, point out some of the challenges of perpendicular recording and then discuss the status and future prospects for HAMR and BPM technologies.
