After 50 years, the useful life of the hard disk drive (HDD) is increasingly being threatened by synchronous dynamic RAM and flash-based semiconductor solid state disk (SSD) storage. For example, Samsung Electronics Co. has announced plans to release a 64GB SSD drive in a 2.5-in. design with an integrated drive electronics/Advanced Technology Attachment or Serial ATA interface. And current 32GB flash memory is selling for $1,800 or less. So is SSD ready to surpass HDD in capacity and price? And has the HDD reached the physical limits or can the technology be pushed further? Over its 50-year life span, the HDD has evolved from a 5MB storage device with 50 24-in. disk platters about the size of a household refrigerator to a 1-in. 8GB device found in Apple Computer Inc.'s iPod and other MP3 players. Physically larger than the 1-in. HDDs found in consumer MP3 players and cell phones, 7,200-rpm, 3.5-in. HDDs have capacities of 750GB priced in the $400 to $500 range. Even larger 1TB HDDs are just around the corner. For a good HDD synopsis and history, check out the recent Computerworld piece "From Elvis' hips to spinning disk: 50 years of innovation."
Figure 1 Relative HDD trends and directions
(Click image to see larger view)
To remain viable as a storage technology, HDDs must continue to improve on price, reliability, durability, power consumption, footprint, capacity and performance (see Figure 1). Perpendicular recording technology that is replacing longitudinal recording on HDD, combined with other enhancements, should extend the useful life of the HDD for about another 14 to 15 years, estimate researchers such as Mark Kryder, chief technology officer of Seagate Technology Inc.
At some point before then, a major technology shift or revolution will be required unless a significant breakthrough in physics and material composition among others can extend the HDD even further. What this means is that since it takes about five years for a technology to be fully integrated into an ecosystem like the storage industry, to be available around 2020, we would need to understand what the replacement technology will be sometime around 2015 or so. While 2015 is less than nine years away, that still leaves plenty of time before you will need to unplug your existing storage systems.
Storage technologies or disk systems have traditionally have been replaced on three-to-five-year cycles that should enable users to deploy several more iterations and generations of HDD-based storage before some new technology is defined and developed and products are ready for mission-critical deployment. We should start seeing signs of a new major technology shift in about nine to 10 years. However, between now and then, assume that many smaller (on a relative scale) technology improvements and evolutionary enhancements will continue to appear.