Before we ring out the year, let us together celebrate the golden jubilee anniversary of the hard disk. Back in 1956, IBM designers were working on replacing tape with a storage medium enabling random access to data. Their work led to the building of a device called Random Access Method of Accounting and Control (RAMAC). The HDD era began when RAMAC 305 entered the market in September 1956. The RAMAC could hold 5MB, weighed about a ton, and was five to six feet in length and breadth.
Till the mid-1970s, HDDs were largely used in the enterprise environment. However, they dramatically influenced the direction of all product designs. With HDDs becoming smaller and cheaper, and their capacity increasing tremendously, they paved the way for the advent of PCs and handheld devices.
HDD COVER WIDE RANGE This evolution goes on. Today HDDs are available in a wide range of sizes for a wide range of applications with a wide range of specialties. At the time of this writing, the smallest one is Toshiba’s 0.85-inch drive, available in 2GB and 4GB capacities. All through HDD evolution, the core recording technology was longitudinal magnetic recording, though the way HDDs were designed and built kept on changing. Heads changed from metal core to ferrite core to thinfilm inductive magneto-resistive; while media, from iron-oxide particles to thin-film disks to multiple-layer thin films, and so on. Designers brought about increasing integration among various HDD elements leading to improved head positioning and data capture.
However, the greatest change in HDD evolution came about this year, with design and production shifting from horizontal to perpendicular magnetic recording (PMR), after Toshiba came out with the first such product in 2005.
What does this mean to the product designer? The demand for storage has always been outstripping areal density growth. Since HDD invention, areal density has generally grown at 100 percent per year. But the last few years saw this growth fall below 20 percent, signifying that the technology is on its last leg.
The storage volume required for huge digital downloads and photography calls for superior areal density growth more than that provided by longitudinal. Seagate estimates that for the next five years there will be 60 percent per year growth in storage demand. PMR will provide this. Product designers have new opportunities to design high-capacity HDD-based products—digital audio players, STB video recorders, cellphones, and a range of products for digital lifestyle in a digital home. The cost per gigabyte will keep on falling. Gartner estimates that by 2006 end 80GB to 160GB 3.5-inch drives will cost less than $50. By 2010, this price should fetch 750GB to 1TB drives.
PATTERNED MEDIA Hitachi GST has recently achieved in laboratory 345Gbits/ sq.in. using PMR, which would result in 2TB 3.5-inch desktop drive, 400GB 2.5-inch notebook drive, or 200GB 1.8-inch drive. HDD designers will shortly face another major obstacle: magnetic grains that store data are becoming smaller, and will become so small as to be thermally unstable at room temperature. Patterned media and thermally-assisted recording are possible solutions that Hitachi anticipates would keep HDD advancing for the next two decades. With patterned media, designers create magnetic islands with one magnetic grain representing one data bit, as against current technology using 100 magnetic grains to make up one data bit. In thermally-assisted recording, rather than using fewer grains to represent data, the technology allows magnetic grains to be smaller while resisting thermal fluctuations at room temperatures. A laser beam heats up the media while the magnetic head is writing the data.
While celebrating HDD’s golden anniversary in 2006, I hope HDD heritage will not only enable but also define capacity and performance of products. Happy golden anniversary, HDD! I await your diamond anniversary.
