The Hard Drive Turns 50
Fast Forward: 50 Years Later
The disk drive has come amazingly far since its introduction: "Today, on 2.5-inch platters we have 15,000 times the capacity of the original IBM RAMAC," says Seagate Technology Chief Operating Officer Dave Wickersham.
Wickersham notes that the advancement is startling when compared to the pace of other industries: "In the auto industry, to keep that same pace, they'd have gone from fitting five people in the car in 1956, to fitting 160,000 people in that car; or, from getting 25 miles per gallon to 62,500 miles per gallon."
Today we have drives that cover a range of sizes (the smallest is Toshiba's 0.85-inch drive, initially introduced in 2GB and 4GB capacities) and specialties. Vendors offer drives optimized for uses in servers, desktops, notebooks, digital video recorders, music players, and more; and you'll find hard drives in cars, planes, and a wealth of other commercial and military applications.
Prices have dropped dramatically. The RAMAC 305 system's cost per megabyte was approximately $10,000--that's about $70,000 in today's value. Today, a typical desktop hard drive can deliver that same megabyte for 3/100 of a cent.
Over time, the core recording technology--longitudinal magnetic recording--has remained the same, but the way drives are designed and built has changed. Coughlin reflects: "Heads have gone from the original metal cores, to harder ferrite cores, then to thin-film inductive heads; magneto-resistive heads; and then giant magneto-resistive heads. Now we're moving to tunneling magneto-resistive heads. They're now using complex nanotechnologies in magnetic recording heads."
The media has changed, too. "In the beginning, they used iron-oxide particles dispersed in a plastic binder; then they transitioned in the early eighties to the development of the initial thin-film disks," continues Coughlin. "By the nineties, thin film disks were the standard, and since then they've become more complex, with multiple layers of thin films performing different functions. At the same time, the heads are flying increasingly closer to the disk's surface," he explains. The closer the heads fly to the surface, the more data can be stored in a given area--and the drives have become quicker and more accurate. "Increasing electronic integration over the years has led to impressive improvements in head positioning in the detection and decoding of very small signals, and in the correction of errors," he says.
After 50 years of relying on longitudinal magnetic recording, the industry is shifting production to perpendicular magnetic recording. (For details on these technologies, read "How It Works: Hard Drives.") The technology was initially explored decades ago, but is only now being used in drive production. Toshiba was the first out the gate in 2005, with its 1.8-inch 40GB mobile hard drive. Seagate was next to the party, with the release of the first 2.5-inch 160GB notebook hard drive and the 3.5-inch 750GB hard drive earlier this year.
Wickersham elaborates: "From an areal density perspective, perpendicular has changed the industry. For a while, areal density was growing at north of 100 percent per year. Then that came down to 10 to 20 percent a year--demonstrating that longitudinal was out of gas. Perpendicular got us back to this 40 percent per year areal density growth; with it, you can quadruple your capacity every four years."
In our storage-hungry universe of digital downloads and digital photography, increased capacity is a good thing. "There's up to 60 percent per year growth in storage demand, for the next five years," continues Wickersham. "The demand for storage is greater than the ability to grow areal density," he says.