The reorientation of hard drives has begun: The first drives to use perpendicular magnetic recording (PMR) technology to pack more data into less space are out. And our tests reveal that they not only boost storage capacity but perform faster as well.
In tests of the Seagate Momentus 5400.3 and its non-PMR 5400.2 predecessor, the PMR unit showed a modest boost overall, completing its runs in about 7% less time; results just for sustained throughput were even more impressive with a 15% to 17% gain. The PMR drive's greater areal density has little effect on seek speed, a component of many of our tests, but helped when our tasks focused on sustained throughput with sizable files.
PMR aligns the magnetic markers on a hard-disk surface in a different way to increase areal density so you can store more data on every platter. Existing technology was approaching its areal density limits, and drive manufacturers spent several years working to overcome the problem. The result for you is more and cheaper room for your data, which is no small concern in a world moving to high-definition media.
Seagate predicts that relatively soon PMR technology will deliver at least a fourfold increase in capacity. That means 2TB, 3.5-in. single-platter disks for desktops; 1TB, 2.5-in. disks for laptops; and even 50GB for tiny 1-in. drives in MP3 players in the near future.
Headroom for tomorrow is good, but how much do you gain today? The highest-capacity (500GB), 3.5-in. drives currently on the market have an areal density of 125 gigabits per square inch; the PMR Toshiba models and the Momentus 5400.3 have 133Gb per square inch. That's a measurable, if marginal gain, but compared with the average drive's approximately 100Gb per square inch, it's a significant improvement.
With a winning combination of more storage and greater speed, the new drives should be a welcome addition to your storage arsenal. And they cost about the same $2 per GB as current drives -- you'll find the 160GB Seagate drive kit for $320 (list).
While nature allows us to scale down the size of each bit of information, it does not allow scaling to happen forever.
Today, as the magnetic particles that make up recorded data on a hard disk drive become ever smaller, we are approaching a point where the data bearing particles are so small that random atomic level vibrations present in all materials at room temperature can cause the bits to spontaneously flip their magnetic orientation, effectively erasing the recorded data. Magnetic recording scientists and engineers have calculated that this so called "superparamagnetic effect" may become a serious technology issue for new products in only two or three years.
"We want to make sure that as we approach this superparamagnetic effect, Seagate is prepared and has the ability to circumvent it; either go around, over under or through it. Maybe trick it by moving to a different recording technology," Tom Porter, CTO, said.