PMR technology is running out of time – and space – says Seagate's Mark Re, senior vice president of heads and media research and development. It is expected to reach its capacity limit near 1 terabit per square inch in the next few years, and given the insatiable demand for more and faster storage, a replacement technology was required. HAMR offers a theoretical areal density limit ranging from 5 to 10 terabits per square inch – 30TB to 60TB for 3.5-inch drives and 10TB to 20TB for 2.5-inch drives.
The 1-terabit per square inch achievement represents a 55% increase over today’s areal density ceiling of 620 gigabits per square inch, and the 3TB maximum capacity of today’s 3.5-inch hard drives, with 2.5-inch drives currently topping out at 750 gigabytes (GB), or roughly 500 gigabits per square inch. HAMR's first-generation drives will likely more than double these capacities – to 6TB for 3.5-inch drives and 2TB for 2.5-inch models.
Much like PMR and unlike the Beta/VHS videotape format wars, HAMR is being accepted by the major disk vendors and their supply-chain partners – media and read/write head suppliers – says Re. “The entire industry is following this approach,” he says. “There's not enough of us to do that (Beta versus VHS) anymore.”
Seagate has been working with HAMR, which uses a combination of a laser and magnetic write heads that allows bits of storage to be packed more tightly together on a disk platter, for over a decade, says Re, and first demonstrated the technology in 2002. He says the technology is somewhat evolutionary and should be pretty transparent to the customer base.
Although the track record for predicting what the end-user prices will be following a technology transfer have not been good, says Re, the intention is to have the costs be somewhat transparent to customers. “I don't see a radical change in cost.”
Between now and the expected release date of 2015 for the first commercial HAMR-based HDDs, Seagate will be working on ensuring the reliability that customers expect, he says, as well as the more mundane activities of getting the factories and supply chains prepared for the changeover.
Looking beyond HAMR, Re says Seagate is working on Bit Patterned Media (BPM). He says once the industry has transitioned from PRM to HAMR, he expects to see BPM being combined with HAMR to fuel future growth. What he doesn't expect to see in the foreseeable future is the disappearance of disk in an all-flash storage world. “It's still cost-prohibitive to replace even a small fraction of what we produce in disk storage.”
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