By Hal Glatzer

Sales are booming for the smallest hard-disk drives, as consumer electronics shrink in size. The tiniest drives, with platters 0.85 inch in diameter, are at the heart of standalone, removable storage devices, while larger 1.8-inch drives are installed in handheld computers, laptops, portable GPS devices and MP3 music players.

Toshiba, one of the market leaders, announced last week that it has shipped more than 25 million 1.8-inch drives.

"Toshiba manufactures almost one-and-a-half million 1.8-inch drives a month," Maciek Brzeski, vice president of marketing for Toshiba's storage device division, told internetnews.com.

"We were the first to make the 1.8-inch drive the standard [hard disk drive (HDD)] for mobile media players. But with recent moves toward storing video clips and TV shows in small, portable devices, we expect demands for higher capacities."

Indeed, platters with only 20GB capacity are "on the way out," Brzeski said, in favor of 30GB platters, two of which can be installed in a single drive, for a 60GB total capacity.

But Toshiba -- and its competitors –- are starting to incorporate perpendicular magnetic recording (PMR), a new recording technology which promises far greater capacities.

In today's HDDs, the magnetic particles lie flat in their recording layer, like sardines in a can. If the sardines were turned so they stood upright, more of them could be packed together in the same size container.

Similarly, turning the magnetic particles in a hard-disc's recording layer so they stand up increases a platter's storage capacity.

Toshiba manufactures 0.85-inch HDDs with longitudinal magnetic recording (LMR) technology, which gives them 2GB and 4GB capacities. But with PMR, Toshiba researchers have more than doubled the capacity of a 0.85-inch platter to 10GB, and Brzeski expects the company to commercialize a PMR drive in the 0.85-inch form-factor by the end of 2007.

Toshiba's 1.8-inch LMR drives have 30GB and 60GB capacities (depending on whether a drive has one platter or two). Since last August, Toshiba has been shipping 1.8-inch drives with PMR technology that have 40GB and 80GB capacities.

Its competitors are also moving toward PMR.

Seagate has announced a 2.5-inch HDD with 160GB capacity. And the company promises an 8GB version of its 1.8-inch pocket hard drives, which currently use LMR technology that already holds 5GB and 6GB.

Hitachi expects to ship HDDs with PMR in 2007, with a 1-inch HDD specified to hold 20GB, and a new PMR-enabled 3.5-inch model Deskstar, which could reach 1 terabyte. (define)

But HDD manufacturing is still a customer-driven business.

"We can get to 80GB platters with LMR," Brzeski said. "But we have to pace the transition to PMR for our volume production lines, as our consumer electronics and PC customers can absorb them.

"There is still a large market for LMR drives, especially in applications where the highest possible storage capacity is not required."

The automotive market, for example, does not demand new or upgraded products as quickly as the CE or PC markets do. Car manufacturers may need higher-capacity drives only every three or four years or more.

Brzeski also notes that the current generation of LMR drives have been well-tested in the field and perform well in extreme temperature ranges of automotive installations.

"PMR is more limited right now by the availability of heads and media," Brzeski added, "than by the production capacity for building the drives. There's still a premium [price] for PMR media.

"So the question for us is: Do we put PMR on our highest-end drives, or do we offer it across our product lines and increase our total volume? We'd love to get there [i.e. transition to PMR] tomorrow. But our suppliers can't switch over in one generation, either."