Notebook Hard Drives Hold More

Dave Andrews

Hard drive manufacturers are using several technologies to satisfy the demands of notebook users who want smaller, lighter, more powerful machines. IBM's latest 17 mm high, 2.5-inch hard drive, the TravelStar XP (AT interface version expected to ship in June; SCSI version in July), uses a number of technologies, including magnetoresistive heads (instead of thin-film heads), to get increased areal density. The result is a 1.2-GB hard drive for notebook computers. In August, another hard drive manufacturer, Toshiba America, is expected to announce a 1-GB hard drive designed especially for the notebook market.

The most intriguing announcement this spring might come from Integral Peripherals (Boulder, CO). Its Platinum/SL drive, which is expected to start volume shipments in the third quarter of 1995, will offer a native capacity of 1 GB in a 12.7 mm high, 2.5-inch drive. Price for the drive to manufacturers will be about $795 (compared to about $790 for IBM's 1.2-GB AT interface TravelStar XP drive), and Integral says this price will drop over time. The 1-GB capacity is a giant leap for small notebooks such as Digital Equipment's HiNote Ultra, which uses 12.7-mm hard drives, with a current maximum storage capacity of 340 MB. Integral uses a number of technologies, including dynamic head loading (see the figure "Integral Glides into 1 GB" ), to allow these higher capacities.

Rich Liguori, program manager in Digital's mobile computing group (Acton, MA), explains that these hard drives typify the industry's move to smaller, lighter systems that minimize compromises. He also notes that although the difference between a 12.7-mm drive and a 19-mm drive used in a desktop system might appear to be minute--it's roughly equivalent to the width of your pinkie fingernail-- the difference is enormous to engineers developing small notebooks. As Liguori says, "Every millimeter counts."

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Integral Glides into 1 GB

illustration_link (19 Kbytes)

CONVENTIONAL

Conventional small disk drives use textured platter surfaces and a relatively large flying height for the read/write heads. Surface irregularities are deliberate: They help create pockets of air that help prevent the drive head from sticking upon spin-up and take-off from the platter, but they also force the head to fly higher.

DHL

Dynamic head loading features highly polished recording media combined with a specialized head to eliminate contact between heads and recording media and to allow lower flying heads. Head tilt angle is also reduced, minimizing the possibility of head-corner contact with the platter.