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Drives Get Bigger, Faster, Cheaper

9.1-GB drives spinning at 7200 rpm will soon enter the mainstream.

Seagate's new 9.1 -GB drive is expected to sell for around $495 when introduced early next year.

espite many competing tech­nologies, hard disk drives continue to hold their domi­nant position as the medium choice for data storage. The price of hard disks continues to plummet, while capacity and performance climb upward. Seagate and Quantum are expected to ship 9-GB Ultra2 SCSI drives in mid-1998. The 3.5-inch-factor drives, which stand just 1 inch high, spin at 10,000 rpm.

The higher the rotational speed of the disk drive motor the greater the data transfer rate, and the lower the seek and latency times when the head switches tracks. Today, most hard disks spin at 5400 rpm, with higher-end models attain­ing a speed of 7200 rpm. The Seagate Bar-racuda, Quantum Atlas, and Micropolis Tomahawk 7200 drives have become popular in multimedia applications such as digital motion pictures.

Seagate is already shipping its first 10,000-rpm disk drives, the Cheetah fam­ily. With formatted data transfer rates peaking at 16.8 MB per second (around 40 percent better than top 7200-rpm hard drives), and prices around 40 percent higher than equivalent 7200-rpm offer­ings, these 4.5- and 9.1-gigabyte drives are currently limited to niche market appli­cations. Early next year, however, Sea­gate will sell a new drive, the Medalist Pro 9140, that has a 9.1-GB capacity and spins at 7200 rpm. Street price will be about $495, according to Denise Lippert, prod­uct marketing manager.

Not all agree that high-end 10,000-rpm drives are a viable business right now. David Rawcliffe, marketing director of Quantum Asia-Pacific, says Quantum will offer 10,000-rpm models in mid-1998, when 10,000-rpm drives might have 15 percent of the high-end hard disk mar­ket. Quantum's first 10,000-rpm entries are expected to hold 9 GB and 18 GB, with

either Ultra2 SCSI or Fibre Channel inter­faces. Rawcliffe also expects 10,000 rpm to remain the top hard disk rotational speed until early next decade.

Magnetoresistive (MR) heads, used by IBM and Quantum, helped achieve the next level of capacity by separating the read and write functions into two physi-

cally distinct heads. An inductive head, optimized for writing information, is integrated with the MR structure opti­mized for reading. MR heads are usually coupled with partial response maximum likelihood (PRML) channel recording for resolving data pulses from the disk sur­face. While the initial troubles in manu­facturing MR heads limited their use to very high-end drives,'the yields have improved in the past two years. Major vendors like IBM, Quantum, and Seagate use them in many mainstream IDE drives.

The next step, Giant MR (GMR), en­abling recording density in tens of giga-

bits per square inch, is expected to arrive next year in some 3.5-inch drives with ca­pacities well above 10 GB. Western Digi­tal is already shipping UltraATA IDE devices with 2.16 GB formatted capacity per platter (6.4 GB for a three-platter hard disk) using MR head technology. In 1998, MR heads are expected to overtake the

old inductive ones in terms of number of units shipped, analysts say.

Besides GMR and improvements to PRML, like IBM's PRML with digital fil­tering, new technologies like multilevel decision feedback equalization (MDFE) are expected to help achieve even higher capacities. Developed by Singapore-based Data Storage Institute, MDFE is expect­ed to surpass PRML and its derivatives in recording density and performance.

On the high end, dual-head parallel drives, pioneered by Seagate, didn't make it in the market. Seagate dropped its 2-GB Barracuda 2HP two years ago, with no


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