"How can that be?" you ask. Isn't solid-state memory fantastically cheaper, smaller, lower-power? As with all things technology, the answer is, "It depends."

Until 2000, using MR-HDDs in noncomputing applications made up less than 2 percent of disk drive unit shipments. In 2004, non-PC applications will consume slightly more than 13 percent of drives shipped and, by 2008, non-PC drive consumption will hit nearly 25 percent.

The first wave of this change was initiated by the launch of personal video recorders containing MR-HDDs by TiVo and ReplayTV in 1999. Though the original 12-hour units were pricey, an 80-hour TiVo box now runs about $250 plus service fees. For the record, TiVO now has more than 1 million subscribers.

PVRs are big enough to accommodate larger-form-factor 3.5-inch desktop drives. But smaller drives were needed to enable the next wave of adoption of MR-HDDs in consumer electronics. So, along came the Apple iPod MP3 player with Toshiba's 1.8-inch drives. Last year alone, Apple sold 1.4 million iPods. The new iPod mini sports Hitachi's 1-inch drives.

The third wave is in its infancy as cell phone makers consider integrating sub-1-inch drives into cell phones to support storage-intensive applications like MP3. Doing its part, Toshiba has disclosed a 0.85-inch drive (just bigger than a quarter) that will be priced around $125 per Gbyte. By comparison, 1 Gbyte of flash memory costs about $160.

The factors to consider for including MR-HDDs in cell phones include size, power, price, capacity, performance and shock-tolerance. Surely, a number of cell phones will be designed with MR-HDDs. As to whether they will become mainstream, there are as many naysayers as supporters. Time will tell.

Jeremey Donovan (jeremey.donovan@gartner.com) is chief analyst at Gartner Dataquest.