Saying that people who deal with storage--from the largest corporations to home-computer users--find themselves in the middle of a swirling cauldron of change would be an understatement. At the enterprise level, not only does virtually every week bring an announcement about progress in a new storage protocol or standard, but the entire storage infrastructure is clearly undergoing significant restructuring on several levels.

Companies are moving away from DASD to Network Attached Storage (NAS) and Storage Area Networks (SANs) at an accelerating rate. And as enterprises redesign their storage infrastructures, they're also rethinking their approach to backup, restore, and disaster recovery. Increasingly, disk technology is elbowing its way into the storage hierarchy as a new tier for near-online storage. These days, data often moves from expensive disk drives to less expensive disk drives before being transferred to tape for archiving.

Storage is quietly undergoing a significant change at the desktop as well. Industry graybeards probably remember when a hard disk drive and a floppy drive were standard equipment on desktop computers. People would dutifully save and, after the capacity of hard drives increased, back up their most important files to a floppy disk. The really responsible users among us would add a low-end tape drive for backup.

Of course, those days are long gone. Now, most home computers come equipped with at least 40GB of storage and have some form of rewriteable optical media. The use of tape as a backup medium for home computing has shriveled.

An enabling technology for the changes in storage at both the enterprise and the home level has been the development of low-cost, high-capacity hard disks. In recent weeks, the next step in the application of low-cost hard disks to backup applications has emerged. In mid-April, Iomega began shipping what it calls its REV drive, a removable hard disk drive. Shortly thereafter, Spectra Logic unveiled what it calls RAID Exchangeable TeraPack (RXT) portable disk technology, which packages Serial ATA (SATA) disks for use as removable media in a tape library.

Although the Iomega and Spectra Logic offerings take aim at opposite ends of the market--the Iomega drive is for home and small-business users whereas the RXT technology is for use in corporate tape libraries--the concept behind them is the same. Instead of being able to remove media from a fixed drive, users can remove and store the entire drive.

"The RXT is at the intersection of disk and tape. It is the first removable hard drive for data protection," said John Woelbern, a former Sony executive now consulting for Spectra Logic. The RXT, he added, combines the higher performance of disk technology with the removability of tape.

Although Spectra Logic intends to use the initial RXT product in its own tape libraries, it plans to release a standalone version later this year. The RXT media pack, which will be available in third quarter 2004, will run in a tape emulation mode. Tape libraries will be able to run a combination of RXT media packs and traditional tape cartridges. Both the disk drives and the tapes will be removable for off-site storage. The RXT will offer storage administrators more flexibility in their backup and restore options without requiring them to add a tier to their storage infrastructure.

In contrast, Iomega is aiming its removable hard drive squarely at the home and small-business arena. In addition to millions of home workers, market research firm IDC estimates that 7.9 million businesses in America have fewer than 100 employees and 93,000 companies have from 100 to 999 employees. Iomega officials believe that many of those individuals and companies simply don't back up their data to tape because tape is too slow, expensive, and difficult to use.

The REV drive, which has a compressed capacity of 90GB, is intended to compete at the low end of the tape-drive market, which includes Digital Data Storage 4 (DDS-4), DAT 72, AIT-1, and DLT VS80. IDC forecasts that this end of the market will represent about one million units this year.

The low cost of these disk drives (a 35GB REV disk retails for $59.99; the entire unit, which includes one drive, is priced at $399.99) is only one enabling factor underpinning the Spectra Logic and Iomega announcements. The quality of the drives and drive mechanisms has also improved. "The MTBF \[mean time between failures\] as well as the shock and vibration specs are outstanding. It is really viable for removable applications," Woelbern said of the RXT. Indeed, if these new offerings meet their manufacturers' expectations, removable SATA could emerge as new backup technology for everyone from serious home users to the largest corporations.