Remember when the most portable storage capacity was the 1.44-MB floppy disk? Remember how the Zip drive and its 100-MB disks were a godsend and changed our ability to share and back up files? Plenty of Zip drives are still used today, but file sizes are growing, and even the 250-MB capacity of newer Zip disks isn't always enough for a home PC user now filling a hard drive with movies, digital photos, tax returns, audio files, and—oh, yeah—work. So Iomega Corp., in San Diego, Calif., which introduced the Zip in 1995, is taking a giant leap with a new 35-GB format called the Rev .

Rev made its debut at the Comdex show in Las Vegas, Nev., in November, but it won't hit retailers' shelves until March. Prices will be set then, but expect them to be in the neighborhood of US $300 to $400 for the drive and one disk. Extra removable rigid disks (RRDs) will run $49.

The new drive relies on giant magnetoresistive heads, usually found on read heads of laptop hard drives, to read from and write to the disks at a maximum rate of 22 MB/s. The speed is comparable to hard drive transfer rates. In round numbers, it would take just 10 minutes to back up 20 GB from your hard drive using standard 2:1 data compression.

Businesses that back up their data should find the price of the Rev very attractive. Their usual backup medium is tape, and such systems can cost as much as $1500. What's more, they're slow, with an average transfer rate of a pokey 3 MB/s. (Home PC users most often skip the backup step entirely.) Another drawback of tape backup is that it's sequential. To find the file you need, you must advance the tape to the right spot, just like fast-forwarding a videotape to reach a favorite scene. But the RRD cartridge is like a DVD; it's random access, and you can go directly to the scene or file you want without scanning everything that comes first.

Because the Rev's drive heads are sensitive to dust, the drive itself is always sealed except for the split second when a disk is inserted. The drive and disk form a sealed unit around the drive heads and disk media upon which your data is actually written for storage and retrieval. The disk cartridge itself is sealed when not in use and sealed in operation. When the cartridges spin up, a HEPA filter inside the drive removes any dust that may have entered with the disk, and an automatic head cleaner makes sure that everything stays clean.

The spindle motor has also been altered to eliminate dust. The motor is sealed within the RRD cartridge to eliminate the spindle hole and any dust it might have brought into the drive. Most of all, the motor is quiet. The older Zip drive on my desk lets me know with a burst of noise every time it spins up, but even the preproduction beta version of Rev used to demo the technology went through its paces silently in the IEEE Spectrum offices.

At 22 by 92 by 27 mm, the 180-gram drive is smaller than a deck of playing cards, and fits a standard half-height drive bay, usually used for a 3.5-inch floppy drive. And at just 10 by 78 by 72 mm, the 75-gram disks don't take up much space, but can each hold 70 000 photos, 50 hours of MP3 audio, or 2.5 hours of video. The disk medium is more durable than tape: it's good for over 1 million rewrites versus tape's few thousand. Advanced two-stage error-correction circuitry ensures data integrity.

For the home system owner nervous about tape backup and put off by having to install the SCSI connector that tape systems need to operate, the Rev plugs into a USB 2.0 port or can connect internally as a standard ATAPI hard drive. Once connected to the host computer, it appears as a regular drive with a letter designation, just as CD and floppy drives do. For businesses looking to back up servers, SCSI and S-ATA Rev drives are planned.

Iomega (http://www.iomega.com) is designing the drive to work with popular backup and disaster recovery software packages, but Rev comes with basic software for these tasks. Like Zip before it, Rev can also be used as an emergency boot disk. The drive is bootable even if your hard drive crashes. Now that $300 price tag could mean there's no reason not to back up your movies, photos, tunes, taxes, and all that work brought home every day.

Photo: Iomega