A PHOTO CAPTION ACCOMPANYING A REVIEW OF DATA-STORAGE SYSTEMS IN THE AUG. 19 BUSINESS SECTION INCORRECTLY IDENTIFIED A DISK. THE PRODUCT THAT WAS CALLED AN IMATION SUPERDISK WAS A CONVENTIONAL 1.44-MEGABYTE DISKETTE MADE BY IMATION CORP. (PUBLISHED 09/02/99)

One of the most enduring pieces of technology in any computer today is the 3 1/2-inch floppy drive. It has no fans and no groundswell of support to protect its dominance. So why has it endured?

In a word, openness. Every computer with a 1.44-megabyte floppy drive can read and write to the same disks--arguably the most successful example of standardization in PC history. To supplant the floppy, a replacement standard will have to be just as widely accepted.

The Government Computer News Lab recently took a look at the latest 250-megabyte Zip drive from Iomega Corp. of Roy, Utah, and two SuperDisk drives from Imation of Oakdale, Minn.

One SuperDisk drive attached to the test computer's parallel port, as the Zip drive did. The other SuperDisk drive was designed for use on a notebook computer, attaching by means of a PC card.

I installed all three drives on a notebook. None was difficult to get up and running; all three came with the necessary drivers and software. The two parallel-port units needed access to a power outlet. The SuperDisk that attached by means of a PC Card could draw enough power from most notebook batteries through the PC Card slot.

While a floppy is just a floppy, floppy replacements are removable storage systems with bells and whistles that fall into three categories.

* The first category is the "navigation aid," which usually offers to help find data on the disk--something Microsoft Windows already does well. Such navigation tools clutter up a usable and familiar interface. Tools that come with the Iomega Zip drive fall into this category.

* The second category is the "performance enhancer," which usually sets up a disk cache and file buffer on the hard drive. With this option, a file directed to a SuperDisk is written to the hard drive first, then to the diskette. This saves time and also speeds up the opening of frequently used files; if a copy of the file exists in the hard-drive cache, it will load faster from there.

* The third tool category, also included with the Imation drives, encrypts files with a password. Encrypted and unencrypted files can be stored on the same diskette; the encrypted files are accessible under a separate drive letter. This gives the user two disks in one: a disk that anyone can get into, and a second that acts as a virtual lock box.

While not foolproof, this feature provides an extra degree of protection for sensitive information. Of the three tool categories, the security tool is easily the most useful.

Iomega makes Zip drives in 100-megabyte and 250-megabyte sizes. The Zip 250 drives can read the 100-megabyte cartridges but not standard floppies. The Imation SuperDisk drive stores up to 120 megabytes on a proprietary disk--and it can also read and write from the ubiquitous 1.44-megabyte floppy disks in use today.

The Iomega Zip 250 drive was the best performer, trumping the parallel-port version of the Imation SuperDisk. The Zip's performance advantage dropped against the PC-card-based SuperDisk, which had the advantage of a much faster interface.

If the speed with which you can get into disks matters, the Zip drive is the best bet. But even the slow parallel SuperDisk was faster than a standard floppy and gave more than 80 times as much storage space.

Buyers will want to consider cost when shopping for floppy replacements. For only a little more money than the cost of the Imation unit, the Iomega Zip 250 can deliver twice as much storage with good performance.

Both Iomega's and Imation's offerings can make good floppy replacements, but I have to give the Reviewer's Choice designation to the Iomega Zip 250. The SuperDisk's security options and backward compatibility with standard 3 1/2-inch floppies are attractive, though without a strong price advantage, and performance is uninspiring.

CAPTION: From left, the 120-megabyte Imation SuperDisk; a 250-megabyte Iomega Zip disk; and the waning champion, the familiar floppy.