Everything's changed. CPUs sizzle, hard drives are huge, files are fat, and floppy drives... well, floppy drives are just what they've always been: small and slow.

Fortunately, many removable storage products bridge the gap between the 1.44MB floppy and today's multigigabyte hard disks (see A gig in your pocket, April 1998, p74). And a couple make excellent floppy replacements. But choosing the right one involves looking at more than megabytes and dollars.

If you back up lots of data regularly ù all the contents of a 1GB hard drive, for example ù you need a removable hard drive. SyQuest's SyJet and Iomega's Jaz offer cartridges of a gigabyte or more, good data transfer rates, and low per-megabyte costs. Pick a drive by balancing the size of your data against the size of your wallet.

But removable drives don't completely substitute for the old floppy. Because the cartridges are based on hard disk technology, they're expensive and delicate. And since there's no cartridge standard, you probably won't be able to swap data with many of your friends or colleagues.

If your needs are more moderate ù for example, backing up or swapping big individual files such as graphics or multimedia presentations ù you'll do fine with Iomega's 100MB Zip drive or with a 120MB drive that uses LS-120 ("SuperDisk") technology (Imation and several other companies make them). These two alternatives are vying to succeed the floppy drive and become standard on high-end systems from vendors like Compaq and Hewlett-Packard.

Zip drives enjoy the advantage of already being everywhere, which makes them the choice for anyone who wants to share files with many other users.

But LS-120 drives offer the all-in-one convenience of reading and writing both 1.44MB floppy disks and their own 120MB disks (though a traditional floppy drive may not be able to read a 1.44MB floppy formatted on a parallel port LS-120 drive). And the LS-120 boasts a small size advantage over the Zip disk.

Both Zip and LS-120 force you to make some trade-offs regarding the type of data connection. If you're buying an external drive, you can choose either a SCSI or a parallel port model. SCSI carries with it the hassle of buying and installing a SCSI adapter (if you don't already have one), but it's also a lot faster. Parallel port drives typically run at around 300KBps (taking approximately two minutes to transfer the whole disk); SCSI drives can move data at more than three times that rate.

And if you don't mind popping the top off your PC, you can achieve data rates of better than 1MBps by purchasing and installing an internal EIDE model of either a Zip or LS-120 drive.

The next time I buy a new computer, I'll probably ask the vendor to install an internal EIDE drive, a type that tends to be slightly cheaper than external SCSI or parallel port drives. I prefer the convenience of a 1.44MB-floppy¡compatible LS-120 drive. But if the manufacturer doesn't offer that option, I'll choose an internal EIDE Zip drive rather than installing an LS-120 myself ù in order to avoid potential compatibility bugs and other troubles.

LS-120, Zip, and other removable storage devices have had their share of growing pains. So do a little quick homework before you buy, and you'll avoid (or at least minimise) bugs and incompatibilities. Search Microsoft's Knowledge Base (support.microsoft.com/support) for details on your specific drive. For example, Windows 95 has problems recognising removable IDE drives in Windows Explorer. You'll find instructions for applying the fix in Article ID: Q153471 of Microsoft's Knowledge Base.

If you're booting from a removable drive (so that multiple users can share the PC or one user can run multiple operating systems), you should know about a bug in Windows 95's original release (OSR1). Performance can be slowed dramatically by a bug on some IDE and SCSI drives from Iomega and SyQuest and on some laptops using various removable hard drives. Instead of loading the 32-bit protected-mode drivers that Windows 95 normally uses to control virtual memory, OSR1 uses the older and much slower DOS-mode drivers.

To check, open Control Panel and click the System icon and then the Performance tab. If it says 32-bit next to Virtual Memory, you're OK. If not, the fix is to force virtual memory to reside on your hard disk. To do this, go to the Performance tab and click the Virtual Memory button.

On removable drives with pass-through parallel port connectors, watch out for a common conflict between an attached printer and the drive. Several makes of printers that send data back to the PC, including HP models, can confuse both the external drive and Windows 95 so that the drive is not recognised. You can usually solve this problem by installing an updated printer driver. Always check with your printer vendor for potential incompatibilities before attaching a removable drive. Better yet, avoid the problem entirely by purchasing a SCSI or IDE drive.