You can rent a computer system, delivered anywhere in the U.S., for as little as $126 per month by calling the Personal Computer Rental Corporation, (800) 444-9930. You might save money, though, by buying a used computer and then selling it when you're finished. (For long-term business use, you can deduct depreciation on your U.S. income taxes. If purchased new, there is a full deduction for the first $10,000 of equipment each year.) Be sure that you don't leave valuable data on any computer that you return or sell. Just erasing the files, or even initializing the disk, won't provide total security. (Apple once lost a new operating system when a reporter bought one of their used office Macs.)

When selling a computer, don't give out your home address to anyone you can't identify. Thieves sometimes target advertised computer systems and the upgrades that are replacing them. (Discussion of expensive home computer/stereo systems on network bboards has also been known to trigger burglaries.) To show the system in your home, ask to call back with an appointment time. Call several hours later, at a random time, to be sure that the prospect isn't using a public phone. (Anyone knowing your name, city, and phone number can look you up in the phone book, though.)

Protect your home computer by inscribing your driver's license number on the outside and inside of the case. Keep a set of backup disks off-site to protect against both fire and theft. Your address list and other critical files should be kept in triplicate, since floppies and hard disks do fail. (In fact, it's part of the normal life cycle.) Data recovery, if possible, can take weeks and cost hundreds of dollars. Repair personnel have also been known to keep copies of files they find on your disks.

Take special care with encrypted files or disk partitions, since a single-bit error may trash the data. If a floppy does fail, don't stick your only backup in the drive until you've verified that the drive itself is not at fault. Also, keep your backup disks locked; never take a chance on infecting them with a virus.

Sometimes it's the index to your backup set that fails. (I've had this happen.) If so, you'll have trouble recovering your data unless files are stored in an independently readable form. I use DiskFit for the Macintosh, which stores readable files and uses a near-minimal number of disks. (I've heard that Redux is even better.) Another protection is to alternate two or more backup sets -- plus periodic archival sets to guard against writing a newly corrupted file to all your backups!

A collection split between floppies and a hard disk can be very difficult to maintain. There are shareware cataloging programs, of course, but the conceptual problem of tracking what backs up what (i.e., version control) is not solved by cataloging. I recommend the following. Whenever you get new software, lock and then copy each disk -- anything worth keeping is worth keeping in duplicate. (Avoid copy-protected software; it will eventually fail, and then what will you do?) These copies become your primary set, with the original disks as a first backup. Keep the originals in a different room from the computer, just in case thieves take all the disks in your office. Make a second backup of any disks that are particularly valuable or irreplaceable, and keep them off-site in case of fire, earthquake, or even seizure by IRS/Federal agents.

Now -- or during the previous copy steps -- put any files that you need onto your hard disk as a working set. Omit files that you don't need -- or seldom need -- and never load an extra copy of the operating system. The only "primary" files on your hard disk will be data files that you create, and these can be copied to "working backup" floppies when you first write the files or at the end of each day. Periodically make extra copies of these working floppies to store with your primary and backup sets.

With this system, you really don't need a backup of your entire hard disk. Nor do you need special recovery programs like SUM Guardian, MacTools MIRROR, or Complete Undelete. Still, they're a comfort -- and the backup programs can help if you want to repartition your disk, defragment files, or restore a pre-virus state. Unfortunately, it takes at least an hour and 40 DS/DD floppies to back up a 40MB hard disk. Times the number of backup sets. That's a lot of floppies, but it's cheaper than losing data. [Buy mail-order floppies, in bulk. MEI/Micro Center ((800) 634-3478) sells 3.5" DS/DD disks for about $.41 delivered. If any fail to initialize, they'll ship you replacements. Store prices are two to five times as much, with perhaps another eight cents per gummed label. (!) Discount brands are almost as reliable as name brands, and any floppy that accepts initialization is unlikely to give you trouble for at least three years.]

A second hard disk can simplify backing up the first one (if you can spare the space), but creates additional problems if you fill up its larger store with new files. If I ever win the lottery, I'll invest in a cartridge drive (about $600, plus $80 per 45MB cartridge). Thank goodness 600MB CD ROMs don't need backups.