The one component of your PC that causes more headaches than any other if it goes down is your hard disk. Every other part can be replaced without the same aggravation. Even if your data is backed up every day, your applications generally are not. Even if your network can clone your PC after the new disk has been installed, it will never be exactly the way you left it, because you keep setting your own preferences in individual applications.

If your data isn't perfectly backed up, and your network administrator can't clone your machine, you're in for a day of re-installing all your applications. And then there's, "Oh God, I forgot which sequence to install them in, and when I installed them in the wrong order, I had to make 10 tech-support calls to the software vendors."

A marvelous way to prevent this is RAID 1 -- mirrored hard drives, so that everything is written to two disks simultaneously, and if one crashes, the other will keep you going. Only problem: Replacing your cheap IDE drive with a couple SCSIs, plus a RAID controller, costs at least a grand. Buying a fancy RAID box will set you back $2,000.

Dilemma, dilemma ... unless you DupliDisk your PC. Arco Computer Products has a slick PCI controller that lets you keep your cheap, crappy IDE drive in your machine, and all you have to do is buy another one equally as large and equally as crappy. You plug DupliDisk into a PCI slot and install the new drive as another master, not a slave. Then you yank the cable out of your old drive and plug it into the DupliDisk. From the DupliDisk, you plug one cable back into your old drive and one into your new drive. That's it.

You boot up in DOS and use the supplied utility to copy the data from the master to the mirrored drive. Then go home and throw out your Advil. If the C drive fails, you won't even know it, except for the constant beeping from the card, which you can silence. Then, replace the failed drive with another cheap, crappy one, run the utility program, and you're protected once again.

DupliDisk costs $225, and there's a drive-bay version if you don't have a slot available. I'm sleeping better at night. I hope it will help you, too.

Arco Computer Products Inc. can be reached in Hollywood, Fla., at 800/458-1666 or online at .

Alan Freedman's award-winning Computer Desktop Encyclopedia on CD-ROM is the reference about the computer industry. It contains more than 11,000 entries from micro to mainframe and includes technical drawings, photographs and charts. It runs on Windows 3.1, 95/98 and NT. CD-ROM and floppy are $44.95 each. Contact The Computer Language Company at 215/297-8082. Fax: 215/297-8424.

December Table of Contents