When a lawyer accidentally put his car into reverse and drove over the laptop to which his firm had entrusted 10 days' worth of court notes, the phrase backing up on the computer took on a whole new meaning.

That's not the kind of backup that data doctor Mark Adam has in mind when he urges computer users to store data frequently. But it was to Adam's computer-data-backup start-up -- Orbis, in Auburn, Mass. -- that the solicitor rushed the roadkill, and there that its wound was judged terminal.

Not all causes of data loss are that clear-cut -- or unsalvageable. More common is the ordeal of the small business that was dependent on its personal computer to bill some 1,000 customers. Its database performed flawlessly month after month, until it was open during a power outage. When the electricity came back, the screen flashed an alarming "system error" message. As bad luck would have it, the company was due in small-claims court, where it would need its accounts-receivable histories to document delinquency claims. Adam was able to reassemble the figures.

To Adam -- a software engineer who recognized a business opportunity when an associate's disk failure wiped out an irreplaceable body of work -- each situation illustrates the potential for catastrophe with high-capacity disks. "What tend to go nowadays are individual configurations that took years to build," he observes. Accordingly, Orbis ministers to two causes: getting users to back up disks, and doctoring damaged data when they don't.

It's not so much that disks break, Adam finds, as that disks erase. "What we hear most from clients is 'I wonder where my files went." Data can disappear months after a software program has been installed. Such viruslike havoc is on the increase because it's impossible to test every pathway in today's massive software programs, which run more than 200,000 lines of code.

Nor is saving to a network always the answer, notes Adam. "A typical small-company network server gives each user a mere 20 megabytes of storage -- not nearly enough to store a personal hard disk's contents, which usually occupy 200 MB."

Yet most small companies leave it to employees to back up their disks. Come Friday, that procedure is the last chore they want to undertake. And among the few who do, the majority stash their backup tapes in desk drawers, where they're vulnerable to the same hazards that the parent PCs are. One solution is to have someone else do the backup -- a service offered by companies such as Orbis, which backs up tapes off-premises for $60 per system per month. Alternatively, Orbis charges $50 an hour to restore unbacked-up data -- though it doesn't make any guarantees.

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A study by International Data, in Framingham, Mass., says it takes 19 days and costs $17,000 to re-enter just 20 megabytes' worth of sales-and-marketing data. The figures for the same volume of accounting data are 21 days and $19,000. n