It's as easy to lose big numbers as small ones

This AP story on CNN reports that a technician accidentally erased a disk containing the accounting records for a $38 billion account, and the backup disk.

JUNEAU, Alaska (AP) -- Perhaps you've experienced that sinking feeling when a single keystroke accidentally destroys hours of work. Now imagine wiping out a disk drive containing an account worth $38 billion.

That's what happened to a computer technician reformatting a disk drive at the Alaska Department of Revenue. While doing routine maintenance work, the technician accidentally deleted applicant information for an oil-funded account -- one of Alaska residents' biggest perks -- and mistakenly reformatted the backup drive, as well.

There was still hope, until the department discovered its third line of defense had failed: backup tapes were unreadable. "Nobody panicked, but we instantly went into planning for the worst-case scenario," said Permanent Fund Dividend Division Director Amy Skow. The computer foul-up last July would end up costing the department more than $200,000.

Backing up your data regularly is important. So is checking your backups to make sure they contain what you think they do and can actually be used to restore lost data. I say this from bitter personal experience.

I also have anecdotal evidence that a major New York bank once had a more expensive data loss than the one reported in this story. The main database was corrupted by a software error. Then the operators mounted the backup disks and did what they did every night: copied the database onto the backup disks...