Deleted a file by mistake? Good news: All is not lost

November 09, 1992|By Neill A. Borowski | Neill A. Borowski,Knight-Ridder News Service

The boss spent three weekends typing a new budget into a spreadsheet. Now it's your job to copy it. OHMYGOSH! It's gone! You've erased the boss' work from the computer!

Don't despair -- your job is not lost.

In fact, the erased file probably isn't lost either.

While resurrecting erased files is second nature to experienced computer users, the retrieval of "lost" data seems downright mystical to many new or occasional users.

"Being human, we all will erase things," says Marty Rubenstein, product manager for Norton Utilities, a package of computer programs that among other things will undo the errant erasure.

Programs such as Norton Utilities, Norton Desktop and a competitor, PC Tools, and even DOS 5.0 will "unerase" the erased or deleted file on a hard or floppy disk. The programs sell for less than $150 and in some cases, discounts on them can be deep.

If you're buying a computer for your business -- even if you're the only user -- spring for the program. If you're buying a computer for home use and are doing anything more involved than writing letters to relatives, it also would be a good investment.

A disk works in much the same way. Erasing doesn't mean obliterating. After erasing, the first letter in the name of the erased file is changed in an IBM-compatible system (using MS-DOS, the operating system used by most personal computers today). The change in that one letter tells the system that the file has been tagged for erasing and the space it had occupied on the disk can be overwritten.

It might take some time for DOS to get around to using that space, however. "DOS is pretty lazy when it comes to erasing a file," the Norton documentation notes.

Even weeks after they've been erased, some files might be retrievable. Or, parts of them may have been overwritten, permitting the user to get back at least portions of the files.

Later versions of Norton have an "erase protect" option, which can be turned on automatically each time the computer is turned on. If there are several users on your computer and the computer's hard disk isn't short on capacity, it would be wise to use this option.

"Erase protect" permits users to erase files, but, as Rubenstein explains, it also builds a picket fence around the erased file and protects it from being overwritten. When the erase command is used, the file is sent to a hidden subdirectory appropriately named TRASHCAN. When the user sets up the erase protect option, the trashcan of erased files can be ordered emptied every day orup to every 99 days. If something is mistakenly erased, getting the file back is only as complicated as calling it up from another subdirectory.

The ability to resurrect erased files also raises another issue that shouldn't be overlooked by the security-conscious user.

Suppose your love letters or company payroll statements reside on a floppy disk. You no longer need those files, so you use the ERASE command to erase everything on the disk.

A few days later you make a copy of something for a co-worker or customer and use the recycled floppy. If the other person is nosy enough, a utilities program will unerase much (if not all) of what you thought you had erased and everything from personal to competitive information will be alive again and in someone else's hands.

What to do?

Reformat the disk, which makes it more difficult to get at the erased data. Or, use another utility, which Norton calls WIPE. If you "wipe" a file or disk, the utilities program overwrites all of the information with 0s.

If you're really touchy about what's on the disk, you can select the "government wipe" option (up to Defense Department standards) that can overwrite the information for up to 999 times.

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