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Flubflow · 02-10-2004, 08:36

Yes. When you delete a file it does not actually get deleted as such. It merely tells the FAT (file allocation table) that the space occupied that file is now free to be overwritten and you just don't see the file anymore. The deleted file may eventually be overwritten or partly overwritten over a period of hard disk use. With undelete utilties you can often retrieve entire intact files especially if they have only recently been deleted.

These "Eraser" wiping utilities will overwrite the deleted files with zeros or whatever so that deleted files can not be recovered.

Incidentaly, the more secure "government wipe" overwrites deleted space by writing 1's then 0's several times then writes another value and then all that can be repeated a few times (presumably to reduce the chance of any slight residual magnetic charge adjacent to the track holding the original data - which could be read in a laboratory situation by specialist spooks).

Basically, a good defrag (I like Nortons) where you also defrag the unused space too is all you really need to do keep you system running smooth. However, if you selling your computer then you'd would probably want to use proper wipe utility to ensure there is no personal data that could be unerased later.

02-10-2004, 08:36	#2
Flubflow Inactive Join Date: Nov 2003 Location: Teesside Posts: 1,566	Re: Erasing unused disk space ??? Yes. When you delete a file it does not actually get deleted as such. It merely tells the FAT (file allocation table) that the space occupied that file is now free to be overwritten and you just don't see the file anymore. The deleted file may eventually be overwritten or partly overwritten over a period of hard disk use. With undelete utilties you can often retrieve entire intact files especially if they have only recently been deleted. These "Eraser" wiping utilities will overwrite the deleted files with zeros or whatever so that deleted files can not be recovered. Incidentaly, the more secure "government wipe" overwrites deleted space by writing 1's then 0's several times then writes another value and then all that can be repeated a few times (presumably to reduce the chance of any slight residual magnetic charge adjacent to the track holding the original data - which could be read in a laboratory situation by specialist spooks). Basically, a good defrag (I like Nortons) where you also defrag the unused space too is all you really need to do keep you system running smooth. However, if you selling your computer then you'd would probably want to use proper wipe utility to ensure there is no personal data that could be unerased later.