by Don_HH2K » Thu 25 Mar, 2010 10:24 am
Internet Explorer keeps its history data in a file called [tt]index.dat[/tt], which is preallocated and therefore doesn't move around on the disk.
In terms of how hard drives work, this means that the bits are being written in the exact same spot on the disk platters, over and over. The reason that you can often undelete files is that the space freed upon deletion doesn't always get reused immediately, so sometimes there are file fragments laying around on the drive with no links pointing to them. The difference with a preallocated file is that the file never gets deleted, so the data is directly being overwritten each time.
In your particular case (November to March and a default archive span of 20 days), that works out to around six overwrites. By comparison, standards set by organizations such as the British government and the US Army "securely" wipe data using three overwrites.
(Sorry to get technical, but I couldn't figure out how to phrase it otherwise.)
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