Then it goes back and fills each of these sectors with zeroes, effectively returning these sectors to what appears to be an unused condition. In simple terms, it looks for all the sectors on the drive where the flag is down, and creates it's own file table of where they are located on the drive. This is where a drive wiping utility comes in. Also, defragmenting your drive can overwrite quite a few of these sectors as well, the thing is, you cannot be sure which sectors containing old data were overwritten and which were was not. So keep this in mind, when you delete a file in Windows, it does not completely disappear until all the sectors used to store it get overwritten by a new file. If the flag is down, it is available for a new write operation, and then one of two things happen: either the old data that was previously stored there gets overwritten by new data, or a previously empty sector gets written to for the first time.

When the flag is up, it is in use, and cannot be used to write new data. Think of each sector as a mailbox with a flag on it. All you are doing is changing a file table that the operating system uses to keep track of where the individual pieces of data are stored on the drive, and these little storage units are called sectors. This is because when you delete a file in Windows, the data still physically remains on the drive. It can exist in one of two conditions: either it was previously written to and used to store data, or it was never used and contains no data.

I'll try to answer your four questions a simply as I can.ġ.) As long as you deleted your browser history prior to doing a drive wipe, it's gone.Ģ.) As long as you deleted any other files prior to doing a drive wipe, they are gone.ģ.) A bit more tricky - Free space refers to all the space that can be used to perform new write operations to your drive. It's very difficult to describe how a hard drive works without getting technical, and I certainly make no claim to knowing anything more than the basics.

Drive wiper