Why does deleted data stay on a HDD once written, waiting to be overwritten, as opposed to being removed when requesting deletion?
In: 22
In a sense, there is no direct way to ‘remove’ data from a HDD.
You can *read* data, or you can *write* data.
For practical purposes you can consider data to be ‘deleted’ when you can no longer *read* it.
When you create a file, the computer *writes* data to the drive, including a note of what file is there, and a note to not *write* anything else there.
When you tell the computer to “delete” a file, it simply forgets that note of what file is there and the reservation not to *write* over it. Basically, it forgets how to *read* what was there, because that is the easiest way to make the data functionally ‘deleted’.
Now, you could instead *write* over the data with new data (like all 0s or all 1s). That would also make it unreadable. However that would take more time and electricity, and slow down your computer for uually no benefit, so we don’t bother with that. [If you need to keep secrets, this extra time and electricity might be worthwhile.]
Latest Answers