Software In News

Mac 101: Deleting files and erasing drives

22.05.12

There are two ways to think about securing information: Enabling access to information that you want to keep, and disabling access to information you no longer want to keep.  In this post, we will focus on the information Mac users no longer want to keep.  If you are thinking that this is as easy as moving a file to the trash, then emptying the trash, think again.  There are numerous data recovery utilities on the market that can recover lost or deleted files.  And these utilities work because most of us do not know how to securely erase information off of our Macs.  The following are some tips on how you can at least make if very difficult for others to recover your unwanted files.

When you just empty the trash on a Mac, OS X no longer keeps track of where the data associated with the file is stored on the hard drive.  The data is still there, it’s just that the Finder can no longer find it.  As you continue to work and OS X saves new files on your hard drive, OS X could write over parts of your deleted files data with the new files data.  What many data recovery utilities take advantage of is the chance that old data is still there, and has not yet been written over by new data.  When you instead elect to use Secure Empty Trash , OS X does in fact ensure that the old data is written over with new data, which will ensure that the old data is no longer there — think of it like scribbling out a written message on a post-it note.  What is not known for sure is how many times Secure Empty Trash writes over the old file’s data.

Source: GigaOm