Q:
A: There are a few pro's to wiping free space on a computer: 1) When you delete a file, leaving some free space behind, the file isn't actually erased - only the information pointing to it is deleted so the computer doesn't see it anymore and only sees blank space ready for reuse. Obviously, this could be a security risk as it is very easy to restore these files from the hard disk even though they've been deleted. Wiping the free space works by writing a pattern of data over free space a number of times so that any file remnants that are left behind are obliterated and this makes it harder if not impossible for deleted files to be restored. 2) From the minute a hard drive is manufactured, it starts to fail but this is entirely normal. Through use the failure is monitored by the hard drive's internal systems and areas of the disk that fail to meet the performance criteria are flagged as bad sectors. A certain proportion of bad sectors are safe before the computer will alert you to the problem. But what if your computer never accesses part of the hard drive that is bad and so doesn't know about it? Free space wiping will help the hard drive detect bad sectors and flag them up as unusable. The main downside of free space wiping is that it can be extremely time consuming on large drives. With this in mind, I've never found that the amount of time was worth spending for any of the benefits above. If security is your main concern then it may well be your only choice. (on a side note - if security is your aim, then an alternative might be file shredding which securely deletes a file, then overwrites the space where it lived on the hard drive - the problem with this approach is that most applications will use a temporary space on the hard drive called a cache when you are working on a file to keep a working copy of it. When you close the application, this cache is deleted, but it is not shredded and so any information in the cache about the file that was being used by the application can be recovered. Free space wiping is the best method to get around this.)