Some Facts About Deleted Files

When we delete a thing it usually doesn't exist anymore. It is deleted. We rarely expect to be able to undelete anything. But computers and all other digital equipment behaves differently. It is not possible to "normally" delete digital data. You can only change it. Of course, when you change the original data you have deleted the original information. But the data is still there, only the information was deleted.

This fact can come handy when we accidentally delete some file. The first step of deleting a file is to move it to the recycle bin. From here it can easily be restored back. But when we empty the recycle bin the file is lost. But we can still get it back because it was not deleted, it was only marked as invisible (deleted). It is possible to undelete or recover files even if they were removed from the trash can. However, this possibility lasts until some other file overwrites the original deleted file.

Because of the way how operating systems delete files many companies have problems. Whenever they would like to get rid of old computers they can not simply dump them. All the hard drives contain files. There might be sensitive data or even confidential files, passwords or credit card numbers. Therefore, before each computer leaves a company, every hard drive must be erased. To properly erase the hard drive and to actually delete all the files and to prevent data recovery, all the data on the drive must be overwritten many times. One pass is not enough because of the way how hard drive writing heads write new data on the drive. With some advanced technique it would be possible to recover once overwritten data. However, such equipment is expensive and not available to everyone. But for intelligence agencies this is not a problem, so adequate measures need to be taken.

Hard drive data recovery is possible but you need tools and knowledge. Because of many reasons computer users lose their data there are many data recovery companies. They can recover data from damaged or broken hard drives, failed digital cameras, RAID systems or any other digital media.