A Single Overwrite Is All You Need to Ensure Permanent Data Deletion
By Jenny • Jan 20th, 2009 • Category: Mobile Computing Accessory NewsA general misconception that resides in the minds of PC users is that if the data is to be deleted from a HDD (hard disk drive) permanently then it has to be overwritten many times and that too using different patterns. But the fact is that a single quality overwrite can do this job perfectly. All the major data recovery companies now admit this but still the data shredder software programmes have the option of shredding the data up to 35 times. However, this is a complete waste of time. The only benefit of this is that the home user gets a psychological satisfaction and nothing else.
If a drive is overwritten with zeros only once, then it’s a complete secure deletion and the data cannot be retrieved. According to a research conducted by the forensics expert Craig Wright, when the data is deleted off a hard drive using single overwrite it’s practically impossible to remake the bits that way again. Even if a hacker knows the exact location of a single bit then the probability of reconstructing the data correctly is 56 percent. Further to recover a byte is even more tedious as it requires adjusting the HDD head at the appropriate position eight times repeatedly. The probability of succeeding in this is just 0.97 percent. This is essentially applies to every kind of hard disk, including models such as the Western Digital Caviar Green SATA 1TB drive, since Craig Wright has conducted his study using several hard disks of different make, size, storage capacity and age.
The final conclusion is it’s more important to completely overwrite the data sector by sector instead of focusing on the number of overwrites.
Tags for this article: mobile, drive, samsung r720
