As a general rule, when a user formats a hard disk drive some or all of the data is recoverable with special tools. However, users often assume they have completed a low level format when actually they have not and we often find data recoverable after an 'alleged' low level format. Low level formatting writes zeros across the disk, therefore rendering any data unrecoverable. The binary code on your hard drive is represented by either a positive or a negative magnetic represented as a 1 or a zero. A genuine low level format should render any data unrecoverable. Low level formatting is performed directly against the disk sectors, skipping the file system layer and working directly with the underlying storage. A computer is not able to replicate this low level format although it is often assumed that it can.
Lastly, high level formatting (sometimes referred to as 'quick formatting') is used to prepare the drive ready for use. This is not to be confused with partitioning, which makes the device visible to the operating system. The process also creates the new file system. Low level formatting is normally done by the manufacturer of a hard drive to dictate how and where the data is stored on the disk and prepare that disk for initial use. What effect does formatting a hard drive have?
