However, if the hard drive can be repaired and a full image or clone created, then the logical file structure can be rebuilt in most instances. The most common data recovery scenario involves an operating system failure, logical failure of storage devices, accidental damage or deletion, malfunction of a storage device, etc. in which case the ultimate goal is simply to copy all important files from the damaged media to another new drive. In computing, data recovery is a process of salvaging inaccessible, lost, corrupted, damaged or formatted data from secondary storage, removable media or files, when the data stored in them cannot be accessed in a normal way.
Another scenario involves a drive-level failure, such as a compromised file system or drive partition, or a hard disk drive failure. In any of these cases, the data is not easily read from the media devices. Recovery may be required due to physical damage to the storage devices or logical damage to the file system that prevents it from being mounted by the host operating system. Physical damage to a hard drive, even in cases where a head crash has occurred, does not necessarily mean there will be permanent loss of data. Of course there are exceptions to this, such as cases where severe damage to the hard drive platters may have occurred.
While this may work in rare circumstances on hard disk drives manufactured before 2003, it will not work on newer drives. When these dust particles get caught between the read/write heads and the platter, they can cause new head crashes that further damage the platter and thus compromise the recovery process. The sector lists are also stored on various chips attached to the PCB, and they are unique to each hard disk drive. If the data on the PCB do not match what is stored on the platter, then the drive will not calibrate properly. Replacement boards often need this information to effectively recover all of the data. In most cases the drive heads will click because they are unable to find the data matching what is stored on the PCB. Electronics boards of modern drives usually contain drive-specific adaptation data and other information required to properly access data on the drive.