Resources and Tips For Harddrive Data Recovery
Data Recovery Techniques
Data recovery is the process of salvaging data from damaged, failed, corrupted, or inaccessible secondary storage media when it cannot be salvaged normally.
Recovery may be required because of physical damage to the storage device or logical damage to the file system.
The exercise of recovering data from physically damaged hardware can involve many techniques. By replacing parts in the hard disk, some damage can be repaired, although this alone may make the disk unusable. To recover every readable bit from the surface, a specialised disk-imaging procedure is used, and once this image is acquired and saved on a reliable medium, the image can be safely analysed for logical damage and could allow for much of the original file system to be reconstructed.
Examples of physical recovery procedures are to remove a damaged PCB, or Printed Circuit Board, and replacing it with a matching PCB from a healthy drive, read/write head assembly with matching parts from a healthy drive, removing the hard disk platters from the original damaged drive and installing them into a healthy drive and very often a combination of all these procedures. Some data recovery companies use highly technical procedures and are not recommended for untrained individuals, as this will most definitely void the manufacturer’s warranty.
Then there is disk imaging, in which the raw image can be used to reconstruct usable data after any logical damage has been repaired. Once complete, the files may be in usable form, although recovery is very often incomplete.
Two common data recovery techniques used in logical damage are called consistency checking and data carving. Even though most logical damage can be repaired or worked around with these two techniques, data recovery software can never guarantee that no data loss will occur. In other words, when two files share the same allocation unit (cross linked), data loss for one of these files is definitely guaranteed.
Consistency checking involves scanning the logical structure of the disk and making sure that is is consistent with its specification.
Data carving is a data recovery technique that allows for data with no file system allocation to be extracted by identifying sectors and clusters belonging to the file. Carving is usually a time and resource intensive procedure.
It is important to note that hard drive manufacturers will not accept any data recovery company without a pass certificate of ISO-5 or better, so be sure to use a reputable company to help you with your problem.