Hard Drive Recovery: Logical and Physical

Hard drive recovery is the process of extracting dataservice for of lost data is carried out by Data
with the help of software utilities or disk internals levelRecovery experts with rich industrial experience and
operations plus software tools from logically orexposure to the hard disk internals. Such recovery
physically corrupted hard drive. The best practice is toprocedures often deal with dismantling the hard drive
create a disk image before carrying out any recovery.and repairing or even replacing certain components like
A disk image is an exact copy of a hard drive or anthe read/write head, actuator arm if they have failed.
affected partition/volume. It is created to avoid anyThe Hard Drive Recovery is performed under
data loss during the recovery procedure. We shouldsterilized environment of Clean rooms. The lab
always maintain an updated data backup on aenvironment of Clean rooms offer controlled
secondary storage device like an external hard drivetemperature, pressure, humidity and no dust particles to
to avoid any recovery requirements. If we have all theensure maximum protection to hard disk internals.
data backed up, we can simply perform a cleanThe data that we save in the hard drive actually gets
reinstall and restore the data as per our last directorystored on the platters. The less these platters are the
structure. In addition to this we should use hard driveseasier it is to recover the lost data. In case, a platter
with highest MTBF (Mean Time Between Failure) ratinghas physically failed has developed physical bad
and S.M.A.R.T (Self-Monitoring, Analysis and Reportingsectors we cannot retrieve our lost data from that
Technology) support. We need to enable theplatter and the area affected by physical bad sectors
S.M.A.R.T option in system BIOS (Basic Input Outputwill become unavailable for recovery due to
System) to make it check the hard drive for anyunreadable media. Such physical bad sectors cannot
physical issues and proactively inform us.be repaired or removed like the logical bad sectors.
A hard drive is divided into various sub-parts. They canHard drives offer large storage capacity and are very
be broadly divided as moving and non-movingcost effective as compared to other storage media.
components. The moving components are: SpindleToday hard drives are available in the market up to 2
Motor and Spindle, Read/Write Head, Actuator Arm,TB of storage. When we delete data in any operating
Head Actuator and Platters. The non-movingsystem like Microsoft Windows, Apple Mac OS or
components are: 1.) Hard Disk Controller 2.) Head/DiskLinux, the files don't get deleted in actual. It is just the
Assembly 3.) PCB (Printed Circuit Board) 4.) Inputfile reference that gets removed by the operating
Output Connector etc.system. In other words, the files still remain on the hard
The Hard drive Recovery can be done by followingdrive though we cannot access them using the
these two approaches as per logical or physical driveoperating system. The same is true in case of lost or
failure:i.) Hard Drive Recovery Software: These arecorrupted data but the corrupted data files need to be
utilities that are developed based on file systemrepaired as well.
structure information to enable the software to find theThe partition or volume loss also follows the same rule
files, file signature information to recognize the filethat is the data still resides in the partitions or volumes
header and footer and advanced scanning algorithmsbut we cannot access them. The common reasons
to efficiently scan the hard drive. A home user canbehind such errors are system software conflicts,
easily use these software to scan his hard drive aftererroneous deletion, operating system warning related
data loss. Some data recovery software also offerto partition health, virus infection etc. If we face any of
bootable media like CD or DVD to boot the systemthe above issues and the hard drive data becomes
from them in case the system is not able to boot. Weinaccessible, we should not use the hard drive any
need to attach an external hard drive (USB/Firewire:further other than Data Recovery from it in order to
IEEE 1394) or flash drive (USB). We can boot theavoid any disk overwriting. After the lost files get
system using the bootable media and scan the hardreplaced by any erroneous user operations like
drive. We can even preview the lost files in goodoverwriting the drive with some new files like by a
quality data recovery software and then save the filespaste operation, it becomes impossible to recover the
in the external hard drive or flash drive.ii.) Hard Drivefiles as their start and end points get changed by the
Recovery Service:  The Hard Drive Recoverynew files.