Almost everyone who has ever used a computer has erased a file that they later wanted to bring back. The less fortunate may have also had the experience of losing an entire hard drive. Luckily, hard disk recovery allows for lost data to be recovered.
Hard disk recovery is possible because of data remanence, which means that some data continues to exist on the hard drive even after it has been deleted. While data remanence is beneficial to hard disk recovery, there is also a downside; that is, data remanence is one of the most convenient tools used in cyber-espionage. That's why computer security experts tell you that simply erasing a file doesn't always completely delete it.
A hard drive contains a series of hard disks that rotate rapidly. These disks are coated with magnetic particles, similar to a magnetic recording tape. The hard disk is actually very durable, and good maintenance will ensure long life. If it is not exposed to extreme temperatures, and does not suffer any physical damage, it can easily last for ten years. However, hard disks do have several moving parts, and can become damaged or wear out.
Hard disk recovery reconstructs lost files, regardless of whether they were deleted accidentally or are inaccessible due to a crashed hard drive. In some circumstances, the hard disk may become inaccessible because of a hardware problem. The actuator arm, a small mechanical arm that moves back and forth across the disk, may have suffered a mechanical error. In this event, the data is not lost at all, but is just inaccessible due to this mechanical problem. Similarly, the circuit board may develop flaws, which may make the hard disk inoperable. If there are strange noises, or no noise at all, the cause is likely mechanical, and a technician will have to disassemble the hard drive to repair the problem. In some cases, the mechanical problem may cause the drive itself to become damaged, which may directly affect the data. Alternatively, data loss may occur due to a software problem.
Taking a little preventive action can help prevent the need for hard disk recovery. When files become fragmented, they are stored in multiple clusters on the hard drive, which makes the computer take more time to read it. A drive with a lot of fragmentation will be harder to recover in the event of a crash. Therefore, it is recommended to regularly defrag your hard drive.
When a file is deleted, the operating system marks the file name with a character that informs the computer that it has been deleted. The deleted data is actually still on the drive until the file system overwrites it, but the operating system can no longer access it. The process of hard disk recovery finds the data that the operating system is unaware of, but still exists in individual clusters on the hard drive. However, clusters that have become corrupted or physically damaged cannot be recovered. In these cases, hard disk recovery has a greater likelihood of success if it is attempted immediately after the failure so as not to give the sectors with missing data an opportunity to be overwritten. A professional hard disk recovery service will not work on the hard drive itself, but will instead make a sector copy of the hard drive and work from that.