the Logic Behind Data Recovery Software

What is the logic behind data recovery software to recover deleted data from memory card and hard disk?

Data recovery software can recover files from formatted hard drives, emptied recycle bins, unreadable SD cards...People may wonder how the recovery is done and why it can be done. 

To understand the logic behind data recovery, let’s first take a look at what data recovery software can and cannot do. Let's take H Data Recovery Software as an example.


H Data Recovery can recover permanently deleted files; recover from quick formatted disks; recover from crash partitions; recover personal data from system reset; recover photos from unreadable camera memory cards…It can handle most of the data loss situations but there are some exceptions. 

Severe physical damage to the storage media can cause permanent and unrecoverable data loss, such as scattered hard disk drive platters or burnt NAND flash memories. File data are essentially combinations of ones and zeros. These data are represented differently depending on the storage media. For HDDs (Hard Disk Drives), data are represented by magnetized and demagnetized tiny magnetic domains, while for SSDs (Solid State Drives) by the presence and absence of electrons. If the storage media is physically damaged, it means these bits of data are physically damaged. This is beyond the effort of any software.

Aside from physical damage, overwritten files can hardly be recovered either. Every data recovery specialist would recommend you to avoid writing new data into the storage device in the event of data loss. Overwriting includes using file shredding software to shred files; using drive cleaning software such as DBAN to wipe entire drives; overwriting by putting new data upon old file locations...File shredding software and drive cleaning software is designed with security in mind. The sole purpose is to eliminate the risk of security and privacy breach posed by unauthorized recovery.

Simply put, data recovery software can recover files that still exist in their original form as data but are simply inaccessible due to file system operation such as deletion or system error. 

How Data Recovery Works

Data recovery software takes advantage of the mechanism of deletion. When we delete a file, the file system only removes the address pointer to that file. But the file itself as raw data is still there. The computer just marks it as “deleted, can be overwritten”. If we put new files in, the computer may notice the newly freed space and cram the new file there. By doing so, the data of the old file, which is a complex combination of ones and zeros, will be re-arranged to form the new file data. That’s why overwritten files can hardly be recovered.

The same goes to quick format. When we quick format a memory card or hard disk, the file system only clears the address table to all files. The operating system will not locate any files without their index so when you look at the hard drive you would not see any data and assume the drive is erased. In fact, the files as raw data are still there but they are no longer exist as files. They are hidden from users and will be freely overwritten.

Why won't the system just truly delete them right away? As mentioned above, to permanently remove a file requires the file to be overwritten. That means each time you delete a file, the system will overwrite the file with zeros or ones. This is time-consuming and inefficient.

As long as your lost files are not overwritten or physically destroyed, professional data recovery software such as H Data Recovery will be sufficient to scan, search and reconstitute these files and restore them.

Above is the basic logic behind data recovery software. There are many different scenarios where you would unfortunately lose data. Select your solution accordingly and with caution. The best precaution, of course, would be the good habit of backing up your important data and store them safely away.