Data corruption is a common phenomenon, for ages computer administrators are battling to suppress this demon. Data recovery, is the angel guarding the gates to data loss. Data loss is a result of data corruption due to Hardware failure or software failure. Hardware failure, as the name suggests it is due to malfunction of the hard drive. Malfunction or hardware failures occur as the hard drive has moving parts. Moving parts always leads to wear and tear even when the most sophisticated technology is used.
Software failure can be due to a lot of reasons, like bad TOC (Table of contents). Table of contents is the table created and used by the operating system. TOC has the starting address of all the files on the disk. TOC of a partition or a hard drive can be recreated in much less time. Software failures also occur due to file system corruption. The file system is the format in which the data is written on to the disk. Different File systems have different advantages. For example NTFS, is useful when the system is connected to a network where more no of access for read and write are requested via the local or remote networks. It is also useful for providing good security by restricting the read and write based on the user level abstraction. Likewise FAT32, is useful for small partition it also put less stress on the hard disk ensuring more life time. Reconstructing a corrupted files system is possible but is a time consuming process. The reconstruction is done by raw scanning for clusters for data. Data recovery can be done by using freeware like recuva, it work on all windows platform for multiplatform you should try using PhotoRec. The above stated software just read the disk for data which can be recovered if deleted or formatted by mistake.