Elementary knowledge of data recovery - The scope of data recovery

There are so many forms and phenomenon on data problem, we can divide the objects or scope of data recovery according to different symptoms.

System problem
The main symptom is that you cannot enter the system or the system is abnormal or computer closes down. There are complex reasons for this, thus we need adopt different processing methods. Reasons for this symptom may be the key file of system is lost or corrupted, there is some bad track on hard disk, the hard disk is damaged, MBR or DBR is lost, or the CMOS setting is incorrect and so on.

Bad track of hard disk
There are logic and physical bad track. Logic bad track is mainly caused by incorrect operation, and it can be restored by software. While physical bad track is caused by physical damage, which is real damage, we can restore it by changing the partition or sector. When there is physical bad track, you'd better backup your data for fear that the data can not be used any more because of the bad track.

Partition problem
If partition can not be identified and accessed, or partition is identified as unformatted, partition recovery tools such as Partition Table Doctor can be used to recover data.

Files loss
If files are lost because of deletion, format or Ghost clone error, files restoring tools such as Data Recovery Wizard can be used to recover data.

Password loss
If files, system password, database or account is lost, some special decryption tools that correspond to certain data form such as Word, Winzip can be used.

Files repair
For some reasons, some files can not be accessed or used, or the contents are full of troubled characters, the contents are changed so as they can not be read. In this condition, some special files restoring tools can be tried to restore the files.