Elementary knowledge of data recovery

Ⅰ.Elementary knowledge of data recovery
1.Connotation of data
Connotation of data is comprehensive, it includes not only multi-media files such as data
documents, images, voices that stored in file system or data base, but also hardware information,
network addresses and network services, which are used to deposit and manage those information.
2.The essence of data recovery
Data recovery means retrieving lost, deleted, unusable or inaccessible data that lost for various
reasons.
Data recovery not only restores lost files but also recovers corrupted data.
On the basis of different lost reason, we can adopt different data recovery methods. There are
software and hardware reasons that cause data loss, while we can recover data by software and
hardware ways.
Being different from prevention and backup, data recovery is the remedial measure. The best way
to insure the security of your data is prevention and backup regularly. To operate and use your data
according to the normative steps, you can reduce the danger of data loss to the lowest.
3.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.