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 recover deleted files 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 retrieve pictures 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.
 
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 recover deleted photos on Mac deletion, format or Ghost clone error, files restoring tools such as Data
Recovery Wizard can be used to recover data.
Password loss Data Recovery E-Book V1.5 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.
4.The principle of data recovery  
Data recovery is a process of finding and recovering data, in which there may be some risk, for no
all  situations  can  be  anticipated  or  prearranged. It  means  maybe  there  will  be  some  unexpected
things happen. So you need reduce the danger in data recovery to the lowest:
 
Backup all the data in your hard disk
Prevent the equipment from being damaged again
Don’t write anything to the device on which you want to recover data  
Try to get detailed information on how the data lost and the losing process
Backup the data recovered in time.