Data Recovery methods: advantages and drawbacks

Often people ask a question like: Is it possible to specify a custom file type or extension? I need to recover only *.edb and *.dfc file types without having to bring all the other file types and getting a possible list hundred thousand files that I don't need.

Shortly the answer is: Yes, this is possible.

However the question isn't really correct. Please let me explain. I must apologize, it requires several terms I've explained below.

All data on the disk are stored in two basic layers:

• Files – where specific data is organized as intended by file type developer;
  
  
• File system – which was developed to store not user data, but files as a minimal chunk of information.

During standard computer usage, hundreds of files are written to the disk, deleted and other ones are written again. Files became fragmented by the file system. Files that are larger than an available piece of free space on the disk are split into several smaller pieces that fit between other files.

Knowing the basics of data storage obviously there are two basic approaches for data recovery:

• File carving technique that focuses on recovering files by its internal structures types of data or signatures used to structure user data inside a file.
  
  
• File system recovery on the opposite, doesn't operate the contents of files and intends to reconstruct the damaged file system in its original state.

Diskinternals VMFS Recovery™ implements both approaches, however, they are separated because of the lower quality of file carving compared to file system recovery. Low results of file carving (we call it Power Search) happen exactly because of the fragmentation of data on the disk. Usually, it's impossible to determine if the file has reached its end. Suppose it's fragmented or not. If there is another piece of the file somewhere on the disk or not.

By default, a standard folder tree is displayed, which is a result of the file system recovery algorithm. Results of Power Search are placed into the “Recovered by Signatures” virtual folder (formerly known as "Recovered Files") and are sorted by file type.

To recover a specific file type, which is not supported yet by our Power Search technology, our developers need to investigate undamaged samples of this specific file type. This is required to “learn” software to detect this specific file type.

Such tuning is made free of charge by request of our customers. We don't require Diskinternals VMFS Recovery™ license to provide such support.