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 files types and getting a possible list hundred thousand file 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 apologies, 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 a standard computer usage, when hundreds of files are wrote to the disk, deleted and another ones are wrote again. Files became fragmented by file system. Files that are larger than a available piece of free space on the disk is split into several smaller pieces that are fit between other files.
Knowing basics of data storage obviously there is two basic approaches for data recovery:
- File carving technique that focuses on recovering files by it's internal structures types of data or signatures used to structure user data inside file.
- File system recovery on the opposite, doesn't operate contents of files and intends to reconstruct damaged file system in it's original state.
Diskinternals VMFS Recovery implements both approaches, however they are separated because of lower quality of file carving compared to file system recovery. Low results of file carving (we call it Power Search) happens exactly because of fragmentation of data on the disk. Usually it's impossible to determine if file has reached it's end, if it's fragmented or not, if there is another piece of file somewhere on the disk or not.
By default standard folder tree is displayed, which is a result of file system recovery algorithm. Results of Power Search are placed into “Recovered Files” virtual folder and are sorted by file type.
To recover 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.