Incredible data recovery-how to recover overwritten data
Can the data being overwritten be recovered?
If there is anything unclear about the data recovery community at home and abroad, it is the accepted problem that the coverage of data recovery is the first. So can the overwritten data be recovered? For magnetic storage media alone, the possibility is very high. Why do you say that, there is no absolute thing, the number of coverage determines the direct difficulty of recovery. Before unraveling the mystery, you can recall the previous experience of using recorders and video recorders. If you have recorded audio or video tapes, if you do not wash them cleanly, there will be a lot of noise interference when you record them. Is there such a problem with hard disk storage? I think hard disk manufacturers must have encountered this problem in the process of developing hard disks, but they solved it by accurately controlling the positioning of magnetic head read and write and track tracking. Later the data is completely Overwrite the previous data, the interference is gone, the hard disk is perfect!
Where is the entry point for overwriting data recovery?
However, everything is afraid of being serious. This is what Chairman Mao said and cannot be wrong. After all, the positioning of the hard disk head is inaccurate, and this is the leak. The magnetic head can not always be accurately positioned to the ideal position, just like you drive to work, although you always take the same road, but each rut can not completely coincide. Therefore, the data written by the magnetic head on the same track cannot be completely covered. However, this error is too small, the hard disk circuit can ignore these tiny clutter interferences, so the user sees the perfect coverage of the data. The master of data recovery is also in vain. Look at the picture below. The process of recording data by the magnetic head is not to draw a perfect concentric circle on the surface of the disc. He has burrs!
Figure 1 Hard disk track imaging
The loophole is coming! The solution is all come up with. Since the hard disk has this loophole, someone must use it. At least the hard disk manufacturer can do it. Congratulations, you guessed it! If the manufacturer uses the technology to detect the surface morphology of the disk during the production process of the hard disk, it is to see the tiny structure on the surface of the disk, whether there is any damage or the like, you can see more after The second "rolling", the remaining data information. But why are manufacturers reluctant to let the outside world know that they can do this? If you think about it, if the hard disk manufacturer tells you that the hard disk he produced, the data covered can also be recovered, which is equivalent to indirectly admitting that his hard disk has quality problems! Recall the story of the tape mentioned earlier. But this data recovery technology can certainly be used in the field of fighting crime, disaster rescue and other benefits for mankind.
Dass Technology's solution to data recovery after overwriting
To return to the truth, it is feasible to cover the recovery of data, but it needs a more alternative approach. The Darth data recovery engineer found that when the hard disk is in normal use, it is the conversion of electromagnetic signals, and the host end obtains a digital electrical signal. In order to track the covered data, this electrical signal is no longer available, and it is necessary to obtain the appearance of the hard disk surface data after coverage Information, in layman's terms, is to take a picture of the surface of the disc to obtain information on the magnetization of the surface of the disc, and track the covered data based on the magnetization information.
So how to "photograph" the surface of the disc? Is it possible to use a digital camera? No, it is useless to use the best SLR, the optical signal and the magnetic signal are not at all connected. In the past, it was rumored that the use of a laser to read a disc or something was all anecdotal. Need to get a sharp tool for magnetic signals. So, MFM-Magnetic Force Microscope is here! You can get a clear image of the disk by scanning and sampling the surface of the disk with a probe, see Figure 2
Figure 2 Magnetic imaging of the surface of the hard disk
Look, see, how clear! The disk where the data was written is like a paddy field overlooking from a height. From the middle of the small lattices, there are traces of "crushed" read and written by the magnetic head. This is exactly the traces left after the data is overwritten. Analyzing the reasons for the generation of these traces can gradually analyze the data before the coverage, but this It's just the first step of the Long March. It's useless to see the data. You need to combine these data into meaningful data, otherwise it will be a bunch of garbled characters, and there will be nothing to get back.
In fact, it is of far-reaching significance to study the coverage of data recovery. Although it cannot be recovered from the file system level, there are still profound and thoughtful solutions from the physical level.
About Darth Data Recovery Center:
Darth Technology is committed to the research and development of data recovery technology. Darth Data Recovery was established in Zhongguancun in August 2007. As a well-known brand in the data recovery industry, it has technological advantages that lead the country and even Asia! Recover software, equipment research and development, data recovery training, data recovery training room construction, etc., to provide customers with comprehensive solutions.
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