On a mechanical hard drive, Data Recovery Services is often possible: there is a physical trace of the Data Recovery Services written. There are many services or companies that offer this type of service. Thus, it is enough to repair the defective mechanical components and/or to use forensic software/device. For SSDs, data recovery or data recovery is much more complex.
On an SSD, as there is not necessarily the slightest link between the logical and physical organization of the Data Recovery Services, this operation is much more complex or even impossible in certain cases.
The process for recovering Twitter data from a faulty SSD is always the same, whatever the origin of the fault (controller fault, circuit break, etc.) :
- It is necessary to de solder the memory chips that compose it to read the stored data individually, this requires specific and precision equipment (soldering station, specific reader, etc.).
- It is then necessary to reconstruct the data, this is the most laborious and complex part. Indeed on an SSD, the data is organized in a rather specific way.
First, all bits are, by default, 1, so to minimize the number of writes/erases, and the number of 1s, in chips, very often manufacturers choose to apply an XOR function to the data incoming. The problem being that the XOR function is difficult to reverse in addition to being difficult to detect. In addition to this the data can be organized in various ways, more or less complex.
Take, for example , next-generation internal interlacing . This way of organizing the data distributes the pages per block, i.e. a logical volume of X pages will be written on (assume) two blocks, we will then find the even pages in the even blocks and the odd pages in odd blocks.