Flash memory SSD, SD, MMC, etc. Restoration and repair
Recently, various devices using flash-memory have been used to store data. This is a compact, fast and not afraid of shock device.
But from the point of storing and reading information on flash memory there are four main problems. :
- low write speed in the cell;
- limited number of write cycles per cell (for mlc: 10,000 times, for slc: 100,000 times);
- reducing the time of static data storage depending on the number of write cycles;
- Charge runoff over time (∼2 year).
To partially eliminate these drawbacks, we have to allocate part of the flash memory for service data and use a special controller. This controller, using service data, controls the number of entries in the memory cell, the accuracy of user data, and also implements a complex block mode of writing and reading memory cells to increase speed. Such work ensures the integrity and reliability of user data. But there are times when the service data itself is violated. In this case, a violation of translation occurs (violation of the order of the readable memory cells). With such faults, access to the logical structure of flash devices is violated - the device either does not appear, or shows the wrong amount or has access to it only in read mode.
Repair of such drives is possible if the data that is on the faulty device is not important. Features of repair and software for this can be found on the website: Utilities and firmware (link changed for stupid;) ... I have no relation to the site)
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But if you need to recover data, then you will encounter a completely non-trivial task, comparable in complexity to restoring such complex devices as RAID arrays. During data recovery from a faulty device, a flash memory chip is extracted, cells with data are read from it and with the help of special programs, data is restored.
In what other cases do you have to resort to help recovering data from flash devices?
We also have to resort to the data recovery operation described above for physical (electrical) damage to the flash device controller, as well as forgeries from Southeast Asia, which usually imitate flash devices with more memory than they really are. Such devices usually work normally until the volume of recorded data exceeds the real volume of the device.
But from the point of storing and reading information on flash memory there are four main problems. :
- low write speed in the cell;
- limited number of write cycles per cell (for mlc: 10,000 times, for slc: 100,000 times);
- reducing the time of static data storage depending on the number of write cycles;
- Charge runoff over time (∼2 year).
To partially eliminate these drawbacks, we have to allocate part of the flash memory for service data and use a special controller. This controller, using service data, controls the number of entries in the memory cell, the accuracy of user data, and also implements a complex block mode of writing and reading memory cells to increase speed. Such work ensures the integrity and reliability of user data. But there are times when the service data itself is violated. In this case, a violation of translation occurs (violation of the order of the readable memory cells). With such faults, access to the logical structure of flash devices is violated - the device either does not appear, or shows the wrong amount or has access to it only in read mode.
Repair of such drives is possible if the data that is on the faulty device is not important. Features of repair and software for this can be found on the website: Utilities and firmware (link changed for stupid;) ... I have no relation to the site)
')
But if you need to recover data, then you will encounter a completely non-trivial task, comparable in complexity to restoring such complex devices as RAID arrays. During data recovery from a faulty device, a flash memory chip is extracted, cells with data are read from it and with the help of special programs, data is restored.
In what other cases do you have to resort to help recovering data from flash devices?
We also have to resort to the data recovery operation described above for physical (electrical) damage to the flash device controller, as well as forgeries from Southeast Asia, which usually imitate flash devices with more memory than they really are. Such devices usually work normally until the volume of recorded data exceeds the real volume of the device.
Source: https://habr.com/ru/post/109057/
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