NAND is a classification of memory devices (‘chips’) which are used in USB memory keys, SD or microSD cards and SSD (solid state drives).
The failures that can occur fall broadly into one of three categories
Electronic component failure
The internal circuit in many solid-state memory devices includes a number of electronic components which are present to facilitate the writing of data to a memory microchip via a controller chip. The ancillary components include a crystal oscillator and a series of capacitors and resistors required to support the transmission and reception of data through the USB/SATA interface.
If a component in the supporting circuitry (other than the memory or controller microchips) fails, this can usually be repaired or replaced so as to get the device working on a temporary basis for enough time to complete a full recovery of data.
However, many newer devices use monolithic construction where all of the micro-components are encapsulated in a single black resin block. These particular types of devices are not serviceable at component level.
Resolvable service area corruption
A service area fault involves corruption of a critical service area module which renders the hard drive in a state where: –
- It cannot initialise
- It cannot address sector content
- The address translations (between logical sector number and physical data location) cannot be made.
For selective SSD’s. solutions exist to overcome these issues, and the library of available solutions is constantly growing. However, if your device does not have a solution developed by our systems vendor, then the only remaining option is to perform a direct extraction of data from the memory microchips contained within your device (called a ‘chip-off’ process).
Unresolvable electronic/service area corruption requiring ‘chip-off’
This method involves obtaining a raw dump of the data from the microchip(s), followed by complex re- translation of the dump to a logical image in order to obtain the original data structure and files.
For SSD’s, direct memory connection is achieved by de-soldering the memory components from the SSD and interfacing directly to the contacts of the microchips using specialist adapters.
For modern SD and microSD cards, direct memory connection involves connection to masked service pins (under the black resin coating). The pin layout may already be known or may need to be determined separately.