Solid state devices (SSD) are based on new technologies, which are not fully understood, as they are the exclusive property of their manufacturers and generally are not disclosed. These technologies are complex and constantly evolving, creating a challenge for the SSD data recovery software. These include encryption, TRIM and over-provisioning. To note, these technologies present an extra challenge to recover files of SSD likewise to recover files from SD card with specific tools.
How does an SSD work?
Many SSDs use encryption by default. Its purpose is to protect the data stored in the device. The encryption mechanism that is used can be based on software or hardware. To access the data, the encryption requests specific credentials that the user must know. Otherwise, you may lose access to the data. For example, Microsoft uses BitLocker, which allows full disk encryption, and ScanDisk memory cards contain its patented Secure Access Vault.
TRIM cleans pages with invalid data. When TRIM is enabled on the SSD, this operation is performed in the background by the garbage collector. TRIM is described in the SATA protocol as having three different types: non-deterministic, deterministic reading after TRIM (DRAT), and deterministic zeros after TRIM (DZAT). Only DZAT performs a complete and permanent cleaning, replacing the content with zeros after the removal. However, as the reallocation of units is constantly done to release addresses, the data can remain intact, and even if it tells you that they have been deleted. Microsoft provides a utility called fsutil, which can be used to verify whether the TRIM mechanism is automatically enabled or not. This utility is available from Windows 7.
Over-provisioning is a mechanism designed to increase the service life of SSD. It simply means adding some additional blocks that are reserved by the controller and can be used to replace those that fail. For example, a device that claims to contain 120 GB may actually have more storage space available.
How do these technologies affect the recovery of SSD data?
Encryption makes it necessary to have credentials. Because of this, experts advise keeping a copy of them in a safe place. If they were used recently, these credentials can be available in RAM and can be recovered with dedicated software.
TRIM creates serious obstacles, especially if done automatically. In this particular case, even if you turn off the computer after the command has been issued by the operating system, this will not stop its execution. Once the computer is turned on again, the operating system will continue executing this operation. This is especially important since Microsoft only uses DZAT in Windows. In other cases, some data can be recovered with specific hardware SSD data recovery tools. Over-provisioning can affect the recovery of SSD data, since some storage spaces may not be accounted for as available or used.
What to do in case of data loss?
The most important step is to stop using the device and keep it in the best possible conditions. The second step is to make an image of the device and try to recover the lost data of this copy. In this way, the original source will not be affected by the recovery process. The third is, using SSD data recovery software such as. This application is available for Windows and Mac.