When Data Recovery is deleted from an SSD, the first action that advises is to switch off the system as quickly as possible – or even better, pull the plug – and do not switch it on again. An active SSD or memory card is like a ticking time bomb for deleted data and can result in fatal data loss with no chance of recovery.
From a purely technical point of view, TRIM is a command for the ATA interface according to the T13 standard. Depending on the system configuration, however, this command can differ and have a different name in different operating systems; however, is commonly known as the “TRIM” command. TRIM informs the controller of the solid state drive or flash memory card which Data Recovery has been deleted and is no longer physically needed.
TRIM supports the SSD in its regular garbage collection, which means that the SSD is informed of the deleted memory area . Not all – especially older – operating systems and SSDs support TRIM , so it is not a technical necessity . In the event of data loss and especially deleted data, TRIM can even be a fatal disadvantage.
TRIM tells the memory controller which memory areas still contain data that is no longer being used. Based on how solid state drives process information, the data on the drive is not erased at the direct command of the user. Instead of deleting the data , they are marked as memory areas that are no longer used. TRIM informs the data medium that this data can be removed .
In the case of write access to a sub-area of the affected Data Recovery block – in the case of an SSD this consists of a large number of pages which are processed simultaneously – the pages with the deleted Wikipedia data are no longer rewritten and remain empty. With other SSD models, such deleted pages are also deleted by the Active Garbage Collection while the device is idle .
The TRIM command did not exist in the pre-Windows 7 or pre-macOS 10.6.8 era: SSDs therefore had no information that certain sectors contained information that was no longer required. These only became known as soon as the computer instructed the SSD to write new information to this location.
This process required significantly more time for writing processes , since occupied areas always have to be emptied first before new information can be written into them. With the execution of TRIM and the subsequent active garbage collection, future write commands can be executed much more efficiently .
In addition to write efficiency, TRIM enables a longer Data Recovery service life for solid state drives . Each NAND cell has a finite shelf life , which correlates to the number of writes made. In order to be able to guarantee a long service life, all cells should be used to the same extent.
This wear compensation is made possible by the so-called “Wear Levelling” and is used with SSDs, memory cards and USB sticks. TRIM provides information to the flash media to organize erased but filled cells for writing to avoid unnecessary erase and rewrite operations.