Trim command (SSD)

Solid-state drives(SSD) use NAND flashes for data storage and transfer.

NAND flashes consist of small data pages that have been combined into data blocks. When a data page is erased, it is not deleted, rather it is only marked for deletion. This is due to the fact that, from the point of view of the hierarchy, only data blocks and not individual data pages can be deleted. Only later, when the memory area to be deleted is needed, the marked data pages are combined into a data block and removed together. This process slows down the storing of new data on solid-state drives.

The TRIM command speeds up storage because it allows the operating system to more quickly find marked data pages that are to be erased. If these marked data pages are deleted in advance, then this saves time for storing new data. The TRIM command must be supported by the SSD drive and the operating system. This includes that the SSD drive receives information about the deletion from the operating system and that the storage space can be written to again.