TRIM

SSD TRIM Marks Discarded Data for Flash Reuse

Deleting a file changes filesystem metadata, but that action does not automatically tell a solid-state drive which flash pages no longer contain useful data. From the drive’s point of view, previously written logical block addresses can remain valid until the host explicitly replaces them or marks them as discarded. TRIM closes that information gap. The operating system can notify the storage device that selected logical blocks no longer need their old contents. The SSD may then treat the associated data as disposable during its internal space-management work.