Even if data appears contiguous to the software, the physical flash memory (NAND) may store it in non-contiguous locations due to background tasks like garbage collection .
If fragmentation is high, the host instructs the device to perform physical defragmentation . FBO Delivers Sustained Mobile Phone Performance
As a mobile device is used, files are constantly written, deleted, and modified. Over time, this leads to two types of fragmentation: Even if data appears contiguous to the software,