 The cost per gigabyte of flash memory remains significantly higher than that of hard disks.Also flash memory has a finite number of P/E cycles, but this seems to be currently under control since warranties on flash-based SSDs are approaching those of current hard drives.In addition, deleted files on SSDs can remain for an indefinite period of time before being overwritten by fresh data; erasure or shred techniques or software that work well on magnetic hard disk drives have no effect on SSDs, compromising security and forensic examination.