Non-Volatile Memory (NVM) or Non-Volatile Storage is a type of computer memory that can retain stored information even after power is removed.
Examples of non-volatile memory include flash memory, read-only memory (ROM), ferroelectric RAM, most types of magnetic computer storage devices (e.g. hard disk drives, floppy disks, and magnetic tape), optical discs, and early computer storage methods such as paper tape and punched cards.
Non-volatile memory typically refers to storage in semiconductor memory chips, which store data in floating-gate memory cells consisting of floating-gate MOSFETs (metal–oxide–semiconductor field-effect transistors), including flash memory storage such as NAND flash and SSD, and ROM chips such as EPROM and EEPROM. It can also be classified as traditional non-volatile disk storage.