Other examples of non-volatile memory include read-only memory (ROM), EPROM (erasable programmable ROM) and EEPROM (electrically erasable programmable ROM), ferroelectric RAM, most types of computer data storage devices (e.g. disk storage, hard disk drives, optical discs, floppy disks, and magnetic tape), and early computer storage methods such as punched tape and cards.
Mask ROMs are factory programmable only and typically used for large-volume products which are not required to be updated after the memory device is manufactured.
A one-time programmable (OTP) device may be implemented using an EPROM chip without the quartz window; this is less costly to manufacture.
NOR flash provides high-speed random access, reading and writing data in specific memory locations; it can retrieve as little as a single byte.
Less expensive than NOR flash at high densities, NAND technology offers higher capacity for the same-size silicon.
[4] Ferroelectric RAM (FeRAM, F-RAM or FRAM) is a form of random-access memory similar in construction to DRAM, both use a capacitor and transistor but instead of using a simple dielectric layer the capacitor, an F-RAM cell contains a thin ferroelectric film of lead zirconate titanate [Pb(Zr,Ti)O3], commonly referred to as PZT.
Due to the PZT crystal maintaining polarity, F-RAM retains its data memory when power is shut off or interrupted.
Due to this crystal structure and how it is influenced, F-RAM offers distinct properties from other nonvolatile memory options, including extremely high, although not infinite, endurance (exceeding 1016 read/write cycles for 3.3 V devices), ultra-low power consumption (since F-RAM does not require a charge pump like other non-volatile memories), single-cycle write speeds, and gamma radiation tolerance.
However, the discovery [10] that the popular high-κ gate dielectric HfO2 can be used as a low-voltage ReRAM has encouraged researchers to investigate more possibilities.
Optical discs store data by altering a pigment layer on a plastic disk and are similarly random access.
Read-only and read-write versions are available; removable media again allows indefinite expansion, and some automated systems (e.g. optical jukebox) were used to retrieve and mount disks under direct program control.
[13][14][15] Domain-wall memory (DWM) stores data in a magnetic tunnel junctions (MTJs), which works by controlling domain wall (DW) motion in ferromagnetic nanowires.