In computing, firmware is software that is embedded in a hardware device, that allows reading and executing the software, and can be edited (e.g., writing or deleting data by an end user).

Examples of firmware include:

• the BIOS found in personal computers,
• Open Firmware, used in Apple Macintosh computers,
• the computer program in a read-only memory (ROM) integrated circuit (A hardware configuration is usually used to represent the software.),
• the erasable programmable read-only memory (EPROM) chip, whose program may be modified by special external hardware, but not by an application program.

Source: from Federal Standard 1037C and from MIL-STD-188

Unauthorised modified firmware is sometimes used to provide functionality not intended by the manufacturer, for example to defeat the region encoding of DVD players.

See also

• Microprogram
• Flash memory