What type of memory is non-volatile and used to store firmware?

The correct answer is ROM, which stands for Read-Only Memory. ROM is a type of non-volatile memory, meaning that the data stored in it is retained even when the power is turned off. This characteristic makes it ideal for storing firmware—the essential software that controls hardware devices, providing the necessary instructions for how the device operates. Firmware is typically written once (or infrequently updated) and does not require constant changes, which aligns perfectly with the properties of ROM.

Unlike RAM (Random Access Memory), which is volatile and loses all data when the power is off, ROM is specifically designed for permanent storage of the firmware code. Cache memory, while important for speeding up processes, is also volatile and does not store firmware. Flash memory, while it is non-volatile and can store firmware, is primarily used in devices like USB drives and SSDs for data storage rather than the firmware of the system itself. Thus, ROM stands out as the ideal type of memory used specifically for storing firmware.