Which technology does BIOS use to store its firmware?

The technology that BIOS uses to store its firmware is Read-Only Memory (ROM). BIOS, which stands for Basic Input/Output System, is essential for booting up a computer and performing hardware initialization. ROM is a non-volatile memory type that retains data even when the power is turned off, making it suitable for storing BIOS firmware that must be accessible whenever the system starts.

Using ROM allows for the BIOS to be pre-programmed with instructions necessary for hardware initialization and to load the operating system into memory. This firmware is not intended to be modified frequently, which aligns with the characteristics of ROM. Although some modern systems may use flash memory, which is a type of non-volatile storage that can be written to and erased, the traditional understanding in the context of BIOS is that it is stored in ROM.

This specifically contrasts with technologies like RAM, which is volatile and loses its data when the power is cut, and magnetic storage, which is generally used for larger data storage needs and is slower than ROM in terms of access time.