A computer program, firmware, or microprocessor of a computer that is used to start the computer when powered on. Commonly abbreviated as BIOS. Stored in the non-volatile random access memory (NVRAM) of a computer, usually a complementary metal semiconductor (CMOS). The BIOS includes low-level code that:
- initiates and enable communications with hardware devices;
- performs the power-on self test (POST) to test the computers components (including the CPU, memory, storage, and input devices); and
- loads an operating system that interfaces with the user.