Final answer:
The three parts of a computer's BIOS are the Post Test, Boot Loader, and BIOS drivers, collectively responsible for hardware initialization, operating system loading, and providing basic control over hardware components.
Step-by-step explanation:
The three main components of a computer's basic input/output services (BIOS) are the Post Test, Boot Loader, and the BIOS driver. The Post Test checks hardware and makes sure everything is working properly when the computer starts up. The Boot Loader loads the computer's operating system (OS) into memory. The BIOS drivers are low-level drivers that give the computer basic operational control over your computer's hardware.
BIOS plays a critical role in a computer's functionality by initiating hardware during the booting process and providing runtime services for operating systems and programs. BIOS firmware has evolved over the years, but its fundamental role in computer operation remains unchanged. The BIOS ensures that all the system's devices are in a functional state before the OS takes over. The fact that computers can perform complex computations, guide modern transportation, or store vast amounts of information is heavily reliant on the successful operation of the BIOS. As such, the BIOS is a cornerstone of modern computing.