The BIOS is Basic Input Output System and Complementary Metal-Oxide Semiconductor (CMOS) are present on the motherboard. Full form of BIOS is Basic Input Output System.
What is BIOS In PC?
- Basic Input Output System(BIOS) is the basic program is help an interface between the operating system and the motherboard.
- The BIOS is stored in the ROM and cannot be rewritten.
- When the computer power supply is on, it needs instructions to start.
- BIOS contain the instructions for the starting up of the computer.
- The BIOS runs when the compute is switched.
- BIOS perform POWER ON SELF TEST(POST) and boot start up operation which is program that runs automatically when the system is booted.\
It performs a Power On Self Test (POST) that checks that the hardware is functioning properly and the hardware device are present. It checks whether the operating system is present on the hard drive. BIOS invoke the bootstrap loader to load the operating system into memory.
Basic Input Output System(BIOS) can be configured using an interface named BIOS setup, which can be accessed when the computer is booting up (by pressing the DEL key).
CMOS Chip and BIOS Chip.
BIOS ROMS are accompanied by a smaller CMOS (CMOS is a type of memory technology) memory chip. When the computer is turned off, the power supply stops providing electricity to the motherboard. When the compute is turned on again, the system still displays the correct clock time. This is because the CMOS chip saves some system information, such as time, system date and essential system settings.
CMOS is kept powered by a button battery located on the motherboard. When the computer is shutdown, still the CMOS chip is in working mode. Information of the hardware installed in the computer (such as the number of tracks or sectors on each hard drive) is stored in the CMOS chip.
BIOS is setup instruction i.e. built in utility in BIOS. It display system setting and find the bootable device, Loads the interrupt handler and device driver, also initialize the register.
Basic input output system is a permanent part of computer. Which provides the system of setting and resources(printer, speaker) present on the computer system. BIOS is not stored in RAM and hard-disk i.e. in a ROM memory chip.