What is BIOS? What is the BIOS?

The BIOS (basic Input output system) basic output input systems. is a ROM chip integrated on the motherboard, which holds the system's most important computer essential input/output programs, System Information settings, power-on self-test and System startup self-test programs. The BIOS ROM chip is visible on the motherboard. Whether a motherboard is superior or not depends largely on the advanced BIOS management function on the board.

BIOS Main Features:

1, power-on self-test (Power On Self test): Check the central processing unit (CPU) and the status of the controller is normal.

2, initialization action: for memory, motherboard chipset, video card and peripheral devices to do initialization action.

3, Record system set Value: Provide the basic settings of each component, such as monitor, keyboard, processor, memory and so on.

4, provide resident Library: Provide operating system or application call interrupt resident program, such as int 10H.

5. Loading operating system: Loading operating system from storage device to random access memory.

Since the CMOS and BIOS are closely related to the computer system settings, the CMOS settings and BIOS settings, CMOS is the location of the system parameters, and the BIOS System Setup program is the means to complete the parameter settings. Therefore, it is accurate to say that the CMOS parameters are set through the BIOS setup program. And what we normally call CMOS settings and BIOS settings is its simplification, and to some extent it creates confusion between the two concepts.

The BIOS has the following meanings: BIOS interrupt routine; Post power self-test; system CMOS setup;

BIOS Interrupt routine: The BIOS Interrupt Service program. It is a programmable interface between software and hardware of computer system, which can be used to realize the function of program and computer hardware. Dos/windows operating system for soft, hard drive, CD-ROM and keyboard, display and other peripherals management is based on the system BIOS. Programmers can also invoke the BIOS interrupt routine directly by accessing interrupts such as int 5, int 13, and so on.

Second, the BIOS System Setup program: The computer parts configuration is placed in a erasable CMOS RAM chip, it holds the system CPU, soft hard drive, monitor, keyboard and other parts of the information. After shutdown, the system is powered by a backup battery to the CMOS to maintain the information. If the configuration information about the computer in CMOS is incorrect, the system performance will be reduced, the parts cannot be recognized, and the hardware and software faults of the systems can be caused. The BIOS ROM chip contains a program called the System Setup program, which is used to set parameters in CMOS RAM. This program usually presses a key or a set of keys to enter in the power-on, it provides the good interface for the user to use. This process of setting CMOS parameters is customarily referred to as "BIOS setup". BIOS setup is required for newly purchased computers or systems with new components.

Post Power self-test: When the computer is plugged in, the system will have a process for checking internal devices, which is done by a program that is commonly called post (Power On Self test, power-on self-test). This is also a function of the BIOS. The full post self-test will include CPU, 640K basic memory, extended memory above 1M, ROM, motherboard, CMOS memory, serial port, display card, soft hard disk system and keyboard test. If the problem is found in the self-test, the system will give a message or whistle warning.

Four, the BIOS system initiates the Self-Test procedure: After completes post self-test, the ROM BIOS will search for the soft hard disk drive and the CDROM, the network server and so on the valid driver program in the system CMOS setup, reads into the operating system boot record, then gives the system control authority to the boot record, The boot record completes the system startup.