What is the difference between CMOS and BIOS

Difference: BIOS is a set of programs (software) solidified in read-only memory. This set of programs provides the most basic and direct hardware control for the computer. When the computer is turned on, the BIOS program automatically runs. The computer hardware will be detected and initialized to ensure that the system can work normally. If the hardware does not work properly, it will stop working immediately and feed back error device information to the user; BIOS can set hardware device parameters, but cannot store data. CMOS is a RAM chip, which is hardware. It is used to store hardware device parameters set by BIOS.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

What is BIOS

The so-called BIOS is actually the basic input-output system (Basic Input-Output System) of the microcomputer, and its content is integrated A ROM chip on the microcomputer motherboard mainly stores the most important basic input and output programs related to the microcomputer system, system information settings, power-on self-test program and system startup bootloader program, etc.

The function of BIOS, the BIOS ROM chip can not only be seen on the motherboard, but the BIOS management function determines whether the motherboard performance is superior to a large extent. BIOS management functions mainly include:

1. BIOS interrupt service program. The BIOS interrupt service program is essentially a programmable interface between software and hardware in a microcomputer system. It is mainly used to connect program software and microcomputer hardware. achieve connection between them. For example, the management of peripheral devices such as floppy disks, hard disks, optical drives, keyboards, and monitors in DOS and Windows operating systems is directly based on the BIOS system interrupt service program, and the operator can also access INT 5, INT 13 Wait for the interrupt point and directly call the BIOS interrupt service routine.

2. BIOS system setup program, the microcomputer component configuration record is placed in a readable and writable CMOS RAM chip, which mainly stores the basic system information, CPU characteristics, soft and hard drives, monitors, keyboards and other components Information. The "system setup program" is installed in the BIOS ROM chip, which is mainly used to set various parameters in the CMOS RAM. This program can enter the setting state by pressing a specific key when starting up, and provides a good interface for operators to use. In fact, this process of setting CMOS parameters is also customarily called "BIOS setting". Once the configuration information about the microcomputer in the CMOS RAM chip is incorrect, it will reduce the overall operating performance of the system and make the soft and hard drives and other components unrecognizable. In serious cases, it will cause a system software and hardware failure.

3. POST power-on self-test. After the microcomputer is powered on, the system first checks various internal devices through the POST (Power On Self Test, power-on self-test) program. Usually a complete POST self-test will include testing the CPU, 640K basic memory, extended memory above 1M, ROM, motherboard, CMOS memory, serial and parallel ports, display card, soft and hard disk subsystem and keyboard. Once the self-test is in progress If a problem is found, the system will give a prompt message or sound a warning siren.

4. The BIOS system starts the bootloader. After the system completes the POST self-test, the ROM BIOS first searches for the soft and hard disk drives, CD-ROMs, network servers, etc. according to the startup sequence saved in the system CMOS settings. Start the drive, read the operating system boot record, then transfer system control to the boot record, and let the boot record complete the smooth startup of the system.

What is CMOS

CMOS (originally refers to complementary metal oxide semiconductor memory, is a large-scale application in integrated circuit chips The raw material for manufacturing) is a readable and writable RAM chip on the microcomputer motherboard, which is mainly used to save the hardware configuration of the current system and the operator's settings for certain parameters. The CMOS RAM chip is powered by the system through a backup battery, so no matter it is in the shutdown state or encounters a system power outage, the CMOS information will not be lost.

Since the CMOS RAM chip itself is just a piece of memory and only has the function of saving data, the setting of various parameters in CMOS requires special procedures. Early CMOS setup programs resided on floppy disks (such as IBM's PC/AT models), which was very inconvenient to use. Most manufacturers now implement the CMOS setup program into the BIOS chip. You can enter the CMOS setup program by pressing a specific key when turning on the computer and set up the system very conveniently. Therefore, this CMOS setup is often called BIOS setup.

The difference between CMOS and BIOS

BIOS is a set of programs solidified in read-only memory. This set of programs provides computer The most basic and direct hardware control. When the computer is turned on, the BIOS program automatically runs. It will detect and initialize the computer hardware to ensure that the system can work normally. If the hardware does not work properly, it will immediately stop working and replace the faulty device. Information is fed back to the user. BIOS can set hardware device parameters, but cannot store data. CMOS is a RAM chip that is used to store hardware device parameters set by BIOS.

BIOS is software and program; CMOS is chip and hardware; through BIOS program, you can set the parameters in CMOS; CMOS is a chip, which stores important boot parameters on the motherboard, and uses CMOS button batteries to maintain power. ; Store parameters in CMOS, and write the set parameters into CMOS through the program to set it.

BIOS is the most basic and important program in the computer. Put this program in the memory (chip) BIOS that does not require power supply; it provides the lowest and most direct hardware control for the computer. The original operations of the computer are completed according to the content solidified in the BIOS; BIOS It is an interface or converter between hardware and software programs. It is responsible for solving the immediate needs of the hardware and executing the specific operating requirements of the software on the hardware. It plays a very important role in the computer system.

CMOS is a raw material used in large-scale integrated circuit chip manufacturing. It is a readable and writable RAM chip on the microcomputer motherboard. CMOS is mainly used to save the current system's hardware configuration and the operator's settings for certain parameters. The CMOS RAM chip is powered by the system through the backup battery. In the shutdown state, if the system still encounters a power outage, the CMOS information will not be lost.

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