Analysis of the function and function of Win7 system BIOS setup and CMOS setting

　　What is the BIOS?

The so-called BIOS, in fact, is the basic computer input and output system (basic Input-output System), its content integrated in the microcomputer motherboard on a ROM chip, mainly on the computer system of the most important basic input and output programs, System Information settings, Power-on on the Self-Test program and the system to start the bootstrap process.

　　The function of the BIOS

The BIOS ROM chip can be seen not only on the motherboard, but also how the BIOS management function determines the performance of the motherboard to a large extent.

1. BIOS Interrupt Service Program

The BIOS interrupt Service program is essentially a programmable interface between software and hardware in a microcomputer system, which is mainly used to realize the connection between program software and computer hardware. For example, the management of peripherals such as floppy disks, hard drives, optical drives, keyboards, monitors, and so on in DOS and Windows operating systems is directly based on the BIOS system Interrupt service program, and the operator can invoke the BIOS interrupt service directly by accessing breakpoints such as int 5, int 13, and so on.

2. BIOS System Setup program

The microcomputer part configuration record is placed in a readable and writable CMOS RAM chip, which mainly holds the information of the system basic condition, CPU characteristic, soft hard disk drive, monitor, keyboard and other parts. The System Setup program is installed in the BIOS ROM chip, which is used to set the parameters in the CMOS RAM. This program can enter the setting state by pressing a specific key while powering on, and provides a good interface for the operator to use. In fact, the process of setting the CMOS parameters is customarily referred to as "BIOS setup." Once the CMOS RAM chip in the configuration information about the computer is incorrect, the light will make the overall performance of the system reduced, soft hard drive and other parts can not be recognized, serious will cause a system of hardware and software failures.

3, post on the power self-test

After the microcomputer presses the power supply, the system first checks the internal equipment by the post (powered on self test, the Power self-test) program. Usually the full post self-test will include the CPU, 640K basic memory, 1M above the extended memory, ROM, motherboard, CMOS memory, serial port, display card, soft and hard plate system and keyboard test, once in the self-test found problems, the system will give a message or whistle warning.

4, the BIOS system to start the bootstrap process

After the system completes the post self-test, the ROM BIOS first searches for the soft hard drive and the CD-ROM, the network server and so on to start the drive effectively, reads into the operating system boot record, and then gives the system control to the boot record. And by the boot record to complete the system's smooth start.

　What is CMOS?

CMOS (intended to refer to complementary metal oxide semiconductor storage, is a large-scale use of integrated circuit chip manufacturing materials) is a microcomputer motherboard on a read-write RAM chip, mainly used to save the current system hardware configuration and operator of some parameters set. The Cmosram chip is powered by a backup battery, so the CMOS information will not be lost either in the shutdown State or when the system loses power.

Because the Cmosram chip itself is only a piece of memory, only has the function of saving data, so the parameters in the CMOS set to pass a special program. Early CMOS setup programs that reside on floppy disks (such as IBM's PC/AT model) are inconvenient to use. Most manufacturers now do the CMOS Setup program in the BIOS chip, in the power-on by pressing a specific key can enter the CMOS Setup program and very easy to set up the system, so this CMOS settings are often called BIOS settings.

　　Differences and connections between BIOS settings and CMOS settings

BIOS is an EPROM or EEPROM chip on the motherboard, which contains important information of the system and Setup program of setting system parameters (Biossetup program); CMOS is a read-write RAM chip on the motherboard that contains specific parameters for the configuration of the system, which can be read and written by the Setup program. The Cmosram chip is powered by a back-up battery, and the information is not lost even after the system loses power. BIOS and CMOS are both relevant and different: The System Setup program in the BIOS is the means to complete the CMOS parameter setting; Cmosram is not only the storage place of the BIOS setting system parameters, but also the result of the BIOS setting system parameters. Therefore, the complete argument should be "set the CMOS parameters through the BIOS setup program." Since the BIOS and CMOS are related to the system setup, so in the actual use of the process caused the BIOS settings and CMOS settings, in fact, refers to the same thing, but the BIOS and CMOS is two a completely different concept, must not be confused.

　When do you want to set up the BIOS or CMOS?

It is well known that the BIOS or CMOS setup is a very important system initialization work which is accomplished by the operator according to the actual situation of microcomputer. The BIOS or CMOS must be set up in the following situations:

1, New computer purchase

Even if the system with PNP function can only recognize a part of the computer peripherals, and the soft hard drive parameters, the current date, clock and other basic information must be set by the operator, so the newly purchased computer must be set to the CMOS parameters to tell the system the basic configuration of the whole computer.

2. New equipment

Since the system does not necessarily recognize the new device, it must be told by the CMOS settings. In addition, once the new device and the original device has an IRQ, DMA conflict, but also often need to pass through the BIOS settings to exclude.

Accidental loss of 3.CMOS data

In the case of system backup battery failure, the virus destroys the CMOS data program, and accidentally clears the CMOS parameter, the CMOS data is often accidentally lost. You can only re-enter the BIOS setup program to complete the new CMOS parameter settings.

4. System optimization

For memory read and write wait time, hard disk data transfer mode, internal/external cache use, energy conservation, power management, boot sequence, and other parameters, the BIOS in the scheduled settings for the system is not necessarily optimal, at this time often need to go through many tests to find the best combination of system optimization.