What is the difference between BIOS and CMOS
In the daily operation and maintenance of computer process, often hear a number of statements about the BIOS settings and CMOS settings , many people often confuse the BIOS and CMOS. This article describes the CMOS settings and BIOS settings of distinction between the basic concepts and linkages.
What is BIOS?
The BIOS, is actually a computer's Basic Input-Output System, its content integrated in the computer a ROM chip on the motherboard, the main computer system holds the most important basic input and output procedures, system information set , turn the power on self test procedures and systems bootstrap procedures.
Function of the BIOS
BIOS ROM chip can not only see on the motherboard, and the BIOS management board to a large extent determines whether the performance is superior. BIOS management features include:
1. BIOS interrupt service routine
BIOS interrupt service routine is essentially a programmable interface between the hardware and software in the computer system, mainly used a interface between hardware and software . For example, DOS and Windows operating system on floppy disks, hard drives, optical drives, keyboards, monitors and other peripheral equipment management, are built directly into the system BIOS interrupt service routine basis, and the operator can also access the INT 5, INT 13 other breakpoints directly to call BIOS interrupt service routine.
2.BIOS system setup
Computer components configuration records are placed in the CMOSchip, mainly preserved in the basic situation of the system, CPU features, soft and hard drives, monitors, keyboards and other parts of the information. In the BIOS ROM chip with "System Setup", mainly used to set the parameters of the CMOS RAM. This program in boot time by pressing a particular key enter setup mode, and provides a good interface for the operator to use. In fact, this set the CMOS process parameters also called "BIOS settings." Once the CMOS RAM chip on the computer configuration information is incorrect, the light will make the system to reduce the overall operating performance, soft and hard drives and other components can not be identified, which will lead to a serious system hardware and software failures.
3. POST Power On Self Test
Computer power on, the system first by POST (Power On Self Test) procedure to check each device on the internal. Usually complete POST will include the CPU, 640K base memory, 1M or more extended memory, ROM, motherboard, CMOS memory, serial and parallel, video card, keyboard, harddisk subsystems for testing, once the self-test problems are detected, the system will give a message or a warning whistle.
4. BIOS boot bootloader
After system completed POST, ROM BIOS on the first follow the system CMOS settings stored in the boot sequence search for soft and hard drives and CD-ROM, network servers effectively boot drive, read into the operating system boot record, then gives the system control to the boot record,and lets boot record to complete the system by a smooth start.
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