BASIC INPUT OUTPUT SYSTEM

During the late s and s it became economical to move an increasing number of peripheral functions onto the motherboard see above. In the late s motherboards began to include single ICs called Super IO chips capable of supporting a set of lowspeed peripherals keyboard mouse floppy disk drive serial ports and parallel ports. As of the late s many personal computer motherboards support a full range of audio video storage and networking functions without the need for any expansion cards at all higherend systems for D gaming and computer graphics typically retain only the graphics card as a separate component.Popular personal computers such as the Apple II and IBM PC had published schematic diagrams and other documentation which permitted rapid reverseengineering and thirdparty replacement motherboards. The term mainboard is archaicly applied to devices with a single board and no additional expansions or capability. In modern terms this would include embedded systems and controlling boards in telvisions washing machines etc.


Motherboards contain some nonvolatile memory to initialize the system and load an operating system from some external peripheral device. Microcomputers such as the Apple II and IBM PC used readonly memory chips mounted in sockets on the motherboard. At power up the central processor would load its program counter with the address of the boot ROM and start executing ROM instructions displaying system information on the screen and running memory checks which would in turn start loading memory from an external or peripheral device disk drive if one isnt available then the computer can perform tasks from other memory stores or displays an error message depending on the model and design of the computer and version of the bios.

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