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Buses. Bus : electrical channel that allows various devices inside the computer to communicate with each other Bus width (the size of the bus) determines the number of bits that can be transmitted at one time
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Buses • Bus: electrical channel that allows various devices inside the computer to communicate with each other • Bus width (the size of the bus) determines the number of bits that can be transmitted at one time • Word size: the number of bits the processor can interpret and execute at a give time (usually the same as bus width)
Types of Expansion Buses • Expansion bus: a type of bus that allows the processor to communicate with peripheral devices • Expansion bus type determines the type of expansion card you can add • Types of expansion buses: • ISA (Industry Standard Architecture) • Local Bus • VESA local bus • PCI (Peripheral Component Interconnect) • AGP (Accelerated Graphics Port) • USB (Universal Serial Bus) • PC card bus
Bays • Bay: open area inside the system unit used to install additional equipment • Drive bays: • Used for disk drives • External (exposed) drive bay • Can be accessed from outside the system unit • Examples: DVD-ROM drive, CD-RW drive, floppy disk drive, • Internal (hidden) drive bay • Completely concealed within the system unit • Hard disks drives are installed in internal bays
Power Supply • Most personal computers plug into standard wall outlets, which supply an alternating current (AC) of 115 to 120 volts. • This type of current will not power a computer, which requires a direct current (DC) from 5 to 12 volts • Power Supply: the component of the system unit that converts the wall outlet AC power into DC power • AC adapter: an external power supply that converts power for external peripheral devices such as an external modem, speakers, or a tape drive • One end plugs into the wall outlet and the other end attaches to the peripheral