Bus

When referring to a computer, the bus also known as the address bus, data bus, or local bus is a data connection between two or more devices connected to the computer. For example, a bus enables a computer processor to communicate with the memory or a video card to communicate with the memory.

Computer Bus

The bus contains multiple wires (signal lines) that contain addressing information that describes the memory location of where the data is being sent or where it is being retrieved. Each wire in the bus carries a single bit of information, which means the more wires a bus has the more information it can address. For example, a computer with a 32-bit address bus can address 4GB of memory, and a computer with a 36-bit bus can address 64GB of memory.

A bus is capable of being a parallel or serial bus and today all computers utilize two bus types, an internal bus or local bus and an external bus, also called the expansion bus. An internal bus enables a communication between internal components such as a computer video card and memory and an external bus is capable of communicating with external components such as a USB or SCSI device.

A computer or device's bus speed is listed as a MHz, e.g. 100MHz FSB. The throughput of a bus is measured in bits per second or megabytes per second.

Examples of computer buses

A-F G-N O-P P-Z
AGP
ATA
EISA
eSATA
ExpressCard
Firewire
FSB
HyperTransport
IDE
ISA
MCA
NuBus
PATA
PC Card
PCI
PCIe
PCMCIA
SATA
SBus
SCSI
USB
VLB
VME Bus

Related pages

Also see: ADB, AGP, AMR, AT Bus, CNR, Back Side Bus, EISA, Front Side Bus, HyperTransport, IDE, Input/output bus, ISA, Internal data bus, MCA, NuBus, Motherboard terms, Multiplier, PCI, PCI Express, PCMCIA, SBus, SCSI, SMBus, USB, Vitesse-Bus, VLB, XT