Alternatively known as one address bus, data bus, or local bus, a bus is a connection in between components or devices connected to a computer. For example, a bus carries data in between a CPU and the system memory via the motherboard.

You are watching: A bus can be internal or external.

Why is a computer bus referred to as a bus?

You can think the a computer system bus choose public transport or a institution bus. These varieties of buses are capable of transporting world from one destination to another destination. Like these buses, a computer bus transmits data from one ar or maker to another location or device.

A computer system bus maintains a strictly schedule, "picking up" data and also "dropping that off" in ~ a consistent interval. Because that example, if a bus operates at a frequency of 200 MHz, the completes 200 million data transfers every second. This speed is referred to as the bus width.


Bus is no an abbreviation or acronym.

Computer bus overview

The bus contains multiple wires (signal lines) through addressing information describing the memory ar of wherein the data is sent or retrieved. Each cable in the bus dead a bit(s) the information, which way the much more wires a bus has, the an ext information it deserve to address. For example, a computer with a 32-bit address bus can deal with 4 GB that memory, and a computer system with a 36-bit bus can resolve 64 GB that memory.

The illustration below shows the different types of computer system buses and how they attach devices top top the motherboard.


Types of computer system buses

A bus is one of two people a parallel or serial bus, and either one internal bus (local bus) or one external bus (expansion bus).

Internal bus vs. External bus

An inner bus enables the communication in between internal components, such as a video clip card and also memory. An outside bus is capable of connecting with outside peripherals, such together a USB or SCSI device.

Parallel bus vs. Serial bus

A computer system bus can transmit the data using either a parallel or serial method of communication. With a parallel bus, data istransfer number of bits in ~ a time. However, v a serial bus, the data is transferred one little bit at a time.

Address bus vs. Data bus

With computer system memory, a computer system address bus is the bus containing the memory location (memory address) of whereby data is situated in the computer system memory. When the computer understands whereby to gain the information, the data bus is supplied to transport that data.

Bus speeds

A computer system or device"s bus speed is measure in MHz, e.g., one FSB might operate in ~ a frequency that 100 MHz. The throughput of a bus is measure up in bits per 2nd or megabytes every second.

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Examples of computer buses


AGP ATA Back-side bus BSB EISA eSATA ExpressCard FireWire Front next bus FSB

HyperTransport principle ISA MCA NuBus


SATA SBus SCSI device bus Thunderbolt USB VLB VMEbus

Most popular computer system buses

Today, numerous of the buses detailed above room no longer used or are not together common. Listed below is a listing of the most typical buses and how they are used with a computer.

ADB, AGP, AMR, in ~ Bus, Back-side bus, Channel, Clock speed, CNR, EISA, Hardware terms, HyperTransport, IDE, Input/output bus, ISA, MCA, Motherboard terms, Multiplier, NuBus, PCI, PCI Express, PCMCIA, SBus, SCSI, SMBus, USB, Vitesse-Bus, VLB, XT