Local bus
Encyclopedia
In computer science
, a local bus is a computer bus
that connects directly, or almost directly, from the CPU
to one or more slots on the expansion bus
. The significance of direct connection to the CPU is avoiding the bottleneck created by the expansion bus, thus providing fast throughput
. There are several local buses built into various types of computers to increase the speed of data transfer. Local buses for expanded memory and video boards are the most common.
VESA Local Bus
is an example of a local bus design.
Although VL-Bus was later succeeded by AGP
, it is not correct to categorize AGP as a local bus. Whereas VL-Bus operated on the CPU's memory bus at the CPU's clock speed, an AGP peripheral runs at specified clock speeds that run independently of the CPU clock (usually using a divider of the CPU clock).
Computer science
Computer science or computing science is the study of the theoretical foundations of information and computation and of practical techniques for their implementation and application in computer systems...
, a local bus is a computer bus
Computer bus
In computer architecture, a bus is a subsystem that transfers data between components inside a computer, or between computers.Early computer buses were literally parallel electrical wires with multiple connections, but the term is now used for any physical arrangement that provides the same...
that connects directly, or almost directly, from the CPU
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
to one or more slots on the expansion bus
Expansion bus
An expansion bus is made up of electronic pathways which move information between the internal hardware of a computer system and peripheral devices. It is a collection of wires and protocols that allows for the expansion of a computer.- History :The first kit-built microcomputers used a bus design...
. The significance of direct connection to the CPU is avoiding the bottleneck created by the expansion bus, thus providing fast throughput
Throughput
In communication networks, such as Ethernet or packet radio, throughput or network throughput is the average rate of successful message delivery over a communication channel. This data may be delivered over a physical or logical link, or pass through a certain network node...
. There are several local buses built into various types of computers to increase the speed of data transfer. Local buses for expanded memory and video boards are the most common.
VESA Local Bus
VESA Local Bus
The VESA Local Bus was mostly used in personal computers. VESA Local Bus worked alongside the ISA bus; it acted as a high-speed conduit for memory-mapped I/O and DMA, while the ISA bus handled interrupts and port-mapped I/O.-Historical overview:In the early 1990s, the I/O bandwidth of...
is an example of a local bus design.
Although VL-Bus was later succeeded by AGP
Accelerated Graphics Port
The Accelerated Graphics Port is a high-speed point-to-point channel for attaching a video card to a computer's motherboard, primarily to assist in the acceleration of 3D computer graphics. Since 2004 AGP has been progressively phased out in favor of PCI Express...
, it is not correct to categorize AGP as a local bus. Whereas VL-Bus operated on the CPU's memory bus at the CPU's clock speed, an AGP peripheral runs at specified clock speeds that run independently of the CPU clock (usually using a divider of the CPU clock).