Buses

bus is a subsystem that transfers data between components inside

a computer, or between computers.

Introduction of bus in (CSA)

Two type of buses

a bus located strictly within a CPU chip for communications among the components in a

CPU chip

Internal bus

External buses are supported by third-party hardware and software, and are more likely to

adhere to one of a number of industry standards for buses

bus is located outside a CPU chip for connecting the system components to the CPU.

External Bus

• This is the highest-level bus that the chipset uses to send information to and from the processor

Processor Bus (System

Bus)

• Higher-level architectures, employ a dedicated bus for accessing the system cache

Cache Bus (Backside

Bus)

• Second-level system bus that connects the memory subsystem to the chipset and the processor

Memory Bus

Bus Hierarchy

• For example, video cards, etc• The two most common local

I/O buses are the VLB and PCI.

The Local I/O Bus (High-speed

I/O Bus)

The illustration shows how the various buses connect to the

CPU.

1-Data and Address Buses

2-Bus Bandwidth

3-Bus Width

4-Bus Width

4 Characteristics of Bus

wide array of integrated

technologies on it, as it has multiple buses (ISA, PCI and AGP

to name a few) onboard

The ISA slots are the black slots on the lower portion of

the board in the image

Standards Bus Architecture

A-Industry Standard

Architecture (ISA) Bus

B-Micro Channel

Architecture (MCA) Bus

C-Extended Industry Standard

Architecture (EISA) Bus

D-VESA Local Bus

(VLB)

E-Peripheral Component Interconnect (PCI) Local

Bus

Bus standard

F-Accelerated Graphics Port (AGP)