PCI Local Bus

Conventional PCI

PCI Local Bus
Three 5-volt 32-bit PCI expansion slots on a motherboard (PC bracket on left side)
Year created	June 22, 1992; 24 years ago (1992-06-22)
Created by	Intel
Supersedes	ISA, EISA, MCA, VLB
Superseded by	PCI Express (2004)
Width in bits	32 or 64
Speed	133 MB/s (32-bit at 33 MHz – the standard configuration) 266 MB/s (32-bit at 66 MHz or 64-bit at 33 MHz) 533 MB/s (64-bit at 66 MHz)
Style	Parallel
Hotplugging interface	Optional

Conventional PCI, often shortened to PCI, is a local computer bus for attaching hardware devices in a computer. PCI is the initialism for Peripheral Component Interconnect and is part of the PCI Local Bus standard. The PCI bus supports the functions found on a processor bus but in a standardized format that is independent of any particular processor's native bus. Devices connected to the PCI bus appear to a bus master to be connected directly to its own bus and are assigned addresses in the processor's address space. It is a parallel bus, synchronous to a single bus clock.

Attached devices can take either the form of an integrated circuit fitted onto the motherboard itself (called a planar device in the PCI specification) or an expansion card that fits into a slot. The PCI Local Bus was first implemented in IBM PC compatibles, where it displaced the combination of several slow ISA slots and one fast VESA Local Bus slot as the bus configuration. It has subsequently been adopted for other computer types. Typical PCI cards used in PCs include: network cards, sound cards, modems, extra ports such as USB or serial, TV tuner cards and disk controllers. PCI video cards replaced ISA and VESA cards until growing bandwidth requirements outgrew the capabilities of PCI. The preferred interface for video cards then became AGP, itself a superset of conventional PCI, before giving way to PCI Express.