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Peripheral Component Interconnect (PCI) Local Bus

Currently by far the most popular local I/O bus, the Peripheral Component Interconnect (PCI) bus was developed by Intel and introduced in 1993. It is geared specifically to fifth- and sixth-generation systems, although the latest generation 486 motherboards use PCI as well.

Like the VESA Local Bus, PCI is a 32-bit bus that normally runs at a maximum of 33 MHz. The key to PCI's advantages over its predecessor, the VESA local bus, lies in the chipset that controls it. The PCI bus is controlled by special circuitry in the chipset that is designed to handle it, where the VLB was basically just an extension of the 486 processor bus. PCI is not married to the 486 in this manner, and its chipset provides proper bus arbitration and control facilities, to enable PCI to do much more than VLB ever could. PCI is also used outside the PC platform, providing a degree of universality and allowing manufacturers to save on design costs.

The following sections provide more details on the functioning of the PCI bus in various areas.

Next: PCI Bus Performance

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