The encyclopedia · Software & IT · Technical decision · 1992-1995
Intel opened the PCI bus to an industry group, and it swept the PC bus wars
Intel designed PCI and handed the spec to an industry group, so every vendor could build cards and PCI replaced the VESA bus.
Intel · PCI-SIG
the move
PC peripherals needed a faster bus than ISA, but the VESA Local Bus attached directly to the 80486's local bus, which Intel feared would let an outsider control the architecture its processors depended on.
Intel designed its own high-performance bus and announced PCI in 1992. To speed adoption it deliberately turned the specification over to the PCI Special Interest Group, an industry body, rather than keep it proprietary.
The move to an open spec let every card and chip vendor build to the same interface, so PCI became the accepted PC bus and swept away the competing VESA, ISA and EISA buses.
The first spec was a 32-bit 33 MHz bus capable of burst transfers, but early versions were interpreted differently until PCI 2.1 added parity and interoperability, at which point a stable PCI went mainstream.
why it works
- An open spec lets every vendor build without licensing or trust barriers.
- Handing control to a group removed the fear of Intel dominance.
- A processor-independent bus fit any CPU, not just Intel's.
- Once vendors standardize, network effects lock out rivals.
what transfers
If you own a de facto interface, opening the standard often wins more than guarding it: letting rivals build on your spec turns them into adopters instead of competitors.
what came after
PCI became the standard PC expansion bus through the 1990s and was later succeeded by PCI Express, still stewarded by PCI-SIG, so the open-spec model Intel chose in 1992 set the template for a generation of PC interconnects.
references
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