Technology & Computing
The ISA bus and the open PC architecture
The problem
A personal computer that could not be extended was a dead end; every new capability meant a new machine.
The innovation
A standard internal expansion bus letting third parties build cards — graphics, sound, networking, storage — that any PC could accept.
How it worked
A published slot and signalling standard turns the computer into a platform rather than a product.
Why it mattered
Created the entire PC peripheral industry.
The legacy
PCI, AGP, PCIe and the modern component ecosystem descend from this decision. Dean holds three of the original nine IBM PC patents.
You use this today
Any desktop where you can add a graphics card.
Sources
IBM PC original patent records
Mark Dean inductee record
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