Industry Standard Architecture

Industry Standard Architecture (ISA) is a computer expansion-bus architecture introduced with the IBM PC/AT in 1984. It connects expansion cards to a computer’s processor and memory system.

ISA bus: The parallel bus that carries data, addresses, and control signals between ISA cards and a computer. It is the shared electrical pathway at the heart of ISA.
IBM Personal Computer: IBM’s 1981 personal computer, built around an Intel 8088 processor and an open expansion bus. Its 8-bit expansion bus provided ISA’s original design foundation.
Expansion card: A circuit board installed in a computer to add functions or interfaces. ISA is the interface that lets these boards connect to the system.
Sound Blaster: A family of sound cards introduced by Creative Technology for IBM-compatible personal computers. ISA Sound Blaster cards made game and multimedia audio widely available.
IBM Micro Channel architecture: IBM’s proprietary expansion-bus architecture, introduced with the PS/2 line in 1987. IBM designed it to replace ISA with a faster, more controlled interface.
Memory-mapped I/O: A hardware design method that accesses device registers through addresses in the processor’s memory space. ISA cards can expose device registers through memory addresses.
IBM Personal Computer AT: IBM’s 1984 personal computer, based on the Intel 80286 and featuring a 16-bit expansion bus. Its expanded bus became the basis of the architecture’s familiar form.
Printed circuit board: A board that mechanically supports and electrically connects electronic components through conductive paths. An ISA card’s traces carry the bus signals to its components.
VGA: A display standard introduced by IBM in 1987 for computer graphics and monitors. ISA cards commonly provided VGA graphics in early PC-compatible systems.
Extended Industry Standard Architecture: A 32-bit PC expansion-bus standard developed by a consortium of computer manufacturers. EISA extended ISA compatibility while offering wider transfers and bus mastering.

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