Industry Standard Architecture
(architecture, standard)(ISA) A bus standard for IBM compatibles that extends the XT bus architecture to 16
bits. It also allows for bus mastering although only the
first 16 MB of main memory is available for direct access.
In reference to the XT bus architecture it is sometimes
referred to as "AT bus architecture".
Compare EISA, MCA.
Compare EISA, MCA.
This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)
ISA bus
(Industry Standard Architecture bus) An earlier hardware interface for connecting peripheral devices in PCs. Pronounced "eye-suh," ISA accepted cards for sound, display, hard drives and other devices. Originally called the "AT bus" and introduced with the IBM PC AT in 1984, the AT/ISA bus extended the PC bus from 8 to 16 bits. For several years, motherboards provided a mix of both 8-bit and 16-bit ISA slots. As PCI became popular, motherboards included only 16-bit ISA and PCI, and by the early 2000s, ISA was being replaced entirely by the PCI interface. See PC data buses and PCI. |
| ISA Slots |
|---|
| This diagram shows a motherboard with three 16-bit ISA slots. |
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| Mixed ISA Slots |
|---|
| Motherboards came with a mix of 8-bit (left) and 16-bit (right) slots such as this one. |
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| Earlier Expansion Cards |
|---|
| Except for the PCI bus, ISA, AGP, EISA, Micro Channel and VL-bus have all disappeared. |
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