One 8-bit and five 16-bit ISA slots on a motherboard
Three EISA slots
8-bit XT, 16-bit ISA, EISA (top to bottom)
SCSI controller (Adaptec AHA-1740)
First Compaq logo, used until 1993
8-bit XT: Adlib FM Sound card
Fast SCSI RAID controller (DPT PM2022)
Compaq Portable
16-bit ISA: Madge 4/16 Mbps Token Ring NIC
ELSA Winner 1000 Video card for ISA and EISA
Compaq Portable 386 BIOS
16-bit ISA: Ethernet 10Base-5/2 NIC
200px
Aerial map of the Compaq headquarters, now the HP USA campus in unincorporated Harris County, Texas
8-bit XT: US Robotics 56k Modem
Former Compaq headquarters, now the Hewlett-Packard United States campus
Post merger logo for Compaq products.
An example of a HP Compaq.

In comparison with the AT bus, which the Gang of Nine retroactively renamed to the ISA bus to avoid infringing IBM's trademark on its PC/AT computer, EISA is extended to 32 bits and allows more than one CPU to share the bus.

- Extended Industry Standard Architecture

An attempt to extend it to 32 bits, called Extended Industry Standard Architecture (EISA), was not very successful, however.

- Industry Standard Architecture

Compaq created the term "Industry Standard Architecture" (ISA) to replace "PC compatible".

- Industry Standard Architecture

Compaq Computer Corporation

- Extended Industry Standard Architecture

Compaq's technical leadership and the rivalry with IBM was emphasized when the SystemPro server was launched in late 1989 – this was a true server product with standard support for a second CPU and RAID, but also the first product to feature the EISA bus, designed in reaction to IBM's MCA (MicroChannel Architecture) which was incompatible with the original AT bus.

- Compaq

Although Compaq had become successful by being 100 percent IBM-compatible, it decided to continue with the original AT bus—which it renamed ISA—instead of licensing IBM's MCA.

- Compaq
One 8-bit and five 16-bit ISA slots on a motherboard

2 related topics with Alpha

Overall

The Compaq Portable was one of the first nearly 100% IBM-compatible PCs.

IBM PC compatible

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IBM PC compatible computers are similar to the original IBM PC, XT, and AT that are able to use the same software and expansion cards.

IBM PC compatible computers are similar to the original IBM PC, XT, and AT that are able to use the same software and expansion cards.

The Compaq Portable was one of the first nearly 100% IBM-compatible PCs.
The original IBM PC (Model 5150) motivated the production of clones during the early 1980s.
The DEC Rainbow 100 runs MS-DOS but is not compatible with the IBM PC.
MS-DOS version 1.12 for Compaq Personal Computers
The PowerPak 286, an IBM PC compatible computer running AutoCAD under MS-DOS.

Soon after in 1982, Compaq released the very successful Compaq Portable in 1982, also with a clean-room reverse-engineered BIOS, and also not challenged legally by IBM.

It was later re-named the Industry Standard Architecture (ISA) bus, after the Extended Industry Standard Architecture bus open standard for IBM PC compatibles was announced in September 1988 by a consortium of PC clone vendors, led by Compaq and called the Gang of Nine, as an alternative to IBM's proprietary Micro Channel architecture (MCA) introduced in its PS/2 series.

IBM XGA-2 32-bit Graphics Card

Micro Channel architecture

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Proprietary 16- or 32-bit parallel computer bus introduced by IBM in 1987 which was used on PS/2 and other computers until the mid-1990s.

Proprietary 16- or 32-bit parallel computer bus introduced by IBM in 1987 which was used on PS/2 and other computers until the mid-1990s.

IBM XGA-2 32-bit Graphics Card
IBM XGA-2 32-bit Graphics Card
CHIPS P82C612 in a PLCC package
IBM 83X9648 16-bit Network Interface Card
Roland MPU-IMC; second revision with IRQ jumpers
ChipChat 16 with software-controlled IRQ selection

In IBM products, it superseded the ISA bus and was itself subsequently superseded by the PCI bus architecture.

For servers the technical limitations of the old ISA were too great, and, in late 1988, the "Gang of Nine", led by Compaq, announced a rival high-performance bus - Extended Industry Standard Architecture (EISA).