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)
8-bit XT: Adlib FM Sound card
Fast SCSI RAID controller (DPT PM2022)
16-bit ISA: Madge 4/16 Mbps Token Ring NIC
ELSA Winner 1000 Video card for ISA and EISA
16-bit ISA: Ethernet 10Base-5/2 NIC
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8-bit XT: US Robotics 56k Modem

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

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In IBM products, it superseded the ISA bus and was itself subsequently superseded by the PCI bus architecture.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

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.

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.

Three 5-volt 32-bit PCI expansion slots on a motherboard (PC bracket on left side)

Peripheral Component Interconnect

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Local computer bus for attaching hardware devices in a computer and is part of the PCI Local Bus standard.

Local computer bus for attaching hardware devices in a computer and is part of the PCI Local Bus standard.

Three 5-volt 32-bit PCI expansion slots on a motherboard (PC bracket on left side)
A typical 32-bit, 5 V-only PCI card, in this case, a SCSI adapter from Adaptec
A motherboard with two 32-bit PCI slots and two sizes of PCI Express slots
Diagram showing the different key positions for 32-bit and 64-bit PCI cards
A PCI-X Gigabit Ethernet expansion card with both 5 V and 3.3 V support notches, side B toward the camera
A semi-inserted PCI-X card in a 32-bit PCI slot, illustrating the need for the rightmost notch and the extra room on the motherboard to remain backward compatible
64-bit SCSI card working in a 32-bit PCI slot
A Mini PCI slot
Mini PCI Wi-Fi card Type IIIB
PCI-to-MiniPCI converter Type III
MiniPCI and MiniPCI Express cards in comparison
A PCI POST card that displays power-on self-test (POST) numbers during BIOS startup
A full-height bracket
A low profile one

The PCI Local Bus was first implemented in IBM PC compatibles, where it displaced the combination of several slow Industry Standard Architecture (ISA) slots and one fast VESA Local Bus (VLB) slot as the bus configuration.

PCI was immediately put to use in servers, replacing Micro Channel architecture (MCA) and Extended Industry Standard Architecture (EISA) as the server expansion bus of choice.

Multi-I/O-Controller with 1×IDE/SCSI-2/FDD/parallel/2×RS232/Game

VESA Local Bus

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Short-lived expansion bus introduced during the i486 generation of x86 IBM-compatible personal computers.

Short-lived expansion bus introduced during the i486 generation of x86 IBM-compatible personal computers.

Multi-I/O-Controller with 1×IDE/SCSI-2/FDD/parallel/2×RS232/Game
An ATI MACH64 SVGA VLB graphics card
Computer motherboard with 7 ISA slots of various feature levels. The top three are 16-bit ISA. The middle three are VLB; 16-bit ISA with the added slot (leftmost brown sections). The bottom (shorter) slot is 8-bit ISA. A card installed in this motherboard would have its mounting bracket on the right, which normally would be the "back" of the computer case.
"VIP" motherboard GA486IM from Gigabyte Technology
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Created by VESA (Video Electronics Standards Association), the VESA Local Bus worked alongside the then-dominant ISA bus to provide a standardized high-speed conduit intended primarily to accelerate video (graphics) operations.

While an extension of the royalty-free ISA bus in the form of EISA open standard was developed to counter MCA, its bandwidth of 33.32 MB/s was unable to offer enough improvement over ISA to meet the significant increase in bandwidth desired for graphics.

Compaq

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American information technology company founded in 1982 that developed, sold, and supported computers and related products and services.

American information technology company founded in 1982 that developed, sold, and supported computers and related products and services.

First Compaq logo, used until 1993
Compaq Portable
Compaq Portable 386 BIOS
Aerial map of the Compaq headquarters, now the HP USA campus in unincorporated Harris County, Texas
Former Compaq headquarters, now the Hewlett-Packard United States campus
Post merger logo for Compaq products.
An example of a HP Compaq.

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.

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.