It was announced in September 1988 by a consortium of PC clone vendors (the Gang of Nine) as an alternative to IBM's proprietary Micro Channel architecture (MCA) in its PS/2 series.

[3] EISA was much favoured by manufacturers due to the proprietary nature of MCA, and even IBM produced some machines supporting it.

EISA was also available on some non-IBM-compatible machines such as the DEC AlphaServer, HP 9000 D-class, SGI Indigo2 and MIPS Magnum.

The original IBM PC included five 8-bit slots, running at the system clock speed of 4.77 MHz.

As the PC-clone industry continued to build momentum in the mid- to late-1980s, several problems with the bus began to be apparent.

However, in an effort to reassert its dominant role, IBM patented the bus and placed stringent licensing and royalty policies on its use.

A few manufacturers did produce licensed MCA machines (most notably, NCR), but overall the industry balked at IBM's restrictions.

[9][10] Intel introduced a lower-cost variant as the 82350DT, announced in April 1991; it began shipping in June of that year.

[citation needed] The SystemPro, being one of the first PC-style systems designed as a network server, was built from the ground up to take full advantage of the EISA bus.

Thus, even systems that didn't use the EISA bus gained the advantage of having the ISA standardized, which contributed to its longevity.

The Gang of Nine was the informal name given to the consortium of personal computer manufacturing companies, led by Compaq, that together created the EISA bus.

The utility software would detect all EISA cards in the system and could configure any hardware resources (interrupts, memory ports, etc.)

[6] It debuted the AT bus-based PS/2 Model 30 286 in Manhattan at the same time as the EISA announcement elsewhere in the city, 17 months after tellilng customers that the AT bus was obsolete.

Some customers wished that a 32-bit bus had been available years earlier, and thought that IBM's rivals should now adopt MCA, for which almost 400 expansion cards were available by EISA's introduction.