Enhanced ISA (EISA)
In 1988, an industry group answered the challenge of MCA and released a new open standard called Enhanced ISA (EISA-pronounced "ee-suh"). It's a 32-bit, 8-MHz standard.
Unlike MCA, EISA uses a variation of the ISA slot that accepts older ISA cards, with a two-step design that uses a shallow set of pins to attach to ISA cards and a deeper connection for attaching to EISA cards. In other words, ISA cards slip part-way down into the socket; EISA cards seat farther down.
CAUTION
Be very careful to line up cards being placed in an EISA slot precisely and push straight down! If you try to angle the card in, it can be very difficult to seat and you might damage either the connector or the slot.
Although EISA is faster and cheaper than MCA, it never gained much more acceptance than MCA.
Confusion between MCA and EISA technology-along with a limited need for cards that ran at the faster rate and the fact that only a few display, drive controller, and network cards were made available-led to the early demise of both bus technologies. Figures 10.3 and 10.4 show how the slot design of the two technologies differs.
Figure 10.3 Top view of ISA and EISA bus
Figure 10.4 Cross section of ISA and EISA bus