UPGRADING REPAIRING PCs

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Chapter 2—System Components and Configuration
ISA
ISA
Figure 2.18 Pinouts for the 16-bit ISA bus.
Figure 2.19 The 8-bit and 16-bit ISA bus connectors.
VL-Bus Extension
Figure 2.20 The card connector for the EISA bus. The inner connectors
were used for the EISA cards, whereas the outer connectors supported 8-bit
and 16-bit ISA cards.
Figure 2.21 An example of a VL-Bus slot in an ISA system.
PCI
Intel developed PCI (Peripheral Component Interconnect) in 1992
to eventually replace ISA and its variations. Most PCI slots provide
32-bit transfers, with a 64-bit version of PCI being used in many
late-model file servers.
While a number of new “legacy-free” systems offer only PCI slots,
most systems you will encounter will also have one or more ISA
slots, as in Figure 2.21.
AGP
The latest expansion slot design is AGP (Accelerated Graphics Port),
introduced in 1996 to provide faster video performance in a dedicated
slot. AGP doesn’t replace PCI for general purposes, but AGP
video cards offer much faster performance than similar PCI cards,
and can also “borrow” from main memory for 3D texturing. Most
typical Pentium II/III, Celeron, Athlon, Duron, or Super Socket 7
systems include a single AGP slot as well as a mixture of PCI and
ISA slots (see Figure 2.22).
Note