3Com TokenLink 3C339, User Manual

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1-2 C
HAPTER
1: I
NTRODUCTION
PCI Technology
The PCI local bus provides a processor-independent
data path between the CPU in a PC and high-speed
peripherals. This high-performance bus accommodates
multiple high-performance peripheral devices for
networking and disk subsystems, graphics, full-motion
video, and multimedia.
There are two types of PCI devices: a master that
transfers information directly to system memory without
interrupting the system processor; and a target, which
accepts commands and responds to requests from a
master. The 3C339 PCI NIC is a master device.
A shared expansion backplate slot on the PCI device
provides access to one of two types of NICs: a PCI NIC
and an ISA NIC, for example, or a PCI NIC and an EISA
NIC. Only one NIC at a time can be installed in a shared
slot. Manufacturers are currently producing computers
that support the PCI bus in conjunction with conventional
ISA or EISA buses in the same chassis.
The PCI 32-bit bus supports multiple peripheral
components and add-in cards at a peak bandwidth of
132 Mbps, which is up to an order of magnitude greater
than that of ISA, EISA, and MCA PC buses. Automatic
configuration sets the basic configuration during
installation.
For detailed information about the PCI local bus, consult
the PCI specification.
Installation Requirements
The following items are required to install the 3C339 NIC:
■
PC with at least 640 KB of RAM and an 80486 or
Pentium processor
■
Sufficient memory to load the 3C339 NIC driver from
the network operating system
■
PCI bus slot that supports bus mastering
Book Page 2 Thursday, June 5, 1997 9:07 AM