User`s guide

The VAX 6000 Platform Overview
1.5 XMI Backplane and Card Cage
The XMI high-speed system bus interconnects processors, memory
modules, and I/O adapters. The XMI card cage has 14 slots and a
maximum bandwidth of 100 megabytes per second.
Figure 1–4 XMI
CIXCD
KDM70
XMI
Processors
Memory
msb-0316A-90
XMI CARD CAGE
DEMNA
FRONT
The XMI is a limited-length, pended, synchronous bus with centralized
arbitration. The XMI bus can process several transactions simultaneously,
making efficient use of the bus bandwidth. The bus includes the XMI
backplane, the electrical environment of the bus, the protocol that nodes
use on the bus, and the logic to implement this protocol.
The XMI backplane and 14-slot (nodes 1 through E) card cage are located
in the upper third of the cabinet on the right side, as viewed from the front
of the cabinet. A clear latched door protects the components housed in the
XMI card cage and helps to direct the airflow over the modules. Indicator
lights on the XMI modules can be viewed through this clear front door.
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