Compaq AlphaServer GS80 User Manual page 25

The CPU, memory, power, and I/O riser modules plug into the backplane.
Because of the orientation of the QBB backplanes, the modules are situated
differently in the front and rear of the system box. See Section 3.5 for more
information.
The switch interconnect on the backplane allows any processor to access any
memory on the QBB. The backplane also provides power to the modules.
–
Global port module
—
Directory module
˜
CPU module
™
Memory module
š
I/O riser modules
›
Clock splitter module
œ
Power system manager (PSM) module

Main power module
ž
Auxiliary power module
GS160/320 System Overview 2-9