Control Data Cyber 170 State Hardware Reference Manual page 25

Major System Component Descript~ons
Central Memory (CM)
The CM (figure 1-2) consists of the following items.
Eight memory banks.
Memory ports.
Distributor.
The CM is a dynamic random access memory organized into eight independent banks.
A
portion of CM can be reserved for use as extended memory.
This portion,
which is called unified extended memory (UEM), is referenced by the RAE and FLE
registers. The UEM operates in either 24-bit format standard addressing mode
or 30-bit format expanded addressing mode.
One memory port has a queuing buffer.
The ports are located in the central
processor cabinet.
The distributor resolves port conflicts and multiplexes data from ports to the
storage unit.
It includes the error correction code (ECC) generator, SECDED,
and partial-write logic. The distributor is located in the central processor
cabinet
.