Bus Interface Unit

The bus interface unit is the part of the processor that interfaces with the rest of the PC.
Its name comes from the fact that it deals with moving information over the processor
data bus, the primary conduit for the transfer of information to and from the CPU. The
bus interface unit is responsible for responding to all signals that go to the processor,
and generating all signals that go from the processor to other parts of the system.
It receives instructions & data from main memory to be processed and operations. After
the operations are processed it then sends back the information (processed data) to the
cache. It also receives the processed data to send it to the main memory.