The PE's would be fed instructions from a single master central processing unit (CPU), the "control unit" or CU. SOLOMON's CU would read instructions from memory, decode them, and then hand them off to the PE's for processing. Each PE had its own memory for holding operands and results, the PE Memory module, or PEM. The CU could access the entire memory via a dedicated memory bus, whereas the PE's could only access their own PEM. To allow results from one PE to be used as inputs in another, a separate network connected each PE to its eight closest neighbours.