The program memory serves basically as a place (1) instructions, the coded pieces of data (2) direct the activities of the control processing unit (CPU). A group of (3) related in- structions stored in memory is referred to as a program. The CPU "read" each instruction from memory a logically (4) sequence and "use" it to initiate program action. If the program structure is coherent and (5) , processing procedures produce intelligible and useful results.