If you like to think of writing a program as analogous to preparing an elaborate meal, then for any given cooking appliance, such as a microwave oven or electric stove (the hardware) there are a range of processes. These processes — for example, steaming, frying, boiling — are analogous to the instruction set which can be implemented by the CPU. The various ingredients that can be handled by a process are the instruction’s data. Such data may lie in an internal register or out in the Data store. There are several different ways of specifying the effective address (ea) of an operand. These are known as address modes.