A von Neumann Architecture computer has five parts: an airthmetic-logic unit, a control unit, a memory, some form of input/output and a bus that provides a data path between these parts.
A von Neumann Architecture computer performs or emulates the following sequence of steps:
Merchant computers never have a purse von Neumann architecture. Most computers add another step to check for interrupts, electronic events that could occur at any time. An interrupt resembles the ring of a telephone, calling a person away from some lengthy task. Interrupts let a computer do other things while it waits for events.
Von Neumann computers spend a lot of time moving data to and from the memory, and this slows the computer. So, engineers often separate the bus into two or more busses, usually one for instructions, and the other for data.