Explain Von Neumann Architecture?

Hey guys, In today’s blog we’ll discuss the topic of “Explain Von Neumann architecture”


The Von-Neumann Architecture or Von-Neumann model is also known as “Princeton Architecture”. This architecture was published by the Mathematician John Von Neumann in 1945.

von Neumann architecture

It is a design model for modern computers which has a Central Processing Unit(CPU) and the concept of Memory which is used for storing both data and instructions. This architecture implemented the stored program concept in which the data and instructions are stored in the same memory. This architecture consists of a Control Unit, CPU, Arithmetic and logic unit(ALU), Register, I/O(Input Output Devices), and Memory unit.


  1. CPU(Central processing unit)
    • CU(Control Unit)
    • ALU(Arithmetic and logic unit)
    • Registers
      • PC
      • IR
      • AC
      • MAR
      • MDR
      • BUSES
  2. I/O Device

1. CPU

A CPU is a part of the computer system, where the CPU is responsible for executing the bulk of data and programs in a specific manner. A CPU is the brain of the computer and it consists of an arithmetic and logic unit(ALU), a Control Unit(CU), and various registers. The CPU is also known as the central processor or microprocessor of the computer.

a) CU

A CU is the control unit that is the part of a CPU. The CU is the circuitry that does the direct operations in the main memory of the computer system and it directs the input and output flow. The control unit determines the sequence in which computer programs and instructions are executed. It works by receiving input information and it converts it into control signals.

b) ALU

ALU is an arithmetic and logic unit that performs all the mathematical operation on binary numbers and it is an important component of the CPU(Central Processing Unit), Which carry the actual execution of instructions.

The ALU is allowed to do some operations like addition, subtraction, multiplication, and division, etc. The data is transferred to ALU from the storage unit when it is required. After processing, the output is returned to the storage unit for further processing on getting stored.


It is also an important part of a CPU. The registers are temporary storage where it is built in a CPU and it also provides a better storage speed. In registers, all the data are processed after that data are stored in the registers.

There are some internal registers are:

i) IR(instruction registers)– The instruction registers or current instruction registers(CIR) means that the hardware element that holds and receives the instruction is extracted from the memory of registers.

ii) PC(Program counter)– The program counter register is those registers where the computer processor contains the address of the next instruction to be executed. This register
is also known as an instruction pointer.

iii) AC(Accumulator)– The accumulator register is a type of register included in a CPU. It holds the intermediate storage of arithmetic and logic data in a computer’s CPU. Intermediate results of an operation are progressively written to the accumulator(AC)

iv) MAR(Memory Address Registers)– The memory address register is a CPU register That contains the main memory of data and instructions or It contains a portion of the address that is used for the calculation of a complete address, And it also holds the memory location of data that needs to be accessed.

V) MDR(Memory Data Register)– The memory data register is also known as memory buffer register(MBR), This is the register of the central processing unit that stores the data being transferred to and from the immediate access storage

VI) BUSES- In computer architecture, the bus means it is a communication system that is used to connect the computer components from one part to other parts of the system. A computer bus is either parallel or serial.

Parallel buses transmit data across multiple wires. Serial buses transmit data one bit at a time.

#Buses consist of three parts are:

  • Address Bus: The address bus is a computer-based architecture that is used to transfer the data between the storage and the processor.
  • Data bus: A data bus is also known as a processor bus and it allows for the transferring of data from one part of the computer to another on a motherboard or between two computers.
  • Control bus: A control bus is a part of the system bus, It carries the signal from the CPU which helps to communicate with the devices that are contained within the computer.

2. I/O Devices

An I/O or input/output device is a Hardware device that is used to communicate with a computer, whereas the Input device is used to provide data to a computer for entering data and programs in a computer system.

On the other hand, Output devices are those devices that receive information from the computer and carry out the data that has been processed by the computer to the user. An Output device display
information on the screen(monitor) or the printer.

Examples of Input Devices: Keyboard, Mic, Mouse, Joystick, etc., and much more.

Examples of Output Devices: Monitors, Printers, Headphones, etc., and much more.


A memory unit is part of the computer system it is used to store all the data and information in a storage system permanently. This memory stores the binary digit(0&1) information in groups of bits. In the computer system, it is the place where the computers hold data and programs which are in use.

Memory units consist of two types:

1. Primary Memory- Primary memory includes RAM(Random Access Memory) which is volatile in nature.

2.Secondary Memory- In secondary memory include ROM(Read Only Memory) which is Non-volatile in nature

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