Von Neumann architectureAA

Von Neumann architecture : 

Von Neumann architecture Also known as a ‘stored-program computer’

Basic parts : 

Basic parts Memory (RAM) Cpu(containing the control unit and ALU). Input(keyboard + mouse etc). Output(printer etc).

Memory : 

Memory

Control unit : 

Control unit A control unit takes in program instructions and translates them into a series of control signals which activate and control other parts of the computer

Arithmetic Logic Unit : 

Arithmetic Logic Unit Is a digital circuit that performs arithmetic and logical operations.

The von Neumann architecture computer performs the following series of steps: : 

The von Neumann architecture computer performs the following series of steps: Fetch the next instruction from memory at the address in the program counter. Add the length of the instruction to the program counter. Decode(or translate) the instruction using the control unit. Go back to step 1.

How the von Newman architecture relates to modern computers : 

How the von Newman architecture relates to modern computers The cpu “sits” ontop of a motherboard which is then connected to the RAM and input/output. The difference between a von newmann’s architecture and modern computer architecture is that modern computers have a Northbridge and a Southbridge chipset.

CPU : 

CPU The heart of a computer is the central processing unit or CPU. This device contains all the circuitry that the computer needs to manipulate data and execute instructions. The CPU is amazingly small given the immense amount of circuitry it contains. From previous Classes We know that circuits of a computer are made of gates. (and, or, not gates) however Gates are also made of another tiny component called a transistor, and a modern CPU has millions and millions of transistors in its circuitry Image on the right shows how compact a CPU can be

CPU basic components : 

CPU basic components The CPU is composed of five basic components RAM Registers Buses ALU Control Unit Image on the right shows the basic diagram of how these components relate to each other

CPU basic components : 

CPU basic components RAM This component is created from combining latches with a decoder. The latches create circuitry that can remember while the decoder creates a way for individual memory locations to be selected. Diagram on the right shows a simple 16 bytes of CPU RAM

CPU basic components : 

CPU basic components Registers these components are special memory locations that can be accessed very fast. Three registers are shown in the diagram, the Instruction Register (IR), the Program Counter (PC), and the Accumulator.

CPU basic components : 

CPU basic components Buses These components are the information highway for the CPU. Buses are bundles of tiny wires that carry data between components. The three most important buses are the address, the data, and the control buses.

CPU basic components : 

CPU basic components ALU (The Arithmetic / Logic Unit ) This component is the number cruncher of the CPU. The Arithmetic / Logic Unit performs all the mathematical calculations of the CPU. It is composed of complex circuitry The ALU can add, subtract, multiply, divide, and perform a host of other calculations on binary numbers.

CPU basic components : 

CPU basic components Control Unit This component is responsible for directing the flow of instructions and data within the CPU. The Control Unit is actually built of many other selection circuits such as decoders and multiplexors. In the diagram, the Decoder and the Multiplexor compose the Control Unit.

Fetch And Execute Cycle : 

Fetch And Execute Cycle Fetch and execute cycle is The sequence of actions that a central processing unit performs to execute each machine code instruction in a program. At the beginning of each cycle the CPU presents the value of the program counter on the address bus. The CPU then fetches the instruction from main memory via the data bus into the instruction register. From the instruction register, the data forming the instruction is decoded and passed to the control unit which sends a sequence of control signals to the relevant function units of the CPU to perform the actions required by the instruction such as reading values from registers, passing them to the ALU to add them together and writing the result back to a register. The program counter is then incremented to address the next instruction and the cycle is repeated. The fetch-execute cycle was first proposed by John von Neumann

Fetch And Execute Cycle : 

Fetch And Execute Cycle Following Animation best explains the Fetch And Execute Cycle