CS-143 Lecture 05 on Von Neumann Architecture PDF
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Uploaded by WellConnectedPhiladelphia
GIFT University
Sajiya Tariq
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Summary
These lecture notes cover the fundamental concepts of von Neumann architecture. They detail the types of computers, the components of a CPU, and the fetch-decode-execute cycle. The notes focus on the structure of the von Neumann machine and its different parts.
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Application of Information and Communication Technology (CS-143) Lecture-05 Instructor: Sajiya Tariq Types of computers Historically there have been two types of computers Fixed programmed computers Limited operation Can not be programmed Stored p...
Application of Information and Communication Technology (CS-143) Lecture-05 Instructor: Sajiya Tariq Types of computers Historically there have been two types of computers Fixed programmed computers Limited operation Can not be programmed Stored programmed computers Multiple operation Can store programs to carry out different operations In this stored-program concept, programs and data are stored in a separate storage unit called memories and are treated the same von Neumann Architecture It is an architecture. (not a machine) Modern computer machines are designed upon von Neumann architecture. von Neumann Architecture Who invented this? In 1945 John von Neumann von Neumann Architecture von Neumann Architecture Main Memory: Store data and instructions Arithmetic Logic Unit: Does binary operations on data Control Unit: Understands(interpret) instructions and execute them. I/O Equipment: Input and output mechanism von Neumann Architecture CPU ALU In modern computers ALU and control Unit Arithmetic Logic Unit together is called CPU Registers Along with small stores of data. Control Unit von Neumann Architecture CPU Parts: Registers MAR Memory Address Register Holds memory address of data. MDR Memory Data Register Holds data that is being transferred to or from memory. AC Accumulator Holds intermediate arithmetic and logic results. PC Program Counter Holds address of next instruction. CIR Current instruction Holds current instruction. Register von Neumann Architecture CPU Parts: ALU (Arithmetic Logic Unit) It does operations over data. Arithmetic (Add or subtract etc.) Logic (AND, OR, NOT etc.) von Neumann Architecture CPU Parts: Control Unit It controls all the operations of ALU, memory and I/O. von Neumann Architecture CPU Parts: Bus Buses are responsible for transmission of data inside a computer. Address Bus Transfer address of data between CPU and memory. Data Bus Transfer data between CPU , memory and I/O. Control Bus Carries signals from CPU and control and coordinate all activites. von Neumann Architecture How a task is performed in CPU. We give instructions. Computer executes instruction by: Fetch Decode Execute Cycle Fetch Decode Execute Cycle Instructions are stored in main memory in binary form. 1. Fetch: Instruction is fetched from memory first. 2. Decode: Instruction is decoded. (What is task in instruction) 3. Execute: Instruction is executed then. This is repeated for every single instruction. Fetch Decode Execute Cycle Example: 000 1001 11 001 1101 00 Consider an instruction in memory at position 00 This instruction will fetched. 01 The fetched instruction will be decoded. 10 The decoded instruction will be executed. 11.
