Von Neumann Architecture
Computer Science: Cambridge International GCSE, topic 1.3.3
Von Neumann Architecture
All modern Central Processing Units (CPUs) are based on the Von Neumann architecture. The components of this architecture are:
Arithmetic and Logic Unit (ALU)
- The ALU performs all of the arithmetic and logical operations of the CPU, including:
- Addition and subtraction, multiplication and division.
- Comparisons such as whether numbers are equal or if one is greater than another.
- Boolean operations such as AND, OR and NOT.
Control Unit (CU)
- Sends out control signals to other parts of the CPU.
- Executes program instructions by following the fetch-decode-execute cycle.
- Made up of two key parts:
- The clock - coordinates the CPU's activity.
- The decoder - decodes program instructions.
Registers
- Registers are tiny amounts of super-quick memory within the CPU.
- Used to hold information needed for the CPU to work.
- Each register holds a specific piece of information.
Registers of the Central Processing Unit (CPU)
Registers that have a predetermined purpose in the central processing unit are known as special purpose registers.
Program Counter (PC)
- Holds the memory location address of the next instruction to be performed by the CPU.
Accumulator (ACC)
- Holds the result of calculations and operations performed by the arithmetic logic unit (ALU).
Memory Address Register (MAR)
- Holds the address of the location in memory where data is to be retrieved or stored.
Memory Data Register (MDR)
- Holds the data that has been retrieved from memory, or that is about to be stored in memory.
Test yourself on Von Neumann Architecture
This is the common architecture for what feature of computers?
Modern CPUs are based on the Von Neumann architecture. What does CPU stand for?
Which of the following are components of the Von Neumann architecture?
Which of the following are examples of Boolean operators?
What is the purpose of the program counter?