Central Processing Unit

Central Processing Unit (CPU)

  • The CPU is often referred to as the brain of the computer, as it carries out most of the processing inside the computer.

Core Components of the CPU

  • The CPU is made up of several key components: the Control Unit (CU), Arithmetic Logic Unit (ALU), and Registers.

Control Unit (CU)

  • The CU manages and controls the hardware devices in the computer, and conducts the fetch, decode, execute cycle.

Arithmetic Logic Unit (ALU)

  • The ALU handles all the arithmetic and logical operations. This includes basic computations like addition and subtraction, and logical operations like comparison of values.

Registers

  • Registers are small storage locations found in the CPU. These are used to hold data that is currently being processed.

Fetch-Decode-Execute Cycle of CPU

  • The fundamental operation of the CPU can be summarised in the Fetch-Decode-Execute cycle.

Fetch

  • In the fetch step, the CPU reads an instruction from memory.

Decode

  • During decode, the CPU translates the instruction into a format it can understand.

Execute

  • Finally, the CPU carries out the instruction in the execute step. After execution, it moves onto the next instruction.

Clock Speed

  • The clock speed of the CPU measures how many instructions the CPU can carry out per second. It is usually measured in gigahertz (GHz).

Multicore Processors and Parallel Processing

  • Some CPUs have multiple cores, allowing them to perform multiple tasks at once in a process called parallel processing.

Moore’s Law

  • Coined by Gordon Moore, Moore’s Law states that the number of transistors in a dense integrated circuit doubles about every two years, causing the processing power of computers to increase exponentially over time.

Processing Power and Performance

  • The performance and processing power of a CPU is influenced by several factors, including clock speed, number of cores, and the amount of cache memory.

CISC and RISC Architectures

  • Two types of processor architecture are CISC (Complex Instruction Set Computing) and RISC (Reduced Instruction Set Computing). CISC processors are capable of executing multi-step operations or addressing modes within one instruction set, while RISC processors execute one operation per instruction cycle.

Heat Dissipation

  • As CPUs work, they generate heat due to the electrical energy consumed. Efficient heat dissipation methods, like cooling fans and heat sinks, are required to maintain the performance and lifespan of the CPU.