1.1 The Central Processing Unit

The CPU (Central Processing Unit) is an essential component in any computer system.


The CPU processes data and instructions by continually repeating the fetch - decode - execute cycle.


CPU Components

The control unit directs the flow of data and information into the CPU.

It also controls the other parts of the CPU.

Stands for Arithmetic Logic Unit. It performs both simple calculations and logical operations in the CPU.

The registers are tiny storage spaces for temporary data inside the CPU. The registers are used during the FDE cycle.


Computer Architecture

The way a computer is designed and laid out is known as its architecture (like how a house is planned).

There are two main types of computer architecture. Von Neumann, which is used most often, and Harvard.

Von Neumann Architecture

Von Neumann architecture stores both instructions and data in memory, a revolutionary idea when it was designed in 1945.

Being able to store programs in memory allows computers to be re-programmed for other tasks - this will enable it to multitask and run several applications at the same time. Data input and output is another crucial feature of this architecture.

Harvard Architecture

Harvard architecture has separate storage areas and buses (data circuits) for instructions (Program memory) and data (Data Memory).

The control unit is the most crucial component of Harvard architecture. 

Questo's Corner

The CPU:

Describe the role of each CPU component:

a. Control Unit

b. Arithmetic Logic Unit

c. Registers


a. Which type of architecture do most modern computers use?

b. What is the most important feature of Von Neumann architecture?

c. How is Harvard architecture different than Von Neumann?

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