Main structure of a Computer

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Here we will discuss the internal structure of a computer. For this we begin with a traditional computer with a single processor which employs a microprogrammed control unit and then examine a typical multicore structure.

Simple single-processor computer provides a hierarchical view of the internal structure of a traditional single-processor computer. There are 4 main structural components;

Main components of structure of a Computer

The 4 main structural components of a Computer is given bellow;

Central processing unit (CPU)

CPU controls the operation of a computer as well as performs its data processing functions. CPU is often simply referred to as processor.

CPU is the major part of the structure of a computer. To learn more about CPU read out the article what is CPU? What are the major parts of CPU?

Main memory

Function of main memory is to stores data. Main memory is also an integral part of the structure of a computer. Lets see the memory hierarchy of a computer.

computer memory, primary storage device, secondary storage device, primary and secondary memory

There are different types of memory which we have discussed in details at types of computer memory | Primary and secondary storage devices.

Input/Output (I/O)

It moves data between the computer and its external devices. To learn more read out different computer peripherals with details of them.

System interconnection

These are actually some mechanism which provides for communication among CPU, I/O, main memory etc.

The most common example of system interconnection is system bus which is consisting of a number of conducting wires with which all the other components attach.

Not only that, there may be more of each of the aforementioned components of a computer. Traditionally there has been just a single processor for almost all the computer.

But in recent years, there has been increasing use of multiple processors with a single computer.

Structural components of a CPU

The most interesting and complex component of a Computer is the CPU. Its major structural components are given bellow;

Control unit

Control unit controls the operation of the CPU and hence the computer.

Arithmetic and logic unit (ALU)

ALU performs the computer’s data processing functions.


Register provides storage which lies internal to the CPU.

CPU interconnection

These are also some mechanism which provides for communication among the control unit, ALU as well as registers.

However, there are several approaches to implement of a control unit. Most common approach is the microprogrammed implementation.

Here a microprogrammed control unit operates by executing microinstructions which define the functionality of the control unit.

Multicore computer have multiple processors. When these processors all reside on a single chip then the term multicore computer is used.

Each processing unit is called a core. To clarify the terminology, we will use the following definitions.

Terms related to multicore computer

Central processing unit (CPU)

CPU is that portion of a computer which fetches and executes instructions. CPU consists of an ALU, a control unit, and registers. It is simply called processor in a system with a single processing unit.


Core is an individual processing unit on a processor chip. This core may be equivalent in functionality to a CPU on a single CPU system.

Some other specialized processing units including one optimized for vector and matrix operations, are also referred to as cores.


Processor is actually a physical piece of silicon which contains one or more cores. Processor interprets and executes instructions. When a processor contains multiple cores, it is referred to as a multicore processor.

However the most prominent elements on the motherboard are the chips which is a single piece of semiconducting material, typically silicon, upon which electronic circuits and logic gates are fabricated.

The resulting product is called as an integrated circuit.

All the motherboard contains a slot or socket for the processor chip that is typically contains multiple individual cores, in what is known as a multicore processor.

Not only that, there are also slots for memory chips, I/O controller chips as well as other key computer components.

For desktop computers, expansion slots enable the inclusion of more components on the expansion board.

In this way, a modern motherboard connects only a few individual chip components, with each chip containing hundreds of millions of transistors.

Functional elements of a core

In general terms, the functional elements of a core are given bellow;

Instruction logic

Instruction logic includes the tasks which is involved in fetching instructions as well as decoding each instruction to determine the instruction operation and the memory locations of any operands.

Arithmetic and logic unit (ALU)

ALU performs the operation which is specified by an instruction.

Load/store logic

This manages the transfer of data to and from main memory via cache.

However, I think you have got a brief idea about the main structure of a computer. You can share your opinion in the comment section bellow.

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