Components of a Computer

Computer Components:

A computer is made up of hardware and software. Hardware comprises a group of physical elements or the physical parts and components in a computer like a mouse, keyboard, monitor, computer data storage, and system units, for example, sound cards, graphic cards, motherboard, memory, and chips. It also consists of a hard drive disk or HDD. Hardware is physical in the sense that you can touch them.

Computer Hardware:

Computer hardware consists of input devices, CPU, and memory.

History of Computers & Generations of Computers Explained on YouTube:

Input devices:

When we talk about input devices in a computer, they are the peripherals or pieces of hardware equipment used to provide as well as control signals to the information processing system. Input devices are used to translate data so that the computer is able to understand it and work with. In essence, input devices transform data from the form understandable by humans to the form that a computer understands. The common input devices are:

  • Keyboard.
  • Scanner.
  • Mouse.
  • Webcam.
  • Microphone.
  • Touchscreen touchpad.
  • Cameras.
  • Gamepad.
  • Digital camera.
  • Joystick.
  • Pen input.
  • Electronic Whiteboard.
  • Video capture hardware.
  • Trackballs.

CPU – Central Processing Unit:

This stands for central processing unit and it’s considered the brain of a computer. CPU takes care of all functions and processes. In terms of computing power, the central processing unit is the most crucial elements of the system. There are three main parts in a CPU.

Arithmetic logic unit -ALU:

This hardware executes the arithmetic as well as logical operations. When talking of arithmetic calculations, they are calculations like addition, multiplication, subtraction, and division. Logical operations involve comparing letters, numbers, and special characters.

Control unit – CU:

This hardware works to control and coordinate the components of a computer.

  • It reads the code for the subsequent instruction to be executed
  • It increases the counter of the program to enable it to point to the next instruction
  • It reads the data required by the instruction from the memory cells
  • It provides the necessary data to register or arithmetic logic unit
  • If the instructions require specialized hardware or arithmetic logic unit to complete, the control unit instructs the hardware to execute the requested operation.


A register stores the next executable data; it is a fast storage area that allows the next execution to take place effectively.


A computer has primary and secondary memory. Random Access Memory (RAM) is a memory found on the computer and it is used to store data temporarily to allow the processor access it as and when needed. An important thing to point out is that the data stored in the Random Access Memory scheme is erased when power supply to the storage is cut off or turned off. The storage of data in RAM is random and the access by the processor is also done randomly. The reason is it called random access is because a user can directly access any given memory cell if they know the column and row that intersect at the particular cell.

ROM – Read Only Memory:

Apart from RAM, primary memory also comprises Read Only Memory (ROM). This is a permanent type of storage meaning it remains active even when the power supply is cut off or turned off. So, the data is not erased. ROM devices don’t allow modification of data stored in them.

Secondary memory is used to store data and programs permanently meaning that even when power is cut off, the data is retained. An example of secondary memory is the hard drive (HD).  Hard disk drive stores and provides access to huge amounts of data quickly on the surface that’s electromagnetically charged. Another example of secondary memory is optical disk drive (ODD). This is a disk drive that utilizes laser light to read and write data within optical discs. While some optical disk drives may only read data, modern drives are both readers and recorders and they are popularly known as writers or burners. Common types of optical media are Blu-ray discs, DVDs, and compact discs. These media can be read as well as recorded by the drives. Generally, there are three kinds of optical media and they are CDs, DVDs, and Blu-ray discs.

Flash disks are new storage modules that are designed of flash memory chips. Although they aren’t disks as such, they are given the name disks because access of data from them is done as if it were on a hard drive.

Output devices:

These are devices or computer hardware used to relay or communicate the results obtained from the data processing activity from the information processing system or the computer. The output device converts the information to a form that is readable by humans. Example of output devices are:

  • Monitor.
  • Printer.
  • Computer output microfilm.
  • LCD projection panels.
  • Speakers.
  • Plotters.
  • Projectors.

History of Computers     Father of Computer       Software       Generations of Computers

Computing Machines       Artificial Intelligence         First Mechanical Computer   

Turing Machine                       Colossus         Z1           First Computer Ever Made

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