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A Concise Introduction to Computing

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Jeff Zod is an Information Technology expert.He enjoys developing software, surfing the web, hacking, and securing computer systems.

Computing Devices

Computing Devices

Computing Devices


A computer is a machine which can be programmed to carry out logical and arithmetic computations sequentially and automatically. It does this by accepting user-defined input and then processes the input to produce output. The components of a computer fall into two categories, namely hardware and software. The hardware consists of the tangible or physical components of the machine, such as the mouse, keyboard, monitor, hard disk and the system unit. The software consists of a set of instructions that perform various functions, examples of software include systems software and application software.

Computers are ubiquitous in the modern world. Various industries, such as banking, manufacturing, education, and medicine, are currently using computers to increase productivity. Computers are utilized to automate manual tasks deemed too dangerous for humans or those that require very precise calculations. Computers process data at high speeds and are thus used in preforming millions of calculations per second.

Computer Skills

Classification of computers.


Supercomputers are the fastest and the most expensive modern computers. Supercomputers perform billions of calculations every second. They are owned by governments, corporations, universities and research institutions so they can perform complex tasks, such as engineering, generating complex graphics, and stock analysis

Mainframe Computers

These are large computers capable of processing data at very high speeds. They can compute millions of instructions per second. They are also expensive. They are mostly utilized by governments, companies, and universities.

Personal Computers

Personal computers are often called PCs. They are the most popular and they are relatively affordable. They can be used by either one user at a time or networked to be used by several users.

Personal Computer

Personal Computer

Personal Computer

Characteristics of Computers.

  • Speed

Computers process data onto very high speeds.

  • Accuracy

Computers are capable of processing data more accurately than humans due to sequential processing, i.e. they process data into logical steps.

  • Versatility

Computers are very versatile machines. They capable of performing multifarious tasks.

  • Consistency

Computers are capable of processing data consistently due to sequential processing and because computers do not make mistakes.




How computers are organized

A typical computer system is composed of a central processing unit (CPU), an input unit, an output unit, and a storage unit. The central processing unit consists of the arithmetic and logic unit and the control unit. The central processing unit is the most important part of a computer. It controls all the functions and the processes of the computer. The arithmetic and logic unit are responsible for all the arithmetic and logical functions. The function of the control unit is to control and coordinate the various components of a computer. The input unit provides an interface for the user to enter data that is to be processed. The function of the output unit is to store the result as output produced by the computer after processing. The storage unit is used to store data and instructions before and after processing.

Functions of a computer

A computer performs the following 5 functions:

  • Accepting data or instructions as input,
  • Storing the data and instructions,
  • Processing data as per the instructions,
  • Controlling all operations inside a computer,
  • Giving output.

Computer Memory

Computer memory is classified into two categories: primary memory and secondary memory. Primary Memory can be further subdivided into two subcategories: RAM and ROM.


RAM or Random-Access Memory is a memory structure that stores data temporarily. It is volatile, since its contents are erased when the computer is switched off.


ROM (Read Only Memory) is an enduring form of storage. Read Only Memory stays functional despite turning off; it contains boot instructions and the manufacturer’s instructions. Data stored in Read Only Memory is immutable.

Secondary memory

Secondary memory stores data permanently after switching off the power. Secondary storage devices are of two kinds; magnetic and optical. Magnetic devices include hard drives and optical storage devices are CDs, DVDs, flash drive, Zip drive etc.

Hard disks

Hard disks are a stack of metal plates sealed in a metal container. Hard disks have huge storage space ranging from 1 Gigabyte to 1 Terabyte. Data is re-writable on hard disks. Solid State Drives (SSD) are a form of a compact hard disk that can hold more data than the traditional hard disk.

Hard Disk

Hard Disk

Hard Disk

Compact Disk

Compact Disk (CD) is a flat circular portable disk having a data storage capacity of approximately 700 Megabytes. It is typically used to store application programs, operating systems, documents, movies, songs, and pictures.




Digital Video Disk

Digital Video Disk (DVD) looks like a CD except, it has a larger storage capacity and better clarity. They typically hold about 4 Gigabytes of data and they are typically used to store application programs, operating systems, documents, movies, songs, and pictures.




Input devices

These are used to enter instructions and data into a computer for processing or storage and to deliver the processed data to a user. Input/output devices are required for users to communicate with the machine. These devices are also known as peripherals since they are connected to the CPU and memory of a computer system. There are many input devices, but the two most common ones are a mouse and keyboard.





The keyboard is much like the antiquated typewriter keyboard but has more keys. The standard QWERTY layout of characters is maintained to make it easy to use the system. The additional keys are included to perform certain special functions. Keyboards log each key press and match the encoding of the key to produce the desired output.


A mouse is a pointing device that controls the movement of a cursor or a pointer on a screen. It derives its name from the rodent. When the user moves the mouse on a solid surface, the same movement will translate onto the screen.

Computer Mouse

Computer Mouse

Computer Mouse


A trackball is an input apparatus that is used to capture motion, much like a computer mouse. It has a ball that is rolled to move the cursor on the screen.


A touch-pad is a device that replaces the functions of the mouse on a laptop. It works by sensing the movement of a user’s fingers and pressure exerted by them.




Touch Screen

A touchscreen enables a user to input data by touching a sensitive screen using their fingers.




Light Pen

A light pen is an input device that uses a light detector to select objects on a screen. Users can also use their tablet or laptop like a notebook and take notes during meetings, if they wish.

Output Devices

The output device is used to display the results of processing. They convert the result into a form that is readable by humans; the output can be either be displayed on the screen or printed on paper.


This is also called a computer screen or a display unit. The monitor is much like a television screen.

Computer Software

System software

The main function of system software is to control and regulate the functionality of the hardware components in a computer. It frees applications from low-level abstraction such as transferring data from memory to disk or rendering text on display. System software typically consists of the operating system, such as Windows, Linux or UNIX and utilities such as file managers, text editors and disk formatters.

Application software

This software is used to accomplish specific tasks such as word processing, accounting, desktop publishing and browsing the internet. Application software may come as a program ,such as Recuva, or bundled with a suite, such as Microsoft Office, Microsoft Excel, etc.


Computers are ubiquitous in our lives. Everyone needs to have a working knowledge of computers to do well in the Information Age. They should be able to define what a computer is, explain its functions and identify its components. With this knowledge, users will be able to operate a computer much more effectively and even impress the IT staff

© 2018 J Zod

Computing for Beginners

J Zod (author) from Nairobi on November 01, 2018:

Thanks Marcus.

marcuscaine on October 28, 2018:

This is a very good reference guide for people who are not very tech savvy. Way to go!

J Zod (author) from Nairobi on August 13, 2018:

Hi Liz,

Your comments are really touching.You inspire me to write more ;)

You can bookmark my articles for future reference.

Liz Westwood from UK on August 13, 2018:

Great article. I feel like I should bookmark it for future reference. You have a real gift for explaining potentially complex terms in plain English that is refreshingly easy to understand.

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