Hello friends, on this topic we will discuss what is a computer system and its parts.  The main points we are discussing of  this topic are

We all know that a computer is the most essential part of our technical life. It uses engineering works, scientific works, schools, colleges, universities, offices, business purposes, hospitals, all other working sectors, and also our personal lives. It changes our life simple and quicker. It is the most job opportunities sector all over the world. Computer increases our job opportunities day by day. We can make our future from it. Because of this sense, we have to learn the best of the best ideas and knowledge about computer technologies. Having knowledge about computer technology or basics like what is a computer is helpful to our competitive exams or job interviews.

what is a computer system?

A computer is an electronic system that operates both mathematical and logical operations with large/small storage capability. It is a programmable system for processing, storing, and also displaying all kinds of instruction.                                                                                      

The full form of computer is   C – Common ,  O – Operating ,   M – Machine ,  P – Personal ,  U – Used for ,   T – Training ,  E – Education,   R – Research.

Who invented the computer?

The very first computer(calculator) was made in China and it’s called “ABACUS”.In 1617 John Napier introduced Napier’s bones for calculation.

In 1642 Blaise Pascal invented PASCAL’S calculator. In 1801 Joseph Jacquard introduced punched cards that were used in cotton looms and weaving patterns to store data. It is treated as an essential part of the all-time computing hardware.

In 1823- 1833, British Mathematician Charles Babbage conceived of the analytical engine. Charles Babbage is called the father of the computer. A machine with memory and calculating which could be programmed.

The analytical engine was never built-in in 1991. A different engine depends on an easier A Babbage structure was made. It performs the same as Babbage thinks.

A British mathematician called Alan Turing and cryptanalyst tried to build a device that could solve all problems that were presented in a bundle of data.

A German engineer Konrad Zuse made series of systems for his arithmetics. Zuse’s Z3 Was the earliest perfectly performing, program-managed system. But war isolated Zuse and his work wasn’t widely known.

In 1941 American physicist John Mauchly and engineer J. Presper Eckart made the ENIAC. It was much faster than previous machines but had no memory to store programs and needed to be tediously rewired for each problem.

After the war ENIAC was declassified and unveiled to members of the scientific community. The Manchester Baby was a prototype of just such a stored-program computer. Build by Manchester university.

It ran a program from memory on June 21, 1948.A patented for the computer has never been awarded. Konrad Zuse tried in the 1940s but his 1st patent application was denied for being vague and his second was delayed for decades.

In 1964 a patent on the ENIAC was awarded to its investors Eckart and Mauchly.

The Eckart-Mauchly computer corporation had been acquired in 1950 by the corporate that became Sperry Rand. Sperry Rand now demanded royalties from anyone building a computer.

When competitor Honeywell refused, a fierce legal battle ensured. But Honeywell’s lawyers uncovered a touch-known fact. In 1940, John Vincent Atanasoff, an assistant professor at Iowa State, had shown his computing machine to a visitor John Mauchly.

The general concept of the computer was not patentable. So friends who invented the computer? The answer is not one person, but many influenced and inspired by each other.

What are the Categories of Computers?

You know friends there are 3 types categories of computers, these are

(a) Based on Mechanism
(b) Based on the size
(c) Based on the purpose

Based on mechanism

There are 3 types of computers based on mechanism,

(a) Analog Computer
(b) Digital Computer
(c) Hybrid Computer

(a) Analog Computer

“An analog computer might be a category of a computer system that utilizes the regularly unstable condition of physical data like electrical, mechanical, or hydraulic capacities to figure the schedule is stored.”

Analog means regularity of identified volume just as an Analog clock allowances time utilizing the space well-traveled by the clock around a dial. They react in a predefined way to changes in the specified quantities.

It accepts input data in continuous form and output is obtained in the form of graphs. It is faster than the digit computer but can give an accuracy of not more than 99%. These computers are suitable for use as controlling devices in factories, military forces, and weaponry, etc.

Examples- Speedometers, Thermometers, Analog clock, Voltmeters, Wall clock, and Flight simulators for training pilots.

Advantages – (a) Devices that media represents (b) Store images (c) Sound, motion, pictures, etc.

Disadvantages – (a) Analog computers can have a really wide selection of complexity. (b) Slide rules and monographs are the only while naval gunfire control computers and enormous hybrid digital/analog computers are among the foremost complicated. (c) Very complicated for containing output for the users sometimes.

(2) Digital Computers

Digital computers taking in the form of numbers, letters, and special characters stock it, operates it, and provide the output in the form of numbers, letters, and unique characters.

Like these computers always operates information (consisting of text, sound, graphics, and video) into a digital value(in 0’s and 1’s) information continues in the design of pulses.

A computer that performs calculations and logical operations with quantities represented as a digit, usually within the binary numeration system of “0” and “1”.

“Computer has capacities of settle issues by handle data suggested in various structure. By manipulating combinations of binary digits (“0”, “1”). It can perform mathematical calculations, organize and analyze data control industrial and other processes, and simulate dynamic systems like global weather patterns. These types of computers are lots of problems oriented”.

Examples- IBM PC, Apple Macintosh, Calculations, Digital watches desk calculations, Electronic computers.

Advantages – Digital computers have the capabilities of adding, subtracting, multiplying, dividing, and comparing. These computers provide highly accurate results.

(3) Hybrid Computers

A hybrid computer may use or produce analog data or digital data. It allows a regularly fluctuating absorption, which is then transformed into a bundle of disconnected values for digital preparing. Both and hybrids are special-purpose computers. It uses a special device called MODEM to convert analog signals to digital signals and vice-versa.

The full form of Modem is modulator and demodulator. Information is often transferred to geographically dispersed areas through computers by the utilization of MODEM. A computer system is that acts both analog and digital data. A hybrid computer may be a computer that accepts analog signals, converts them in digital form.

Examples – (a) Hybrid computer is that the computer utilized in hospitals to live the heartbeat, and other tests of the patient. (b) Devices used in petrol pumps. (c) Hybrid machines are generally used in scientific applications or in controlling industrial processes.

Based on the size

There are five types of computers based on size. These are (a) Supercomputer (b) Mainframe computer (c) Mini computer (d) Microcomputer (e) Portable computer

(a) Super computer

They are very fast and powerful machines. It works at speed of 10 MIPS (MILLION INSTRUCTIONS PER SECOND). They are very expensive because they are not used in general applications. They utilized for scientific reasons. Example- Gray and CDC cyber.

(b) Mainframe computer

They are using for general computing. It helps in business and engineering. They are very fast and will process information at about 10 MIPS. These are very costly. Not easily found in general design offices.

(c) Minicomputer

They are developed in the 1960s resulting from advances in microchip technology. They are and less expensive than mainframe computers and supercomputers. It runs at several MIPS and can support 5-20 users. It is a low cost but high performance.

(d) Microcomputers

They were invented in the 1970s. They are generally used for home computing. They dedicate a data processing workstation. Advances in technology have improved microcomputer capacities, resulting in the explosive growth of personal computers in the industry. The microcomputer can be divided into some types –

(a) Desktop – It is a personal computing device and it is designed to fit on a physical office desk small office. It includes the keyword, monitor, mouse, CPU, ups, sound, etc. All desktop computers include built-in MODEM and storage devices.

(b) Laptop – The laptop is a personal computer and is designed for mobile use. It’s small light enough to sit on a person’s lap while in use. It includes a display, keyboard, pointing device, touchpad, trackpad, sound speaker, the battery in a small unit. It is portable we can take anywhere this laptoP.

(c) Palmtop – Palmtop is a small computer that fits on our palm. Related to large-size computers palmtops are extremely limited. It can include our smartphones. IT uses a pen rather than a keyboard for input. It is called handheld computers or PDAs (personal digital assistance).

(e) Portable computer

Portable computers can be carried from one place to another in the form of a briefcase or diary. It includes Laptop, Notebook, and personal a digital assistant (PDA).

Based on the purpose

There are two types of computers based on purpose. They are

(a) Special-purpose computers – They are designed to perform a specific task. They perform a task for which they are designed very efficiently.

(b) General purpose computers – It is one that can be used for a variety of applications. They can act all kinds of work. Its creativity enables the execution of a program at almost any time. They are used in business applications, home use, offices, etc.

Characteristics of computer


Computers are very accurate. Computers maintain accuracy within a millisecond, microsecond, nanosecond, picosecond, or any level of required precision. These are also accurate up to many decimal places than mathematical calculations.

They do make mistakes but seldom. This is because of their physical circuit. Even if they make mistakes, it might be because of the faulty programs, some mistakes made while feeding in the data, or a poorly designed system. The highly efficient error- detecting techniques of the computer prevent it from showing false results.


The computer was initially invented as a very high-speed calculator. This helped in completing many scientific projects that were previously impossible. The speed of a personal computer is measured in terms of Megahertz. That is millions of clock cycles generated by microprocessor clock in one second.

Most modern microcomputers are rated from 300 Megahertz to 2 Gigahertz. A common 800 Megahertz computer system takes a little portion of a second to finish one round.

Actually, a few clock rounds are needed to carry a single piece of information from storage decoded and executed. The speed of workstations mainframes and high-speed personal computers are measured in terms of millions of instructions per second.

These computers operate in the range of 20 to 1000 MIPS. The speed of a the supercomputer is measured in terms of floating-point operations per second(FLOPS). Floating-point numbers consist of very small or very large numbers.


An important feature of a computer is reliability. The outcomes of computer actions are very much trustable and correct. High reliability is because a computer works electrical pulses that rarely fail to convey the correct information.

The reliability of computers is maintained especially in repetitive tasks. Further the error checking systems are built into a computer to reduce the chance of errors. Organizations provide backup computers that automatically take over in case the main computers fail.

Recovery systems are implemented to further strengthen the reliability of data. It can be run for years and years without any loss of data or any problem.


Another feature of a computer is a large memory. Computer memory is utilized to keep information and data temporarily or permanently. Secodary memory is generally specified to as random access memory.

This is used to temporarily store programs that are currently executing the computer system. The contents of the ram are erased when the power is off. Actually, the capacity of temporary memory is assessed in the style of kilobytes and megabytes.

Most modern computers are special graphics computers have large memories in multiples of gigabytes. Permanent memory is used to permanently store large repositories of data user programs applications like Ms office and operating systems like Windows or Linux.

An example of permanent storage is a hard disk. The programs stored on permanent memory is available when we switch on the computers. A large amount of data can be stored on permanent storage devices.

Logical decision making

Computer memories have another advanced feature to dynamically access any data irrespective of its storage location. Apart from computations, a computer has the ability to make decisions. The computer has unique circuits to functioning logical actions.

Logical operations include comparisons such as numbers are equal to greater than or less another number. Trust in the outcomes of logical actions a computer might proceed correct operations. The computer is also capable of comparing text images and even audio.

The decision-making capabilities of the computer have led to the invention of artificially intelligent machines.


A computer is a versatile system or device. It is capable of solving a variety of problems in any type of task provided the activity could be put into logical steps. The use of personal computers has considerably grown in the fields of communications multimedia scientific research, designing, engineering, education, and entertainment.


Another remarkable feature of computers is their ability to perform operations automatically. When the computer is switched on it automatically executes instructions to check all peripheral devices leads the operating systems and provides an interface to the user without human interaction.


A computer is a diligent device or system. It never feels tiredness, fatigue, lack of concentration, or lost interest. You can complete different jobs or a single task repeatedly without losing position.

Limitations of computer

Computers are widely used due to their versatility. But computer systems have more limitations. These are

(a) Lake of intelligence – The first limitation of computers is their lack of intelligence. Although a computer can perform logical operations at a very first speed but it is unable to think like a human. Presently computers cannot tell the fragrance of a flower or have no aesthetic sense.

(b) Need proper environment for smooth operations – Computers need a proper environment for smooth operations. These can only operate in a dust-free environment under certain temperature conditions.

(c) Need for special language – Computers can only understand binary codes. That 0’s, 1’s, and their combinations. These codes aren’t commonly employed by humans. Special software interpreters and compilers are used to convert natural languages to computer understandable codes. Despite these limitations the fame and applications of computers are greatly developing.

Main parts of computers

The main parts of a computer are two types. Without these, we can’t run a computer. These are – (a) Hardware (b) Software

Hardware refers to the physical components of a computer. Major parts of hardware are monitor, CPU, keyboard, etc. CPU is the primary component of a computer system.

CPU is divided into three major parts, (a) Control unit (b) Arithmetic logic unit (c) Memory unit.

(a) Control unit

It manages the process of every component’s actions of the computer system. It collects the information’s from the memory clarifies them and guides the activity of the system.

The control unit converts the user’s input that is received from a keyboard, or mouse, or any other input device and converts them into signals, and then send back to them to to the ALU unit.

It utilizes clock inputs to control the arrangement of the information. Its quickness is the frequency of the information preparation and it is judged in megahertz.

(b) Arithmetic Logic Unit

This is the part of the CPU system that carries out arithmetic and logic operations. An ALU performs basic arithmetic. The arithmetic operations are addition, subtraction, multiplication, and division.

It also works as a logical process as the similarity of codes like as NOT, AND, OR. All data in a the computer system is kept in the structure of binary numbers i.e “0” and “1”.

(c) Memory unit

The memory unit stores the data, instructions and sends the stored information to all the other units of the computer whenever it needs. It is called as the primary memory or RAM(RANDOM ACCESS MEMORY). All input and output are transmitted through the main memory.

There are two kinds of memory- (1) Primary memory (2) Secondary memory.

(1) Primary memory – Primary memory selects any part of memory when the user wants to save the data in memory but they may not be store permanently on the location.

(2) Secondary memory – It is useful to store external storage and media such as a DVD drive, Hard disk, Memory card, memory sticks like a pen drive.

ROM(READ ONLY MEMORY) is a component of secondary memory.

ROM – It is a memory location that offers huge ROM is permanent types of standards to save data. But it works with read-only operation.No data loss happen whenever power failure occurs during the ROM memory work in computers.

PROM – It is a programmable read-only memory that can be read as many times as we want but cannot be modified the data.

EPROM – It is the erasable programmable read-only memory but it has to be passed through ultraviolet light to get erase the data, so it is not in use now.

EEPROM – It electrically erasable programmable ROM.Similar to the EPROM but it uses electrical beans for areas the data.

Software indicates to the directions which prepare the computer system perform. The software should be stored in the secondary memory device and loaded to the primary memory and when needed broadly we will classify software in two types-

(1) System software – The system software consists of low-level programs that interact with the computer at a very basic level.

Example – Printer software, Scanner software. Some of the operating systems to use worldwide are Windows operating systems, APPLE Mac operating system, Linux software which is free to use.

(2) Application software – The application software consists of programs that are required for a user. The application software is also called End-user programs.

Examples – Emails, Word processors, spreadsheets, games, etc.

So friends, here we have discussed what is a computer system and its parts, what are the categories, characteristics, limitations, inventors of computers, parts of computer, hardware and software etc. Hope you all understand my language. If you need more information about it feel free to contact us. If you like this tutorial share it. To learn more you can see the next blog. Thanks for your valuable time. If you like this topic like, comment and share.

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