Basis of computer and their evaluation

30/04/2020 2 By indiafreenotes

Today’s world is an information-rich world and it has become a necessity for everyone to know about computers. A computer is an electronic data processing device, which accepts and stores data input, processes the data input, and generates the output in a required format.

The purpose of this tutorial is to introduce you to Computers and its fundamentals.

Functionalities of a Computer

If we look at it in a very broad sense, any digital computer carries out the following five functions:

Step 1: Takes data as input.

Step 2: Stores the data/instructions in its memory and uses them as required.

Step 3: Processes the data and converts it into useful information.

Step 4: Generates the output.

Step 5: Controls all the above four steps.

Advantages of Computers

Following are certain advantages of computers.

High Speed

  • Computer is a very fast device.
  • It is capable of performing calculation of very large amount of data.
  • The computer has units of speed in microsecond, nanosecond, and even the picosecond.
  • It can perform millions of calculations in a few seconds as compared to man who will spend many months to perform the same task.


  • In addition to being very fast, computers are very accurate.
  • The calculations are 100% error free.
  • Computers perform all jobs with 100% accuracy provided that the input is correct.

Storage Capability

  • Memory is a very important characteristic of computers.
  • A computer has much more storage capacity than human beings.
  • It can store large amount of data.
  • It can store any type of data such as images, videos, text, audio, etc.


  • Unlike human beings, a computer is free from monotony, tiredness, and lack of concentration.
  • It can work continuously without any error and boredom.
  • It can perform repeated tasks with the same speed and accuracy.


  • A computer is a very versatile machine.
  • A computer is very flexible in performing the jobs to be done.
  • This machine can be used to solve the problems related to various fields.
  • At one instance, it may be solving a complex scientific problem and the very next moment it may be playing a card game.


  • A computer is a reliable machine.
  • Modern electronic components have long lives.
  • Computers are designed to make maintenance easy.


  • Computer is an automatic machine.
  • Automation is the ability to perform a given task automatically. Once the computer receives a program i.e., the program is stored in the computer memory, then the program and instruction can control the program execution without human interaction.

Reduction in Paper Work and Cost

  • The use of computers for data processing in an organization leads to reduction in paper work and results in speeding up the process.
  • As data in electronic files can be retrieved as and when required, the problem of maintenance of large number of paper files gets reduced.
  • Though the initial investment for installing a computer is high, it substantially reduces the cost of each of its transaction.

Disadvantages of Computers

Following are certain disadvantages of computers.

No I.Q.

  • A computer is a machine that has no intelligence to perform any task.
  • Each instruction has to be given to the computer.
  • A computer cannot take any decision on its own.


  • It functions as per the user’s instruction, thus it is fully dependent on humans.


  • The operating environment of the computer should be dust free and suitable.

No Feeling

  • Computers have no feelings or emotions.
  • It cannot make judgment based on feeling, taste, experience, and knowledge unlike humans.

The application of computers in various fields.


A computer has high speed of calculation, diligence, accuracy, reliability, or versatility which has made it an integrated part in all business organizations.

Computer is used in business organizations for:

  • Payroll calculations
  • Budgeting
  • Sales analysis
  • Financial forecasting
  • Managing employee database
  • Maintenance of stocks, etc.


Today, banking is almost totally dependent on computers.

Banks provide the following facilities:

  • Online accounting facility, which includes checking current balance, making deposits and overdrafts, checking interest charges, shares, and trustee records.
  • ATM machines which are completely automated are making it even easier for customers to deal with banks.


Insurance companies are keeping all records up-to-date with the help of computers. Insurance companies, finance houses, and stock broking firms are widely using computers for their concerns.

Insurance companies are maintaining a database of all clients with information showing −

  • Procedure to continue with policies
  • Starting date of the policies
  • Next due installment of a policy
  • Maturity date
  • Interests due
  • Survival benefits
  • Bonus


The computer helps in providing a lot of facilities in the education system.

  • The computer provides a tool in the education system known as CBE (Computer Based Education).
  • CBE involves control, delivery, and evaluation of learning.
  • Computer education is rapidly increasing the graph of number of computer students.
  • There are a number of methods in which educational institutions can use a computer to educate the students.
  • It is used to prepare a database about performance of a student and analysis is carried out on this basis.


In marketing, uses of the computer are following:

  • Advertising: With computers, advertising professionals create art and graphics, write and revise copy, and print and disseminate ads with the goal of selling more products.
  • Home Shopping: Home shopping has been made possible through the use of computerized catalogues that provide access to product information and permit direct entry of orders to be filled by the customers.


Computers have become an important part in hospitals, labs, and dispensaries. They are being used in hospitals to keep the record of patients and medicines. It is also used in scanning and diagnosing different diseases. ECG, EEG, ultrasounds and CT scans, etc. are also done by computerized machines.

Following are some major fields of health care in which computers are used.

  • Diagnostic System: Computers are used to collect data and identify the cause of illness.
  • Lab-diagnostic System: All tests can be done and the reports are prepared by computer.
  • Patient Monitoring System: These are used to check the patient’s signs for abnormality such as in Cardiac Arrest, ECG, etc.
  • Pharma Information System: Computer is used to check drug labels, expiry dates, harmful side effects, etc.
  • Surgery: Nowadays, computers are also used in performing surgery.

Engineering Design

Computers are widely used for Engineering purpose.

One of the major areas is CAD (Computer Aided Design) that provides creation and modification of images. Some of the fields are:

  • Structural Engineering: Requires stress and strain analysis for design of ships, buildings, budgets, airplanes, etc.
  • Industrial Engineering: Computers deal with design, implementation, and improvement of integrated systems of people, materials, and equipment.
  • Architectural Engineering: Computers help in planning towns, designing buildings, determining a range of buildings on a site using both 2D and 3D drawings.


Computers are largely used in defence. Modern tanks, missiles, weapons, etc. Military also employs computerized control systems. Some military areas where a computer has been used are:

  • Missile Control
  • Military Communication
  • Military Operation and Planning
  • Smart Weapons


Communication is a way to convey a message, an idea, a picture, or speech that is received and understood clearly and correctly by the person for whom it is meant. Some main areas in this category are:

  • E-mail
  • Chatting
  • Usenet
  • FTP
  • Telnet
  • Video-conferencing


Computers play an important role in government services. Some major fields in this category are:

  • Budgets
  • Sales tax department
  • Income tax department
  • Computation of male/female ratio
  • Computerization of voters lists
  • Computerization of PAN card
  • Weather forecasting

Computers can be broadly classified by their speed and computing power.

Type Specifications
1 PC (Personal Computer) It is a single user computer system having moderately powerful microprocessor
2 Workstation It is also a single user computer system, similar to personal computer however has a more powerful microprocessor.
3 Mini Computer It is a multi-user computer system, capable of supporting hundreds of users simultaneously.
4 Main Frame It is a multi-user computer system, capable of supporting hundreds of users simultaneously. Software technology is different from minicomputer.
5 Supercomputer It is an extremely fast computer, which can execute hundreds of millions of instructions per second.

Generation in computer terminology is a change in technology a computer is/was being used. Initially, the generation term was used to distinguish between varying hardware technologies. Nowadays, generation includes both hardware and software, which together make up an entire computer system.

There are five computer generations known till date. Each generation has been discussed in detail along with their time period and characteristics. In the following table, approximate dates against each generation has been mentioned, which are normally accepted.

Following are the main five generations of computers.

Generation & Description
1 First Generation

The period of first generation: 1946-1959. Vacuum tube based

2 Second Generation

The period of second generation: 1959-1965. Transistor based

3 Third Generation

The period of third generation: 1965-1971. Integrated Circuit based

4 Fourth Generation

The period of fourth generation: 1971-1980. VLSI microprocessor based

5 Fifth Generation

The period of fifth generation: 1980-onwards. ULSI microprocessor based

A computer is an electronic device that manipulates information or data. It has the ability to store, retrieve, and process data.
Nowadays, a computer can be used to type documents, send email, play games, and browse the Web. It can also be used to edit or create spreadsheets, presentations, and even videos. But the evolution of this complex system started around 1940 with the first Generation of Computer and evolving ever since.

There are five generations of computers.

  1. First Generation
    • Introduction:
      1. 1946-1959 is the period of first generation computer.
      2. P.Eckert and J.W.Mauchy invented the first successful electronic computer called ENIAC, ENIAC stands for “Electronic Numeric Integrated And Calculator”.
    • Few Examples are:
      1. ENIAC
      2. EDVAC
      3. UNIVAC
      4. IBM-701
      5. IBM-650
    • Advantages:
      1. It made use of vacuum tubes which are the only electronic component available during those days.
      2. These computers could calculate in milliseconds.
    • Disadvantages:
      1. These were very big in size, weight was about 30 tones.
      2. These computers were based on vacuum tubes.
      3. These computers were very costly.
      4. It could store only a small amount of information due to the presence of magnetic drums.
      5. As the invention of first generation computers involves vacuum tubes, so another disadvantage of these computers was, vacuum tubes require a large cooling system.
      6. Very less work efficiency.
      7. Limited programming capabilities and punch cards were used to take inputs.
      8. Large amount of energy consumption.
      9. Not reliable and constant maintenance is required.
  1. Second Generation
    • Introduction:
      1. 1959-1965 is the period of second-generation computer.
      2. Second generation computers were based on Transistor instead of vacuum tubes.
    • Few Examples are:
      1. Honeywell 400
      2. IBM 7094
      3. CDC 1604
      4. CDC 3600
      5. UNIVAC 1108
    • Advantages:
      1. Due to the presence of transistors instead of vacuum tubes, the size of electron component decreased. This resulted in reducing the size of a computer as compared to first generation computers.
      2. Less energy and not produce as much heat as the first genration.
      3. Assembly language and punch cards were used for input.
      4. Low cost than first generation computers.
      5. Better speed, calculate data in microseconds.
      6. Better portability as compared to first generation
    • Disadvantages:
      1. A cooling system was required.
      2. Constant maintenance was required.
      3. Only used for specific purposes.
  1. Third Generation
    • Introduction:
      1. 1965-1971 is the period of third generation computer.
      2. These computers were based on Integrated circuits.
      3. IC was invented by Robert Noyce and Jack Kilby In 1958-1959.
      4. IC was a single component containing number of transistors.
    • Few Examples are:
      1. PDP-8
      2. PDP-11
      3. ICL 2900
      4. IBM 360
      5. IBM 370
    • Advantages:
      1. These computers were cheaper as compared to second-generation computers.
      2. They were fast and reliable.
      3. Use of IC in the computer provides the small size of the computer.
      4. IC not only reduce the size of the computer but it also improves the performance of the computer as compared to previous computers.
      5. This generation of computers has big storage capacity.
      6. Instead of punch cards, mouse and keyboard are used for input.
      7. They used an operating system for better resource management and used the concept of time-sharing and multiple programming.
      8. These computers reduce the computational time from microseconds to nanoseconds.
    • Disadvantages:
      1. IC chips are difficult to maintain.
      2. The highly sophisticated technology required for the manufacturing of IC chips.
      3. Air conditioning is required.
  1. Fourth Generation
    • Introduction:
      1. 1971-1980 is the period of fourth generation computer.
      2. This technology is based on Microprocessor.
      3. A microprocessor is used in a computer for any logical and arithmetic function to be performed in any program.
      4. Graphics User Interface (GUI) technology was exploited to offer more comfort to users.
    • Few Examples are:
      1. IBM 4341
      2. DEC 10
      3. STAR 1000
      4. PUP 11
    • Advantages:
      1. Fastest in computation and size get reduced as compared to the previous generation of computer.
      2. Heat generated is negligible.
      3. Small in size as compared to previous generation computers.
      4. Less maintenance is required.
      5. All types of high-level language can be used in this type of computers.
    • Disadvantages:
      1. The Microprocessor design and fabrication are very complex.
      2. Air conditioning is required in many cases due to the presence of ICs.
      3. Advance technology is required to make the ICs.
  1. Fifth Generation
    • Introduction:
      1. The period of the fifth generation in 1980-onwards.
      2. This generation is based on artificial intelligence.
      3. The aim of the fifth generation is to make a device which could respond to natural language input and are capable of learning and self-organization.
      4. This generation is based on ULSI(Ultra Large Scale Integration) technology resulting in the production of microprocessor chips having ten million electronic component.
    • Few Examples are:
      1. Desktop
      2. Laptop
      3. NoteBook
      4. UltraBook
      5. Chromebook
    • Advantages:
      1. It is more reliable and works faster.
      2. It is available in different sizes and unique features.
      3. It provides computers with more user-friendly interfaces with multimedia features.
    • Disadvantages:
      1. They need very low-level languages.
      2. They may make the human brains dull and doomed.