INTRODUCTION ,FUNCTIONS,CHARACTERISTICS AND GENERATION OF COMPUTERS
What is a (Digital) Computer?
A computer is an electronic device system that accepts raw data as inputs, processes and manipulates them in digital form to give outputs (results) and store them for future use.
Functionality of a computer:
- Inputs from Input devices.
- Store or hold the input data.
- Process by CPU (Central Processing Unit).
- Output from Output devices.
- Store in memory.
Characteristics of Computer
- Speed
- Accuracy
- Diligence
- Versatility
- Storage and memorizing
- Automatic
- Processing
- Non-intelligent
Speed:
- A computer can do numbers of tasks with in a fraction of time for which a human takes a longer period of time even days or month.
- Capable of processing a very large amount of data.
- Speed in terms of microsecond, nanosecond and pico-second.
Accuracy:
- The result produced by a computer can be of higher precision and accuracy.
- Its accuracy can be increased higher as requirements.
- Provide outputs based on inputs.
Diligence (Carefulness):
- It is hard-working and keeps working until it is stopped.
- It keeps on working according to the program and do not feel tiredness or being lazy.
Versatility:
- Flexibility, changeability.
- Same computer can be used for different jobs or work.
- More usefulness.
- Same computer for different task.
Storage and Memorizing:
- A computer can store large amount of data.
- Once stored, it can be used any time as needed and don’t forget the data.
- Can store different types of data (Image, Text, audio etc).
Automatic:
- Once programmed, it automatically keeps doing the task.
Processing:
- Large amount of data and commands are processed in the computer.
- As requirement data are processed and gives an output.
- Every task need to be processed.
Non-intelligent:
- Absence of intellectualism.
- It can not decide what to do.
- It keeps working how it has been programmed to do.
- No logical thinking if not programmed.
Applications of Computer
- Education, Library and Design
- Industries and Manufacturing
- Research, Survey and Simulation
- Hospital and Health
- Data Processing
- Science and Engineering
- Offices and Hotel Management
- Advertisement and Marketing.
- Entertainment and Communication.
- Weather Forecasting
- Airlines and Navigation
Advantages of Computer
- Computers are much more accurate and reliable than any other devices and human beings.
- They are very much useful for repeated jobs which are difficult and tedious for humans to do.
- Computers are much faster than humans.
- With the help of computer, complicated things are easy to simulate and show.
- It is versatile and can perform various types of works.
- It can be used in multiple fields so it is called general purpose machine.
- Because of the availability of storage, data can be store for future use and programs can be modified to add features for different purpose.
- No repeated jobs so save time, labor and physical wastage (Draft) material.
- Communications technologies have advanced a lot with the use of computers.
Disadvantages Of Computer:
- It is expensive and is beyond the reach of poor people. This limitation is being overcome because its cost is drastically decreasing day by day.
- It is an electronic machine, so there is much danger of electric shock and other physical damage.
- Since people are getting more relied upon computer, sometimes the failure in devices and programs can produce unreliable information and cause loss of data in a great extent.
- It increases dependency on machine. Even for every simple calculation people need them.
- Although it helps in faster and cheaper communication, there is much danger for security leakage.
- It increases piracy of intellectual properties (movies, publications etc) in big volume.
- Since computers are used in sensitive areas like national defense, civil aviation, banking, even a simple fault can cause loss of life and property.
Generations of Computers
- First Generation (Vacuum tube based).
- Second Generation (Transistor based.)
- Third Generation (Integrated Circuit based.)
- Fourth Generation (VLSI microprocessor based.)
- Fifth Generation(Bio-Chips & Artificial Intelligence)
First Generation:
- The period of first generation was 1942-1954.
- Vacuum tubes (Valves) as basic components for memory and circuitry for CPU.
- Very large in size occupying entire room.
- Consume large amount of power (electricity) and produce large amount of heat.
- Punch cards and Paper tapes were used as Input and Outputs were limited on printouts.
- Use of machine level language.
- Storage capacity was limited to 1KB-4KB.
- Slow operating speeds and slowest than all of the other generations’ computers..
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| fig:First generation computer |
- Example: UNIVAC and ENIAC.
Second Generation:
- The period of second generation was 1952-1964.
- Transistors were used instead of vacuum tubes.
- Smaller in size as compared to First generation computers.
- Consumed less power and generate less heat compare to First generation computers.
- Faster and reliable than First generation computers.
- Assembly language and high level programming like FORTAN, COBOL were used.
- Use of magnetic core technology in place of magnetic drum.
- Magnetic core memories for internal storage, and magnetic disk and tapes for auxiliary memory.
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| fig:Second generation computer |
- Example: ATLAS , Mark III, IBM 7000
Note: A transistor is a small electronic device made up of semiconductor material like germanium and silicon. It is much smaller in size as compared to vacuum tubes and consumes less power. In 1947, Bell Laboratory introduces the first transistor and was used in computer in 1958.
Third Generation:
- The period of third generation was 1964-1972.
- Integrated Circuits (ICs) were used in place of transistors.
- Smaller in size than second generation as many transistors can be integrated in an IC.
- Low power consumption than previous generation.
- High level language like FORTAN-II, ALGOL-68 were used.
- More reliable and efficient than previous generation computers.
- Keyboard and monitor as input and output device.
- Real-time and multi-programming Operating system were used.
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| fig:Third generation computer |
- Example: IBM-360 series, IBM-370/168
Fourth Generation:
- The period of Fourth Generation was 1972-present.
- Use of Very Large Scale Integration (VLSI) technology and microprocessor.
- Since thousands of transistors and other circuits were integrated in a single chip, size of computer drastically decreased.
- Cheaper in price and lower power consumption.
- Major achievement in computer technology took place in this era including hardware and software.
- Still using the computer from this generation.
- Highly accurate, reliable & operation speed.
- Massive use of magnetic and optical storage device.
- Multiprocessing, Multiprogramming, multimedia and distributed computing possible.
- Concept of internet was introduced.
- Introduction of PC’s for general people.
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| fig:Fourth generation computer |
- Example : IBM PC, Pentium PC
Fifth Generation:
- The period of Fifth generation is present –future.
- Based on artificial intelligence and still in development.
- Some applications such as voice recognition are introduced.
- The use of parallel processing and superconductors.
- More user friendly interface with multimedia features.
- Quantum computation, molecular and nanotechnology uses that will change the face of computer.
- Development of devices to respond to natural language input.
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| fig:Fifth generation computer |
- Self learning and organization capability.
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