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Introduction to Computers: History, Characteristics, and Generations

This article provides an introduction to computers, including their history, basic functions, and characteristics such as speed, accuracy, diligence, versatility, reliability, and storage. It also discusses the different generations of computers, from vacuum tube-based machines to the transistor era.

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Introduction to Computers: History, Characteristics, and Generations

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  1. UNIT-I Introduction To Computers

  2. Introduction to Computer • Early days people use fingers for computing purpose. • As years go, the computing needs also grew. This leads to the invention of calculators and computers. • The term computer is derived from the word compute, it means to calculate.

  3. Definition • Computer is an electronic device. It accepts data, process the data and gives the desired output. COMPUTER INPUT OUTPUT

  4. Basic functions or operations • Input • Processing • Output • Storing • Controlling

  5. Basic operations (Cont) • Input It is the process of getting the data from the user or from somewhere else into the computer to process. • Processing It is the process of converting the input to output.

  6. Basic operations (Cont) • Output It is the outcome or result of the process. • Storing It is the process of saving the data. so that it can be retrieved whenever needed.

  7. Basic operations (Cont) • Controlling It is the process of directing the sequence in which the operations to be performed.

  8. Applications of computer: • Business • Industry • Home • Education • Printing & publishing • Entertainment etc.,

  9. CHARACTERISTICS OF COMPUTER

  10. CHARACTERISTICS OF COMPUTER • Speed • Accuracy • Diligence • Versatility • Reliability • Storage

  11. CHARACTERISTICS OF COMPUTER (cont) • Speed The computer process the data extremely fast. (i.e.) in millions (1,000,000) of instructions and even more per second. A computer can perform a huge task in few sec where a human being may take hours or even days to complete the same task.

  12. CHARACTERISTICS OF COMPUTER (cont) • Accuracy The degree of accuracy of computer is very high and every calculation is performed with the same accuracy. The accuracy level is determined on the basis of design of computer. The errors in computer are due to human and inaccurate data.

  13. CHARACTERISTICS OF COMPUTER (cont) • Diligence A computer is free from tiredness, lack of concentration etc. It can work for hours without creating any error. If millions of calculations are to be performed, a computer will perform every calculation with the same accuracy. Due to this capability it overpowers human being in routine type of work.

  14. CHARACTERISTICS OF COMPUTER (cont) • Versatility It means the capacity to perform completely different type of work. For example At a moment a computer can be used to draft a letter. Next moment it can be used print a document or play a music file etc.,

  15. CHARACTERISTICS OF COMPUTER (cont) • Reliability It produces results without any error. Only human made errors can occur So they are trustworthy machines.

  16. CHARACTERISTICS OF COMPUTER (cont) • Storage Computers are capable of storing huge amount of data and it can be located and retrieved very quickly. It uses storage devices such as hard disk to store huge amount of data.

  17. Generations of Computers

  18. Generations of Computers (Cont) First Generation Computers(1940-1956): • These computers were vacuum tube based machines. • They used magnetic drums for memory. • Input were fed into the computer using Punched cards • The size of these computers were very large and it produce more heat. • They lacked in versatility and speed. • They were more expensive.

  19. First Generation Computers(1940-1956): • Speed: Fastest computing device of its time • Technology: Vacuum Tubes : • Made up of glass contains filaments, when heated generates electrons which helps in amplification and de amplification of signals • I/p & O/p : Punched card and print out • Programming language: Machine level language • Example: • EDSAC: Electronic delay storage automatic calculator • EDVAC: Electronic discrete variable automatic computer

  20. First Generation Computers(1940-1956): • Advantages: • Fastest computing device of their time • Execute complex mathematical problems in an efficient manner • Disadvantages: • Large & Bulky • Difficult to program • Cannot be transferred from one place to another • These are special purpose computers • Generates huge amount of heat and hence prone to hardware faults

  21. Generations of Computers (Cont) Second Generation Computers (1956-1963) • Here the Transistorreplaced the bulky vacuum tubes. • Transistors are smaller than vacuum tubes and have higher operating speed. • Thus the size of the computer got reduced considerably. • Manufacturing cost was also very low.

  22. Second Generation Computers (1956-1963): • Speed: Faster than first generation • Technology: Transistor : • Used to increase the power of incoming signals. • It has 3 connections: • Base : Through which incoming signals are sent • Collector : Collects amplified signal • Emitter : Emits amplified signal • I/p & O/p : Punched card and print out • Programming language: Assembly language • Example: • IBM 1401 • IBM 1620

  23. Second Generation Computers (1956-1963): • Advantages: • Fastest computing device of their time • Easy to program • Light weight • Low power consumption • Low maintenance • Transferred from one place to another easily • Disadvantages: • High cost • Limited to special purpose tasks • Generates considerable amount of heat

  24. Generations of Computers (Cont) Third Generation Computers (1964-1975) • These computers were based on Integrated Circuits(ICs) Technology. • A single IC has many transistors, registers and capacitors built on a single thin slice of silicon. • So that the size of the computer got further reduced. • These Computers were small in size, low cost, large memory and processing speed is very high.

  25. Third Generation Computers (1964-1975): • Speed: Fastest computing device of its time • Technology: Integrated Circuits : Also known as micro electronics technology • Programming language: High level language • Example: • IBM 360 • Honeywell 6000

  26. Third Generation Computers (1964-1975): • Advantages: • Computational time was measured in nano seconds • Requires low power to operate • Small size • Installation is very easy • Able to execute any type of applications • More reliable & requires less maintenance • Easily transportable • Disadvantages: • Storage capacity was very small • Performance will get degrade while executing large applications • Cost is very high • Required to be placed in air conditioned plates

  27. Generations of Computers (Cont) Fourth Generation Computers(1975-1989) • It uses very large scale Integrated Circuits (VLSI) built on a single silicon chip called microprocessors . • These computers are called microcomputers. • Thus the size of the computer got reduced. • The personal computer (PC) are comes under the Fourth Generation.

  28. Fourth Generation Computers (1975-1989): • Speed: Fastest computing device of its time • Technology: VLSI : Very large scale Integration • It leads to the development of GUI, Operating Systems, Various storage devices, I/O devices and LAN • It has 3 components: • Microprocessors • Memory • I/O Controls • Programming language: High level language • Example: • IBM PC series • Apple Series

  29. Fourth Generation Computers (1975-1989): • Advantages: • Very powerful in terms of speed & time • Storage capacity is very high & it is very fast • Highly reliable and requires low maintenance • Provides user friendly environment using GUI(Graphical user interface) • Programs are highly portable • Highly versatile and requires less power • Disadvantages: • The soldering of VLSI chips on the wiring board was not an easy task • Working of these computers depends on instructions given by the programmer

  30. Generations of Computers (Cont) Fifth Generation Computer(1989-Till date) • The speed is extremely high in fifth generation computer. • The concept of Artificial intelligence has been introduced to allow the computer to take its own decision. • It is still in a developmental stage .

  31. Fifth Generation Computers (1989-Till date): • Speed: Faster of all times • Technology: ULSI : Ultra large scale Integration • It has more than10 million electronic components • It increases the power & speed of the microprocessor • Programming language: • High level language • Integrated development environment • Example: • Laptop • PDA

  32. Fifth Generation Computers (1989-Till date) • Advantages: • Fastest & powerful computers till date • Able to execute a large no of application at very high speed. • ULSI Technology helps in decreasing the size of computers. • Multimedia features are available • Resource sharing is possible & is highly versatile • Disadvantages: • Lack of human like Intelligence

  33. Classification of Computer

  34. Classification of Computer Computer Based on Operating Principles Based on Applications Based on Size & Capabilities • Analog Computers • Digital Computers • Hybrid Computers • Micro Computers • Mini Computers • Mainframe Computers • Super Computers • Special Purpose Computers • General Purpose Computers

  35. Classification of Computer (Cont) Microcomputer • Microcomputer is at the lowest end of the computer range in terms of speed and storage capacity. Eg: Desktop, Laptop, Tablet PC, Smart Phones.

  36. Classification of Computer (Cont) Mini Computer • This is designed to support more than one user at a time. (up to 200 users) • It possesses large storage capacity and operates at a higher speed. • This type of computer is generally used for processing large volume of data in an organisation. • Eg:Servers in Local Area Networks (LAN).

  37. Classification of Computer (Cont) Mainframes • They operate at very high speed, having very large storage capacity and can handle the work load of many users(more than 200 users. • They are generally used in centralised databases.

  38. Classification of Computer (Cont) Supercomputer • They are the fastest and most expensive machines. • They have high processing speed compared to other computers. • They have also multiprocessing technique. • Supercomputers are mainly being used for whether forecasting, biomedical research, and other areas of science and technology

  39. BASIC ORGANISATION OF COMPUTER

  40. Basic organisation of computer I/P UNIT MEMORY UNIT O/P UNIT CACHE MEMORY Block Diagram of a Computer System REGISTERS ALU CONTROL UNIT

  41. Basic organisation of computer • INPUT • The input unit is used to feed information or instruction to the computer. • Input Devices: • Keyboard • Mouse • Scanner…

  42. Basic organisation of computer (cont) • MEMORY UNIT • Used to store • Data • Instructions • Intermediate Results & • Final Processed Results • Types • Primary • Secondary • Internal Processor memory • Primary memory is used to store temporary data. • Ex:RAM, ROM etc,. • Secondary memory is used to store information permanently • Ex:Hard disk. • Internal Processor memory is used to store temporary processor data • Ex:CPU Registers

  43. Basic organisation of computer (cont) • CENTRAL PROCESSING UNIT (CPU) • Responsible for processing the data & instruction and controlling all other components • Operation (4 Phases) • Fetching Instruction from the memory • Decoding the instruction • Executing the instructions • Storing the results in to the memory • It contains the following components • CONTROL UNIT • ALU • MEMORY

  44. Basic organisation of computer (cont) • CONTROL UNIT • It controls all other units in the computer. • It directs the sequence in which operations to be performed. • It also controls the flow of data between various units.

  45. Basic organisation of computer (cont) • ARITHMETIC & LOGICAL UNIT • It performs all arithmetic & logical operations. • i.e. arithmetic operations like addition, subtraction, multiplication, division etc,. And logical operations like AND,OR,NOT etc,.

  46. Basic organisation of computer (cont) • Registers • CPU contains a few special purpose, temporary storage units called registers • They are high speed memory locations • Used for handling instructions, data & intermediate results that are currently being processed • Registers • Program Counter(PC) • Instruction Register(IR) • Memory Address Register(MAR) • Accumulator

  47. Basic organisation of computer • OUTPUT • The output unit is used to display the result of the process. • Data processed by CPU is made available to the end user by O/P devices • Commonly used O/P devices: • Monitor • Printer • Speaker

  48. Components of Computers

  49. Components of Computers • Hardware The physical components present in the computer. • Software It is a collection of programs and it can perform some operaions.

  50. Components Present inside the cabinet • Motherboard • Processor • SMPS • Disk drives • RAM & ROM etc,.

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