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Introduction to Computer and Generations of Computer by Er. Kamlesh Tripathi
- 1. INTRODUCTION TO COMPUTER In the beginning of the civilisation, people used their fingers and pebbles for computing purpose. This gives a clue into the origin of early computing concepts. With the growth in civilisation, the computing need also grew. The need for a mechanism to perform lengthy calculations led to the invention of first calculator and then computers. Functionalities of a computer Any digital computer carries out five functions in gross terms: Takes data as input. Stores the data/instructions in its memory and use them when required. Processes the data and converts it into useful information. Generates the output Controls all the above four steps. Definition The term ‘Computer’ is derived from the Latin word ‘compute’, which means to calculate. “A Computer is an electronic device that performs mathematical and non-mathematical operations with the help of instructions to process the information in order to achieve desired results through output devices like monitor or printer. ” In Other Words, Computer is an electronic data processing device which Acceptsand stores data input, Processes the data input, and Generatesthe output in a required format. Advantages Following list demonstrates the advantages of computers in today's arena. 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 picoseconds or MHz, GHz. It can perform millions of calculations in a few seconds as compared to man who will spend many months for doing the same task. INPUT OutputProcess Storage
- 2. Accuracy 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 correct input has been given. The O/P is totally dependent on the given instructions and input data. If the input given is incorrect, the result generated will also be incorrect. This concept is called ‘Garbage-In Garbage-Out (GIGO). Reliability A computer is a reliable machine. Modern electronic components have long lives. Computers are designed to make maintenance easy. 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 and many others. Versatility (Multitasking) 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. Diligence 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 do repeated work with same speed and accuracy. Disadvantages Following list demonstrates the disadvantages of computers in today's arena No I.Q A computer is a machine that has no intelligence to perform any task. Each instruction has to be given to computer. A computer cannot take any decision on its own. Dependency It functions as per a user’s instruction, so it is fully dependent on human being Environment The operating environment of computer should be dust free and suitable. No Feeling Computers have no feelings or emotions. It cannot make judgement based on feeling, taste, experience, and knowledge unlike a human being.
- 3. COMPUTER – COMPONENTS All types of computers follow a same basic logical structure and perform the following five basic operations for converting raw input data into information useful to their users.. Operation Description 1 Take Input The process of entering data and instructions into the computer system 2 Store Data Saving data and instructions so that they are available for processing as and when required. 3 Processing Data Performing arithmetic, and logical operations on data in order to convert them into useful information. 4 Output Information The process of producing useful information or results for the user, such as a printed report or visual display. 5 Control the workflow Directs the manner and sequence in which all of the above operations are performed. Input Unit This unit contains devices with the help of which we enter data into computer. This unit makes link between user and computer. The input devices translate the information into the form understandable by computer. Memory Unit Input Unit Control Unit Output Unit Arithmetic & Logic Unit CPU
- 4. CPU (Central Processing Unit) CPU consists of the following features: CPU is considered as the brain of the computer. CPU performs all types of data processing operations. It stores data, intermediate results and instructions (program). It controls the operation of all parts of computer. CPU itself has following three components ALU (Arithmetic Logic Unit) Memory Unit Control Unit ALU (Arithmetic Logic Unit) This unit consists of two subsections namely Arithmetic section Logic Section Arithmetic Section Function of arithmetic section is to perform arithmetic operations like addition, subtraction, multiplication and division. All complex operations are done by making repetitive use of above operations. Logic Section Function of logic section is to perform logic operations such as comparing, selecting, matching and merging of data. Memory or Storage Unit This unit can store instructions, data and intermediate results. This unit supplies information to the other units of the computer when needed. It is also known as internal storage unit or main memory or primary storage or Random access memory (RAM). Its size affects speed, power and capability. Primary memory and secondary memory are two types of memories in the computer. Functions of memory unit are: It stores all the data and the instructions required for processing. It stores intermediate results of processing. It stores final results of processing before these results are released to an output device. All inputs and outputs are transmitted through main memory.
- 5. Control Unit This unit controls the operations of all parts of computer but does not carry out any actual data processing operations. Functions of this unit are: It is responsible for controlling the transfer of data and instructions among other units of a computer. It manages and coordinates all the units of the computer. It obtains the instructions from the memory, interprets them, and directs the operation of the computer. It communicates with Input/output devices for transfer of data or results from storage. It does not process or store data. Output Unit Output unit consists of devices with the help of which we get the information from computer. This unit is a link between computer and users. Output devices translate the computer's output into the form understandable by users.
- 6. COMPUTER GENERATIONS 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. But nowadays, generation includes both hardware and software, which together make up an entire computer system. There are totally five computer generations known till date. Each generation has been discussed in detail along with their time period and characteristics. Here approximate dates against each generations have been mentioned which are normally accepted. Following are the main five generations of computers S.N. Generation & Description 1 First Generation The period of first generation: 19401956. Vacuum tube based. 2 Second Generation The period of second generation: 19561963. Transistor based. Developed by William Shockly 3 Third Generation The period of third generation: 1964 Early 1970s. Integrated Circuit based. 4 Fourth Generation The period of fourth generation: 1970sTill Date. VLSI microprocessor based. 5 Fifth Generation The period of fifth generation: Present & Beyond. ULSI microprocessor based
- 7. FIRST GENERATION The period of first generation was 19401956. The computers of first generation used vacuum tubes as the basic components for memory and circuitry for CPU( central processing u nit). These tubes, like electric bulbs, produced a lot of heat and were prone to frequent fusing of the installations, therefore, were very expensive and could be afforded only by very large organisations. In this generation mainly batch processing operating system were used. Punched cards, paper tape, and magnetic tape were used as input and output devices. The computers in this generation used machine code as programming language. The main features of first generation are: Vacuum tube technology Unreliable Supported machine language only Very costly Generated lot of heat Slow input and output devices Huge size Need of A.C. No portable Consumed lot of electricity SECOND GENERATION The period of second generation was 19561963. In this generation transistors were used that were cheaper, consumed less power, more compact in size, more reliable and faster than the first generation machines made of vacuum tubes. In this generation, magnetic cores were used as primary memory and magnetic tape and magnetic disks as secondary storage devices. In this generation assembly language and high-level programming languages like FORTRAN, COBOL was used. The computers used batch processing and multiprogramming operating system. The main features of second generation are: Use of transistors Reliable in comparison to first generation computers Smaller size as compared to first generation computers Generated less heat as compared to first generation computers Consumed less electricity as compared to first generation computers Faster than first generation computers Still very costly A.C. needed Supported machine and assembly languages Some computers of this generation were: IBM 1620, IBM 7094, CDC 1604, CDC 3600, UNIVAC 1108 Some Computers of this generation were: ENIAC (Electronic Numerical Integrator and Calculator) EDVAC (Electronic Discrete Variable Automatic Computer) UNIVAC (Universal Automatic Computer) EDSAC (Electronic Delay Storage Automatic Calculator) IBM-701 IBM-650
- 8. THIRD GENERATION The period of third generation was 19641970. The computers of third generation used integrated circuits I C ′ s in place of transistors. A single IC has many transistors, resistors and capacitors along with the associated circuitry. The IC was invented by Jack Kilby. This development made computers smaller in size, reliable and efficient. In this generation remote processing, timesharing, multiprogramming operating system were used. High-level languages F ORT RAN − I I TOI V, C OBOL, P ASCALP L/1, BAS IC, ALGOL − 68etc. were used during this generation. The main features of third generation are: IC used More reliable in comparison to previous two generations Smaller size generated less heat Faster Lesser maintenance Still costly A.C needed Consumed lesser electricity Supported high-level language FFOOUURRTTHH GGEENNEERRAATTIIOONN The period of fourth generation was 1970 till date. The computers of fourth generation used Very Large Scale Integrated V LS I circuits. VLSI circuits having about 5000 transistors and other circuit elements and their associated circuits on a single chip made it possible to have microcomputers of fourth generation. Fourth generation computers became more powerful, compact, reliable, and affordable. As a result, it gave rise to personal computer P C revolution. In this generation time sharing, real time, networks, distributed operating system were used. All the high-level languages like C, C++, DBASE etc., were used in this generation. The main features of fourth generation are: VLSI technology used (Microprocessor) Very cheap Portable and reliable Use of PC's Very small size No A.C. needed Concept of internet was introduced Great developments in the fields of networks Computers became easily available Some Computers of this generation were: DEC 10 STAR 1000 PDP 11 CRAY-1 Super Computer CRAY-X-MP Super Computer Some computers of this generation were: IBM-360 series Honeywell-6000 series PDP Personal Data Processor IBM – 370/168 TDC-316
- 9. FIFTH GENERATION In the fifth generation, the VLSI technology became ULSI (Ultra Large Scale Integration) technology, resulting in the production of microprocessor chips having ten million electronic components. This generation is based on parallel processing hardware and AI (Artificial Intelligence) software. AI is an emerging branch in computer science, which interprets means and method of making computers think like human beings. All the high-level languages like C and C++, Java, .Net etc., are used in this generation. AI includes: Robotics Neural Networks Game Playing Development of expert systems to make decisions in real life situations. Natural language understanding and generation. The main features of fifth generation are: ULSI technology Development of true artificial intelligence Development of Natural language processing Advancement in Parallel Processing Advancement in Superconductor technology More user friendly interfaces with multimedia features Availability of very powerful and compact computers at cheaper rates Some computer types of this generation are: Desktop Laptop NoteBook UltraBook ChromeBook