# 8. History Of Computers: From Abacus To Smart-phones

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8. History of Computers: FromAbacus to Smart-phonesAim: In this lesson, you will learn:Various devices that have been used for computations in the past.Major milestones in development of modern day computersDevelopment of Internet, browser and other Internet based applications, games and Linux.Jyoti and Tejas have brought things like abacus,some pictures of old computers, a handmadeslide rule, a cloth with nice designs, somenotes written on sheets of paper. Others arelooking on and wondering, how these articlesare related to history of computers.Jyoti: We have gathered history of computersright from 3rd century B.C. It is very interestingto find, what they did when there were nocomputers.i. Information gatheringMoz: We have been using the computers forthe past 40 years. But the origin of the concepts, algorithms and the developments in computationsdate back to the very early cultures.Tejas: In very early days that is in B.C, when there were no computational devices, people usedpebbles, bones and the fingers of hands to count and calculate.Jyoti: They even used ropes and shapes for some measurements. For example: For assuring a rightangle, people used 3-4-5 right triangle shape or a rope with 12 evenly spaced knots, which couldbe formed into a 3-4-5 right triangle.Use of counters to aid calculations: 3rd - 6th century B.CRequirement of simple calculations were done in innovative ways with stones, pebbles and theyeven used bones. These were called counters. We can find many versions of the abacus now withmore complicated calculation abilities.Abacus – 6th century B. CCalculation using fingersSieve of Eratosthenes: Finding primenumbers in 3rd century B.CComputing Squares and sums by arranging counters90i. The first step for gathering information is to list what you know, what you do not know. Next, gather, consolidate, analyse and organisethe gathered information.

Tejas: Many such algorithms were developed around the world by early mathematicians like Panini,Euclid, Leibniz and others.Jyoti: Yes. By the middle of 16th century explorations of various continents and trading brought inthe requirements of precise calculations of sea routes, accounting, etc. Some mechanical deviceswere also developed to assist in tedious and repetitive calculations like generating calendars of ayear, taxing, trading.Tejas: The first computers were people. This was a job title given to people who did repetitivecalculations for navigational tables, planetary positions and other such requirements.Jyoti: Mostly women with mathematical proficiency were employed for the job.Simple devices to aid human calculations- 16th centuryExplorations of various continents and trading brought in the requirements of precise calculationsof sea routes, accounting, planetary positions, and navigational tables- 16th century.Napier bones- Numbers 0 to 9 were markedon a set of ivory sticks in such a way thatthe product of any number can be foundby placing the sticks side by side.The Slide rule was used for landing man onthe Moon. This was used by NASA engineersin 1960s for Apollo mission also.Devices with gears and flutes for calculations- 16th-17th centurySchikard’s calculatingclock with gearsPascaline built by Pascal for hisfather who was a tax collector.Stepped reckoner byLeibniz using flutes.Tejas: I am sure they must have needed a lot of calculations, to build pyramids and Taj Mahal,to weave the designs for the beautiful old tapesty that we see in many places and also when theywanted to travel from one place to another.Moz: Good observations. So they started inventing devices for precise calculations and automationof certain tasks. One of the important automation which is the Jaquard loom is important in thecomputer history.91

Automation with punched cards 18th-19th centuryTrade, travel, and increase in population (which demanded increase in requirements like clothing,food etc.), led to automation of machinery in 18th-19th century.Jyoti: The Jacquard loom invented by Joseph Marie Jacquard usedpunched cards to control a sequence of operations. A pattern ofthe loom’s weave could be changed by changing the punchedcard.Moz: Why do you think Jacquard looms are important?Tejas: In Scratch programming, the computer takes the blocksone by one and executes them. The loom too weaves line by linein a sequence the design on the punched card.Jyoti: In computers we use some input device like keyboard toinput data. The punched card is like an input to the loom.Moz: Yes. You are right. Babbage used the punched card idea, tostore data in his analytical machine.Tejas: Boolean algebra which is extensively used in computerswas also developed in 19th century by the mathematician GeorgeBoole.Moz: Yes. This is one of the most important concepts in computers. You will be learning aboutthese constructs of programming soon. Note that the 19th century contributions of automatingand the development of algorithm are of immense value to the development of electroniccomputers in the next century.Mechanical computation machines- 19th centuryDevelopments in logic and need for more complicated calculations led to mechanical computationdevices which were designed and implemented for varied degree of computations. But,accuracy, speed and precision could not be ensured due to the wear and tear of the mechanicalcomponents.Mechanical computation machines- Earlier 19th centuryInfoBabbage- The Analytical MachineThe anlaytical machine was designed but not built. The main parts of hismachine were called the “store” and “mill”. Punched card store data, whichis equivalent to the memory unit in computers. Mill weaves or processesthe data to give a result, which is equivalent to the central processing unitin computers. He used conditional processing of data. Example: If block inScratch.ADA lovelace- The first programmerADA lovelace, a friend of Babbage wrote the first sequence of instructionsfor various tasks for the analytical engine. Used programming concept oflooping for repetitive actions. Example: repeat block in Scratch. She usedsubroutines in her programs.Hollerith deskIt consisted of a card reader which sensed the holes in the cards, a gear driven mechanismwhich could count and a large wall of dial indicators to display the results of the count.For example: a car speedometer is a dial indicator. This was used for U.S census 1890.Tejas: Early 20th century saw many analog computers which were mechanical or electrical orelectro mechanical devices.92

These computers were built using vacuum tubes, transistors, integrated circuits which are classifiedinto the first three generations of computers. The classification of generations has been donebased on technology, speed, storage, reliability and cost.Computation machines- Second half of 19th centuryInfoFirst generation computersThese computers were named Eniac, Edvac, and Univac. These computers were made ofvaccum tubes way back in 1945-55. They were huge in size and very costly to maintain.Second generation computersThese computers developed after 1955, had transistors in the place of vaccum tubes.Trasistors were more reliable, much cheaper and smaller. This generation had morecomputing power, were smaller in size, easier to maintain and were more affordable thanthe previous generation.Third generation computersThese computers developed in the 1960’s, used integrated circuits. The trasistors wereminiaturised and kept on silicon chips called the semiconductors which drastically increasedthe speed and efficiency of computers.Jyoti: Microprocessor revolution brought in the explosion of usage of computers in every field.Tejas: The size of computers started decreasing and the speed started increasing.Jyoti: The storage space also started increasing.Tejas: Most importantly the reliability of computers increased and the cost started decreasing.Moz: Yes. Invention of microprocessors revolutionised the computer development and due to thereduction of cost, by 1990 students could own a personal computer.Computers with Microprocessors- 1970 onwardsUse of microprocessors in computers increased reliability, precision and reduced size and cost.This led to uses of computers in offices, colleges, personal use and exploration of computer usagein every field.Computation machines- After 1970’sInfoFourth generation computersThese were developed in the 1970’s and used microprocessors or chips. Themicroprocessors were smaller than a postage stamp and had tremendous computingcapabilities.Fifth generation computersThese were developed in 1980’s and used the concept of Artificial intelligence. Thedifferent types of fifth generation computers are Desktop, notebook or laptop, palmtop,server, Mainframe and Super Computer. 94Desktop computers are based on IC’s.Notebook or laptop computer is same as desktop but can be carried around.Palmtop is a miniature version of notebook with limited capabilities.Server is a powerful version of desktop capable of catering to various applications ina network environment.Mainframe is a powerful version of server and is capable of handling huge applicationsand data processing.Super computer has multiprocessors to perform typical scientific applications that needtrillions of information per second while processing.