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In this lesson you will learn:

Savani and Ali have brought things like abacus, some pictures of old computers, a slide rule that was made by hand, a cloth with nice designs, some notes written on sheets of paper. Others are looking on and wondering, how these articles are related to history of computers. Ali has in his hand a banner which says “People were the first computers”.Savani: We have gathered history of computers right from 3rd century B. C. It is very interesting to find what they did when there were no computers. Moz: We have been using the computers for the past 40 years. But the origin of the concepts, algorithms and the developments of computations, date back to the very early cultures.Ali: In very early days that are in B. C when there were no computational devices, they used pebbles, bones and the fingers of hands which were called counters, to count and calculate. Savani: They even used ropes for some measurements and shapes for example: 3-4-5 right triangle was a device for assuring a right angle, using ropes with 12 evenly spaced knots.

Ali: Many such algorithms were developed around the world by early mathematician like Panini, Euclid, Leibniz and others. Savani: Yes. And by the middle of 16th century explorations of various continents and trading brought in the requirements of precise calculations of sea routes, accounting, etc. Savani: In 16th century some mechanical devices were developed to assist in tedious and repetitive calculations like generating calendars of a year, taxing, trading. Ali: I am sure they must have needed a lot of calculations, to build pyramids, Taj Mahal, to weave the designs for the beautiful old tapestry that we see in many places, and when they wanted to travel from one place to another.

Savani: We found this example of how they found prime numbers in third century B. C.

Use of counters for Calculations in third – sixth century B.C

4. History of computers and applications

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Moz: Good observations. So they started inventing devices for precise calculations and automation of certain tasks.Ali: The first computers were people. This was a job title given to people who did repetitive calculations for navigational tables, planetary positions and other such requirements. Savani: Mostly women with mathematical proficiency were employed for the job. Moz: So you have also gathered information about the inventions, the innovative ideas and the algorithms of the earlier days which are in some form or the other used in building the first to third generation of computers. Savani: Yes. We have listed a few examples in the following:

The Slide rule which was even used for landing man on moon. This was used by NASA engineers in 1960s for Apollo mission.

Napier bones-Numbers 0 to 9 were marked on a set of ivory sticks in such a way that the product of any number can be found by placing the sticks side by side.

Pascaline built by Pascal for hisfather who was a tax collector.

Stepped reckoner byLeibniz using flutes.

Schikard’s calculatingclock with gears

Simple devices to aid human calculators – 16th century

Devices with gears and flutes for calculations – 16 -17th century

http://www.inmagine.com/searchterms/abacus.htmlhttp://mathworld.wolfram.com/images/eps-gif/NapiersBones_1000.gifhttp://www.fotosearch.com/photos-images/slide-rule.html

http://en.wikipedia.org/wiki/File:Arts_et_Metiers_Pascaline_dsc03869.jpghttp://en.wikipedia.org/wiki/Stepped_Reckoner

Automation with punched cards 18-19th century http://en.wikipedia.org/wiki/Jacquard_loom

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Savani: The Jacquard loom invented by Joseph Marie Jacquard used punched cards to control a sequence of operations. A pattern of the loom’s weave could be changed by changing the punched card. Moz: Why do you think jacquard looms are important?Ali: In Scratch programming, the computer takes the blocks one by one and executes them. The loom too weaves line by line in a sequence the design on the punched card.Savani: In computers we use some input device like keyboard to input data. The punched card is like an input to the loom. Moz: Yes. You are right. Babbage later used the punched card idea, to store data in his analytical machine.

Ali: Boolean algebra which is extensively used in computers was also developed in 19th century by the mathematician George Boole. Moz: Yes. This is one of the most important concepts in computers. You will be learning about these constructs of programming soon. Note that the 19th century contributions of automating and the development of algorithm are of immense value to the development of electronic computers in the next century.

Ali: Early 20th century saw many analog computers which were mechanical or electrical or electro mechanical devices. Savani: What are analog computers?Moz: Let us understand by an example. You must have seen two types of clocks. Savani: Yes. I have seen. One which shows time with the the hour hand and the minute hand and the other which displays the time.Moz: The clock where information is represented by the hands of the clock is called an analog clock. Similarly in analog computers the numerical data is represented by mechanical or electrical variables.

Babbage – The Analytical MachineThe analytical machine was designed but not built. The main parts of his machine were called the “store” and “mill”. Punched card store data, which is equivalent to the memory unit in computers, Mill weaves or processes the data to give a result, which is equivalent to the central processing unit in computers. He used conditional processing of data. Example: if block in scratch.

ADA lovelace – First programmer Ada lovelace – First programmer.A friend of Babbage wrote the first sequence of instructions for various tasks for the analytical engine. Used programming concept of looping for repetitive actions. Example: repeat block in scratch. Used subroutines. A programming language with the name

Hollerith desk: Was used for U.S census.Consisted of a card reader which sensed the holes in the cards, a gear driven mechanism which could count (using Pascal’s mechanism which we still see in car odometers), and a large wall of dial indicators. (a car speedometer is a dial indicator) to display the results of the count.

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Mechanical computation machines - 19th century

First half of 20th century

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Moz: In the first half of 20th century many mechanical and electrical computers were designed and built. These were for limited purpose like solving some mathematical equations, decoding messages, for tables of firing artillery in world war II.Moz: Yes. These computers were based on binary representation of data and boolean algebra. Gurpreet: We have gathered information about the binary representation.Moz: We can discuss about this important concept in the next lesson.

A computer in which numerical data are represented by measurable • physical variables, such as electrical voltage.A computer that represents information by variable quantities • (Example: positions or voltages)Is a mechanical, electrical, or electronic computer that performs • arithmetical operations by using some variable physical quantity, such as mechanical movement or voltage, to represent numbersAn analog computer is a form of computer that uses the continuously-• changeable aspects of physical phenomena such as electrical,[1] mechanical, or hydraulic quantities to model the problem being solved. In contrast, digital computers represent varying quantities incrementally, as their numerical values change.A computer is which quantities are represented by physical variables; • problem parameters are translated into equivalent mechanical or electrical circuits as an analog for the physical phenomenon being investigated.A computer or computational device in which the problem variables • are represented as continuous, varying physical quantities. An analog computer implements a model of the system being studied. The physical form of the analog may be functionally similar to that of the system, but more often the analogy is based solely upon the mathematical equivalence of the interdependence of the computer variables and the variables in the physical system.

AnalogC

once

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1936- Alan Turing regarded to be the father of modern Computer Science provided a formalisation for the concept of algorithm and computations.

1941- Konrad Zuse inventor of the program-controlled computer, built the first working computer. This computer was based on magnetic storage.Atanasoff-Berry computer which used vacuum tube, binary numbers, was non programmable.

1943- Colossus a secret British computer with limited programmability built using vaccum tubes, was built to break the German wartime codes. It was the first computer to read and decipher the codes using cryptography.

1944- Harvard Mark I an electromechanical computer built out of switches, relays, rotating shafts, and clutches had limited programmability. It used punched paper tape instead of the punched cards. It worked for almost 15 years.

Grace Hopper was the primary programmer. She invented the first high level language called Flow-Matic which later developed into COBOL. She also constructed the first compiler. She found the first computer “bug”: a dead moth that got into the Mark I and whose wings were blocking the reading of the holes in the paper tape. The word “bug” had been used to describe a defect since at least 1889 but Hopper is credited with coining the word “debugging” to describe the work to eliminate program faults.

1946 – ENIAC used decimal arithmetic and is called the first general purpose electronic computer. It required rewiring to change the programming. John Mauchly and the J. Presper Eckert got funding from the war department after promising they could build a machine that would replace all the “computers”, meaning the women who were employed calculating the firing tables for the army’s artillery guns. The day that Mauchly and Eckert saw the first small piece of ENIAC work, the persons they ran to bring to their lab to show off their progress were some of these female computers (one of whom remarked, “I was astounded that it took all this equipment to multiply 5 by 1000”).

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Mechanical computation machines - 19th century

Savani: Next there was something called the “Stored program architecture” of Von Neumann in 1945. With this architecture rewiring was not required to change a program. Moz: Yes. The program and data was stored in memory and instructions were processed one after the other. Ali: The input was typed on a terminal which looks like a monitor with keyboard in the front or on cards. Each instruction was typed on one card and the deck of cards was read by a card reader and stored in memory. Moz: Yes. And those who submitted the program had to wait till their program was processed and output printed and given to them.Savani: If they had to change the program they must have typed another card and inserted in the deck of cards.

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EDVAC - Eckert and Mauchly’s teamed up with the mathematician John von Neumann to design EDVAC, which pioneered the stored program.

UNIVAC - first commercial computer sold to the Census bureau, the first computer to employ magnetic tape.

Mainframe computers- had timesharing, that is 100 users could use the computer at a time. They used a teletype to type the instruction. Alternatively one could type their instructions on cards on a key punch machine and submit a deck of cards which used to be processed in batch mode. This meant that one could submit the program and come back later to collect the output.

FORTRAN- FORmula TRANslation, developed in the mid-1950s, for use in scientific and numerical computing applications.

COBOL- Common Or Business Oriented Language, designed at the end of the 1950s by Admiral Grace Hopper, programs attempt to mimic natural language descriptions, mostly used for business applications.

LISP- List Processing, was developed by John McCarthy and a team of research students at M.I.T. In 1960, widely used in academic environments as a language for programming Artificial Intelligence systems.

ALGOL60 was designed by an international committee working between 1958 and 1963, a general-purpose language, with a particular emphasis on scientific and numerical applications.

Teletype Key punch machine

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Electronic digital computers - mid twentieth century onwards

High level languages

Moz: Yes. So technology advanced as the requirements of increased speed, precision, immediate results, increased and the problems encountered during the operation of the computer.

Ali: Some of the early programming languages that were developed are Fortran, Cobol, Lisp, Algol etc. We have collected some important info about these programming languages.

Savani: The present computer has crossed 5 generations from 1945 to this date. Ali: In the beginning the computers were huge like the Eniac, Edvac, later on the size started decreasing and the speed started increasing.Savani: The storage space also started increasing.Ali: Most importantly the reliability of computers increased and the cost also started decreasing.Moz: Yes. Invention of microprocessors revolutionised the computer development and due to the reduction of cost, by 1990 students could own a personal computer.Savani: We have given already details of the first generation computers which were the beginning of the current day computers. A summary of the five generations of computers is listed below.

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The classification of generations has been done based on technology, speed, storage, reliability and cost.The first generation computers were named ‘Eniac’, ‘Edvac’, and ‘Univac’. These computers were made of vaccum tubes way back in 1945-55. They were huge in size and very costly to maintain.The second generation computers developed after 1955 had transistors in the place of vaccum tubes. Transistors were more reliable, much cheaper and smaller. This generation had more computing power, were smaller in size, easier to maintain and were more affordable than the previous generation.The third generation of computers were developed in the 1960’s and used integrated circuits. The trasistors were miniaturised and kept on silicon chips called the semiconductors which drastically increased the speed and efficiency of computers.The fourth generation computers were developed in the 1970’s and used microprocessors or chips.The microprocessors were smaller than a postage stamp and had tremendous computing capabilities.The fifth generation computers were developed in 1980’s and used the concept of Artificial intelligence. The different types of fifth generation computers are Desktop, notebook or laptop, palmtop, server, Mainframe and Super Computer.

Desktop• computers are based on IC’s.Notebook• or laptop computer is same as desktop but can be carried aroundPalmtop• is a miniatured version of notebook with limited capabilitiesServer• is a powerful version of desktop capable of catering to various applications in a network environmentMainframe• is a powerful version of server and is capable of handling huge applications and data processing.Super computer• has multiprocessors to perform typical scientific applications that need trillions of information per second while processing.

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The five generations of computers

Savani: Computer is also being used in many devices like the phones, household machines like washing machines. Ali: These are very small computers which cannot be programmed but are meant to help in the operation of these devices. Moz: These are called embedded devices. Savani: We enjoyed reading about the history of computers and collecting important information for the presentation. Moz: History teaches you not only how things were made but also how you can innovate and invent. That brings us to the next topic for the presentation “What is inside the computer and How it works”. Let us discuss this tomorrow. Ali: I am interested in looking at the inside of a computer. Can we see it tomorrow?Moz: Yes. You can. Savani: Chin Chinaki...

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Bios

Wake up!

Os

Boot up !

I am ready!

At the end of the lesson, you will be able to:

Categorize a computer component • into hardware and software.Identify various parts inside the • computer and state their functions.

Lesson Outcome