Module 1: Introduction to Computers & internet

1. Module 1: Introduction to Computers & internet • Historical Development of Computing • Development of the Internet

2. HISTORICAL DEVELOPMENT OF COMPUTING

3. Historical Development of Computing • The inventions before 1900AD were all crucial building blocks of the computing industry. • The Century began with a major milestone in the computing history, by the invention of the vacuum tube by John Ambrose Fleming. • This was a major development in computing as the vacuum tube played a major role in computing for the next half century. All digital computer in the first half century ran on vacuum / electronic tubes. • The next twenty years saw development of computing with a variety of inventions including the invention of the triode by Lee de Forest in 1906. • However, another major milestone invention, was to be born during this period. Although it was not to come into full use for some time, but 1926 saw the invention of the first semiconductor transistor that will come to dominate the computing industry in late years.

4. Historical Development of Computing…… • 1937 saw a milestone invention in the history of computing. The invention of the Turing Machine by Alan Turing in 1937 was as revolutionary as it was exciting. • Two years after Turing, in 1939, the world was to see its celebrated first digital computer developed by John Vincent Atanasoff, a lecturer at Iowa State College (now University). • Atanasoff’s computer was the first special –purpose electronic digital computer. • Around the same time Atanasoff and Berry were working on their model in 1939, Howard Aiken, a graduate of Harvard University, was developing the first large scale automatic digital computer. Aiken’s computer came to be known as the Harvard Mark I (also known as IBM automatic sequencer calculator- ASCC)

5. Historical Development of Computing…… • The next ten years saw the development of the actual working models of the digital computer as we know it today. • In 1943, Alan Turing, working as a cryptographer, constructed the COLOSSUS, considered by many as the world’s earliest working programmable electronic digital computer. The COLOSSUS, designed to break the German ENIGMA code, used about 1800 vacuum tubes and it was to execute a variety of routines. • Around the time the COLOSSUS was being developed by Alan Turing, a team of John William Mauchly and J. Presper Eckert Jr., working at the University of Pennsylvania, was developing anothervacuum tube-based general purpose electronic digital computer. • Their model named electronic numerical integrator and computer, (ENIAC) was 10 feet high, weighed 30 tons, occupied 1000 square feet, and used about 70,000 resistors, 10,000 capacitors, 6000 switches, and 18,000 vacuum tube.

6. Historical Development of Computing…… • After ENIAC went in use, the team encountered a number of problems the main being that it did not have an internal memory because it was hard-wired and it was consistently programmed by switches and diodes. This problem had to be worked on for the next model. • From 1944 through 1952, the team developed a new computer called the electronic discrete variable automatic computer – EDVAC. • This is believed to be the truly first general purpose digital computer. • EDVAC was a stored-program computer with internal read-write memory to store program instructions. • The stored program concept gave the device the capability for the program under execution to branch to alternative instruction sequences elsewhere in the stored program. • When it was completed in 1956, EDVAC was still a carousal machine with 4,000 vacuum tubes and 10,000 crystal diodes.

7. Historical Development of Computing…… • Although most of these activities were taking place in USA, there were other efforts in other countries. For example, around the time EDVAC was being developed, there was an experiment at the University of Manchester in the United Kingdom also based on the stored program concept. • Still in England, at Cambridge University, the electronic delay storage automatic calculator- EDSAC was produced in 1949. • Across the Atlantic in 1948, the universal automatic computer – UNIVAC I, became the first commercially available computer. • From that point, the general purpose computer took on a momentum of its own.

8. Historical Development of Computing…… • Companies built what came to be known as the mainframe, huge computers that consisted of a 4 to 5 feet by 8 feet tape drives, a huge control processing unit, a huge printer, several huge fixed disks, a large card reader and a paper punch. • These components usually filled a large room or two. Because these computers were big, expensive, and difficult to use – computers users could only use the computers through a computer operator. • The computer operator fed jobs to the computer via a card or tape reader. • Because of the fact that these computers were big, expensive and difficult to use, only large companies and institutions were able to use them.

9. Historical Development of Computing…… • Around mid to late sixties, a movement to make computers less expensive and more affordable started gathering momentum. • This movement led to a number of developments. First it led to the manufacture of a less expensive but smaller computer – the medium range computer commonly referred to as minicomputer. • Secondly, it started a mode of computing that later led to networking. This was the timesharing, where, one computer could be used by a number of users who would remotely connect on to the mainframe. • Third and most important, it led to a milestone in the history of computing. This milestone occurred between 1971 and 1976. This was the development of the first microprocessor. • A microprocessor is an integrated circuit with many transistors on a single board. Before the birth of the microprocessor, computer technology had developed to a point that vacuum tubes and diodes were no longer used.

10. The Development of the Microprocessor • The way forward was found by Ted Hoff. Hoff designed the world’s first microprocessor, the 4004. The fours in 4004, indicated that the device had a 4-bit data path. • The 4004 microprocessor was a four-chip system consisting of 256-byte ROM, a 32-bit RAM, 4-bit data path, and 10-bit shift register. It used 2,300 transistors to execute 60,000 operations per second, a top speed at the time . • The development of the first microprocessor caught the world off guard. Even Biscom, the company that had commissioned Hoff, did not understand the potential of the 4004. So they requested him to design the twelve-chip set they hard originally wanted him to design .

11. The Development of the Microprocessor …… • In 1972, Intel, designed and introduced the 8008, an 8-bit microprocessor based on the 4004. • The 8008 was historic in its own right in that it was the first microprocessor to use a compiler, a system program that interprets user inputs into machine code and machine code to system outputs understandable by the user. The 8008 supported the compiler called PL/M. Both the 4004 and the 8008 were specific application microprocessors. • The truly general purpose microprocessor come out in 1974. It was the 8080, an 8-bit device with 4,500 transistors and packing an astonishing 200,000 operations per second. • From 1974, the development of microprocessors exploded as companies like Motorala developed the 6800 in 1974, MOS Technology developed the 6502 in 1975, and Zilog developed the Z80 in 1976. Since then, many new companies have sprung up and the speed, density of transistors, and functionality of microprocessors has been on the rise.

12. Historical Development of Computer Software and Personal Computer (PC) • Up until mid 1970s, the development of computing science was led by hardware. Computers were designed and software was designed to fit the hardware. • The development of software to run the computers was in the hands of the companies that designed the hardware. • The break from this routine came from two fronts: 1976 when the Apple I and Apple II microcomputer were unveiled, and 1981 when IBM joined the PC wars. • These two developments started a new industry, the personal computing industry. • Perhaps the PC industry may not have been the way it is today, were it not the development of the personal computer operating system (OS).

13. Historical Development of Computer Software and Personal Computer (PC) ….. • The history of the development of the PC operating system, hence the birth of the PC industry, involved three players: IBM, Gary Kildall, the fellow who developed CP/M, the PC operating system many believe to be the first PC operating system, and Bill Gates, the develop of the Disk Operating System (DOS). • The story, part legend, behind these players is the story of the beginning of the PC. The legend has it that when IBM developed the personal computer based on Intel’s 8088 microprocessor, in 1981, IBM needed an operating system. It is alleged that IBM approached Both Kidall and Gates. However, Kidall was out flying and failed to attend to IBM’s request before Gates did. • Gates developed the first DOS and a version of the BASIC programming language for IBM and the rest is history

14. THE DEVELOPMENT OF THE INTERNET

15. The Development of the Internet • The Internet, a global network of computers, owes its development on the invention of four technologies: telegraph, telephone, radio, and computers. • History has it that the Internet originated from the early work of J.C.R. Licklider of Massachusetts Institute of Technology (MIT) on "Galactic Networks". • Licklider conceptualized a global interconnected set of computers with communication channels between them through which programs and data could be accessed quickly by any computer from any computer . • The networking concept envisioned by Licklider would support communication between network nodes using a concept of packetsinstead of circuits, thus enabling computers to talk to each other. • He left MIT to head the computer research program at the Department of Defense’s Defense Advanced Research Projects Agency (DARPA) in 1962.

16. The Development of the Internet…. • A year before, in 1961 at MIT, researcher Leonard Kleinrock had published what is believed to be the first published work on packet switching theory . • This work created the momentum for the packet switching network concept. • However, it was not the only work on the concept, there were two additional independent projects on this same topic, that of Donald Davies and Roger Scantleberg at the British National Laboratory (BNL) which later was credited with coining the term "packet", and that of Paul Baran at RAND.

17. The Development of the Internet…. • In 1965, Lawrence Roberts at MIT, who had been collaborating with Licklider, and Thomas M. Roberts connected and tested the TX-2 computer from Boston on the east coast of USA to the Q-32 computer in Los Angels on the west coast of the USA, with a low speed dial-up telephone line. • This test experiment created the first working Wide Area Network (WAN). This experiment opened up doors for all computer network communications as known today. • In 1966 Roberts left MIT for DARPA (Defense Advanced Research Projects Agency ) to develop the computer network concept publishing the first plan for ARPNET in 1967. • In 1968, a go ahead was given by DARPA for the development of the packet switches called Interface Message Processors (IMP).

18. The Development of the Internet…. • As the team, lead by Frank Heart and included Bob Kahn, developed the IMP, a team consisting of Roberts and Howard Frank designed the network topology and economics, and the network measurement system were done by Kleinrock and his team . • The work of these teams led to the testing of the first IMP at UCLA (University of California, Los Angeles ) in 1969 connected to a second node at Stanford Research Institute (SRI). • After these tests, more nodes were added to ARPNET and by end of 1969 four nodes formed ARPNET . From this point on the Internet started to grow. • However, more work was needed to incorporate the host-to-host protocol into ARPNET. The first host-to-host protocol called Network Control Protocol (NCP) was developed by the Network Working Group (NWG) in 1970. But NCP did not have “the ability to address networks further downstream than a destination IMP on the ARPNET” .

19. The Development of the Internet…. • Kahn then developed what later became the Transmission Control Protocol/Internet Protocol (TCP/IP). • As the number of nodes increased, more universities joined the exclusive club, and APRANET became not only a research facilitator, but it also became a free federally funded postal system of electronic mail. • In 1984, the U.S. National Science Foundation (NSF) joined ARPANET in starting its own network code named NSFNET. NSFNET set a new pace in nodes, bandwidth, speed and upgrades.

20. The Development of the Internet…. • This NSF funded network brought the Internet in the reach of many universities throughout the USA and internationally that would not otherwise afford the costs, and many government agencies joined in. At this point other countries and regions were establishing their own networks • With so much success and fanfare, ARPANET ceased to exist in 1989. • As the number of nodes on the Internet climbed into hundreds of thousands worldwide, the role of sponsoring agencies like ARPA and NSF became more and more marginalized. Eventually in 1994 NSF also ceased its support of the Internet. The Internet by now needed no helping hand since it had assumed a momentum of its own.

21. The Development of the World Wide Web • The World Wide Web, as we know it today, had its humble beginning from concepts contained in Tim Berners-Lee’s 1989 proposal to physicists calling for comments. • Berners-Lee, a physicist researcher wrote the proposal called HyperText and CERN, to enable collaboration between physicists and other researchers in the high energy physics research community. (CERN: Conseil Européen pour la Recherche /European Organization for Nuclear Research) • Three new technologies were incorporated. They were: HyperText Markup Language (HTML) based on the hypertext concepts- to be used to write web documents, HyperText Transfer Protocol (HTTP) a protocol to be used to transmit web pages between hosts, and a web browser client software program to receive and interpret data and display results. • His proposal also included a very important concept for the user interface. • This browser supported interface was based on the concept that it would be consistent across all types of computer platforms to enable users to access information from any computer. The line-mode interface was developed and named at CERN in late 1989 and it came to be known as the world wide web or www.

22. The Development of the World Wide Web … • By 1991, the concept developed only two years back was put into practice on a limited network at CERN. From the central computer at CERN with few web pages, the number of servers started to grow from the only one at CERN in 1991, to 50 world wide by 1992, to 720,000 by 1999, and to over 24 million by 2001 . • The graphic user interface (GUI) popularized the user and fueled the growth of the world wide web to bring it to the point where it is today.