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Global Applications

Explore the historical journey and foundational concepts behind computing, the birth of the Internet, email communication, World Wide Web, and other key applications. Understand the evolution of technology and its social impact.

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Global Applications

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  1. Global Applications CS 105

  2. Introduction • The growth in computer speed, power, and pervasiveness took even the experts by surprise. • I think there is a world market for maybe five computers — Thomas Watson, chairman of IBM 1943 • Where a calculator like the ENIAC is equipped with 18,000 vacuum tubes and weighs 30 tons, computers in the future may have only 1,000 vacuum tubes and perhaps weigh 1.5 tons – Popular Mechanics, ca. 1947 • There is no reason anyone would want a computer in their home – ken Olson, president, chairman and founder of Digital Equipment Corp., 1977

  3. History and Technology • In the cold war days of 1960s, the U.S. Department of Defense decided the country needed a national network connecting the scores of government and research computers. • The network had to be decentralized. • If one computer went down, the rest of the system would adapt by passing messages around the inactive site. • The Addressing System that we are using today in Internet was invented at that time.

  4. Internet • What later become known as Internet was born as ARPANET in 1969 connecting four host Computers at UCLA, UCSB, Univ. of Utah and Stanford. • Internet: Network of networks.

  5. How does it work? • IP Address • Message • Packets. Why? • Format of Packets. • TCP (Transmission Control Protocol) • DNS (Domain Name Server) • Responsibilities of TCP vs. IP

  6. E-Mail • Originally, email was thought to be nothing more than a minor feature, but email grew to be a large source of traffic on the Net. • SMTP (Simple Mail Transfer Protocol) • Alice sends an E-mail to her friend Bob.

  7. E-Mail • Email is faster than the postal mail, but slower than talking over the phone or conversing in person. • Any new technology brings with it a set of social consequences that are determined by the nature of the technology itself. • We have no way of verifying the person who sends the email. • Internet robots can collect email addresses. • Social consequences eventually bring about laws governing acceptable and unacceptable behavior.

  8. E-Mail • Different mail client program: • Unix: pine • Web-based email systems • Store messages in the remote server or download messages into local drive. • Email messages can be plain ASCII text or HTML format. • HTML can include text, pictures, and links to web pages. • HTML email can carry a Web bug: an invisible piece of code that silently notifies the sender about the user’s information.

  9. Mailing List • Mailing lists enable you to participate in email discussion groups on special-interest topics. • Lists can be small and local, or large and global. • They can be administered by a human being or automatically administered by programs.

  10. E-Mail • Don’t write something in E-mail which you don’t want to be appeared some where else. • Don’t broadcast email you receive unless you first have the sender’s permission.

  11. World Wide Web • www consists of a vast number of computers connected to internet. These computers all have software, known as browsers, that allows them to send and receive documents according to a protocol known as the Hypertext Transfer Protocol (HTTP). • Hypertext ?

  12. Factors in Web Growth • Easy to use • Easy to Search • Easy to make a webpage

  13. HTML • A webpage is described as an ordinary text document containing a number of html tags. The document is called HTML document. • Tags are sequence of characters which are interpreted in special ways specifying format of the text, links, images, sound and so on. • HTML (Hypertext Markup Language)

  14. HTML • A browser can read HTML document and present it as specified by the html tags. • A html document is not a WYSIWYG. • Example • We have more on this in next module.

  15. Other Applications • Blog • Is information that is instantly published to a Web site. Blog scripting allows someone to automatically post information to a Web site. Many people will read it and they may post responses.

  16. Other Applications • Instant Messaging: real time communication • It is synchronous communication. • Email and newsgroups are asynchronous: sender and receiver do not have to log on at the same time.

  17. Other Applications • Voice over IP (also called VoIP, IP Telephony, Internet telephony, and Digital Phone) is the routing of voice conversations over the Internet or any other IP-based network.

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