The Internet

Presented byFrank H. Osborne, Ph. D.

© 2005

Revised July 2010 by

Jeanne Osborne

ID 2950Technology and the Young Child

Early origins

• 1957 – Advanced Research Projects Agency established in response to Soviet Union’s technology with the Sputnik Satellite in order to regain the US technology superiority. It was realized that the agency had to bring together the brain power found at universities and research institutions.

• Early 60’s work included ideas of sending information using packet switching where messages are broken down into smaller packets, moved to a destination and then reassembled.

• First packets sent by Charley Kline of UCLA in October 1969

• December 1967 – Defense Department issued at $19,800 contract for the purpose of studying a designed specification for a computer network.

• Email was adopted in 1972 with the @ symbol used to connect user name and address.

• BITNET connected IBM main frame computers around educational communities to provide mail services in 1981.

• The first commercial email carriers began in late 1988.

• Telnet protocol enabled one to log onto a remote computer.

• FTP allowed for file transfers between internet sites. It is still used today to upload files to a server.

• Archie was a system designed at Mc Gill University in 1989 to be a method for searching ftp files for information. In a way, it is the pre-cursor to search engines.

• In 1991, the University of Minnesota introduced a simple menu to access files and information; this was known as gopher. It was easier to find information than was previously done with UNIX.

Complete vision of the internet puzzle

• Delphi – first commercial online service to offer internet access in 1992.

• Bill Gates (Microsoft founder) released Windows 98 which included a browser in June 1998.

TCP/IP

A protocol is a set of rules that are used to transmit information on the Internet.

Services include http, ftp, gopher.

Information is sent in small electronic packets which are sent throughout the internet using routers.

To connect networks, a gateway computer is used.

Internet Addressing—The URL

• The URL is the Universal Resource Locator or Internet address for a particular location on the Internet.

• The URL was developed at CERN (European Organisation for Nuclear Research) which created the technological basis for the World Wide Web.

Internet Addressing—The URL

• IP address– The IP address consists of four sets of

numbers punctuated by dots.– Example: 131.125.1.1 is the address for the

Kean University web server also known as turbo.

– The turbo server contains the Kean Website.– In this example the 131.125 part refers to

Kean while the remaining numbers reference individual servers.

Reading a URL (1)

• Parts of a URLservice: // hostname / directory-path• Service: will be http or ftp.• // - a UNIX separator indicating that the

location is on a different computer• hostname is the name of the host computer

where the file you seek is to be found.• / is the UNIX separator for directories

(compared with DOS which is \)• directory-path tells the route to the file

Reading a URL (2)

• URL for Dr. Osborne's ID2950 Websitehttp://www.kean.edu/~fosborne/ID2950• http:// - indicates hypertext transmission

protocol• www.kean.edu

– www – indicates the server or location of the file

– kean – is the domain name of the host computer

– edu – is the zone that indicates an academic site

Reading a URL (3)

• URL for Dr. Osborne's ID2950 Websitehttp://www.kean.edu/~fosborne/ID2950/• ~fosborne/ID2950/ – is the directory path. • A directory is like a drawer in a file cabinet. It

may contain other drawers, or it may contain files.

• ~fosborne –is the main directory assigned to Dr. Osborne

• ID2950 is a directory within the main directory. It contains files for ID 2950.

Reading a URL (4)

• URL for Dr. Osborne's ID2950 Websitehttp://www.kean.edu/~fosborne/ID2950/ID2950_home_page.htm

ID2950_home_page.htm is the name of a particular file.

• A browser will display the entire pathname as shown above.

• The name of the particular file you are viewing is found all the way to the right.

• HTML internet files generally end in .html or .htm

URL Rules (1)

• Spaces are not allowed in a URL.

• A filename with a space will cause the following effect: (%20)

• (In ASCII the space character is 32 in base 10—the equivalent of 20 in hexadecimal.)

• Spaces are permitted in file names but a browser will fill each space with %20.

URL Rules (2)

• You may have a file in your directory called my best file.htm

• If you look at it with a browser the browser will show its filename as my%20best%20file.htm

• Two ways around this problem are:– MyBestFile.htm– my_best_file.htm (note that the "_" is the

underscore character)

How the Internet finds things

• You type the complete pathname of a location into your browser.

• A DNS (Domain Name System) Server will translate the domain name into an IP address for the item.

The End