1. The Links that Becamea WebThe 40-year Old Internet and the 20-Year OldWebEDU626 Integrating Educational Technology Summer 2013
2. First: What is the Internet?For one thing, it‟s not really “thenet”, it‟s the “nets”:– The internet is “a cooperatively-runcollection of computer networks thatspan the globe.”2
3. A formal definitionInternet– The high-speed fiber-optic network of networksthat uses TCP/IP protocols to interconnectcomputer networks around the world, enablingusers to communicate via e-mail, transfer dataand program files via FTP, find information onthe World Wide Web, and access remotecomputer systems such as online catalogs andelectronic databases easily and effortlessly,using an innovative technique called packetswitching. The Internet began in 1969 asARPAnet, a project of the U.S. Department ofDefense.
4. Cold War Technology?Originally designed by the U.S. Department ofDefense so that a communication signal couldwithstand nuclear war and serve militaryinstitutions worldwide, the Internet was firstknown as the ARPANet, the most robustcommunication technology. It is a system of linkedcomputer networks, international in scope, thatfacilitates data transfer and communicationservices, such as remote login, file transfer (FTP),electronic mail (e-mail), newsgroups, and theWorld Wide Web. The Internet greatly extends thereach of each connected computer network (see:network effect, IP).– Internet
5. Before ARPANetBefore ARPANET, most computer systems consistedof a massive computer -- sometimes the size of anentire room -- with user terminals hardwired to it. Aterminal was some form of user interface, oftenconsisting of a keyboard or punch card reader.Multiple users could access the computersimultaneously, in a technique called timesharing.Other early networks required a direct connectionbetween host computers, meaning that there wasonly one path for information to flow through. Thedirect connections limited the size of these computernetworks, which became known as local areanetworks (LANs).– How ARPANET Works
6. Phone-linked networks“In the 1960s, as many as a few hundredusers could have accounts on a single largecomputer using terminals, and exchangemessages and files between them. But eachof those little communities was an island,isolated from others. By reliably connectingdifferent kinds of computers to each other,the ARPANET took a crucial step towardthe online world that links nearly a third ofthe worlds population today.”– Marc Weber, founding curator of the Computer HistoryMuseum‟s Internet History ProgramOn October 29, 2009, SRI celebratedthe 40th anniversary of the firstARPANET connection.
7. From mainframes to minicomputersBefore ARPANET, most computer systemsconsisted of a massive computer -- sometimes thesize of an entire room -- with user terminalshardwired to it.What is amainframecomputer?
8. The 1957 vision of computers
9. Minicomputers?Minicomputers are a largely obsolete class ofmulti-user computers which made up themiddle range of the computing spectrum, inbetween the largest multi-user systems(mainframe computers) and the smallestsingle-user systems (microcomputers orpersonal computers).From Blog “Health CareRenewal”:[a] picture from the GeorgeWashington High School(Phila., PA) 1973 yearbook infront of [their] high schoolsDEC PDP-8/S:
10. When did ARPAnet become the Internet?“. . . Ray Tomlinson is credited withinventing email in 1972. . . . He pickedthe @ symbol from the computerkeyboard to denote sending messagesfrom one computer to another. Sothen, for anyone using Internetstandards, it was simply a matter ofnominating name-of-the-user@name-of-the-computer.“. . . 1975 seems to be the definitiveyear in which, for the first time,networks connected to each other.”– Ian Peter‟s History of the InternetMeet the Man Who Putthe „@‟ in Your E-MailBy Cade Metz07.30.12
11. 1975, the net goes commercialTelenet– One of the first value-added, packet switchingnetworks that enabled terminals and computersto exchange data. Established in 1975 by Dr.Lawrence Roberts, who helped to developARPANET, Telenet was acquired by GTE in1979. After it was acquired by Sprint in 1986, itwas renamed SprintNet
12. Packet switching?Almost like USPS delivery– In a packet-switched network, no circuit is setup prior to sending data between devices.Blocks of data, even from the same file orcommunication, may take any number of pathsas it journeys from one device to another.Compare this to Figure 1 [circuit switching isessentially a direct connection]
15. 1980sMain uses scholarly or military– Libraries use Telenet and Tymnet forremote searching of databases– Scientists and scholars communicate byemailThe Silent 700 was a line of portablecomputer terminals manufactured by TexasInstruments in the 1970s and 1980s. Silent700s printed with a dot-matrix heatingelement onto a roll of heat-sensitive paper.They were equipped with an integratedacoustic coupler and modem that couldreceive data at 30 characters per second.
16. What, no fun things?Enter the BBS!– Bulletin Board System– A forum for users to browse and exchangeinformation. Computer BBSs are accessible bytelephone via a personal computer and amodem. Many BBSs are small operations runby a single person that allow only several usersto log on at the same time. Some are muchlarger and allow hundreds of users to loginsimultaneously to use the system. Huge,commercial examples are America Online,CompuServe, and Prodigy.• From Glossary of Distance Education and InternetTerminology
17. BBS all text, very little graphics
18. Related to BBSGopher– The Gopher Protocol is a distributed documentsearch and retrieval protocol that wasdeveloped at the University of Minnesota in thelate 1980s. Resources are stored on Gopherservers, which organize information using ahierarchical directory structure. Gopher clientsaccess servers to retrieve directory listings ofavailable resources, which are presented to theuser as a menu from which an item may beselected for retrieval.• Gopher Protocol (Gopher) (Page 4 of 4)
19. A Gopher menuHong Kong Baptist University‟s Home Gopher MenuTo navigate the menus, you used the arrow keys (no mouse, of course!) tomove the arrow up or down the menu and then hit Enter to select the itemyou wanted. Current browsers no longer support Gopher.
20. Veronica, Jughead and Archie!Rodent companions (note: no Betty)!– Veronica: “Very Easy Rodent-Oriented Net-wide Index to Computerized Archives”– Jughead: “Jonzy‟s Universal Gopher HierarchyExcavation and Display”– Archie: a popular FTP [“File TransferProtocol”] search program of the time. Thoughthe legend of Archie being named for thecartoon, the name in fact is shorthand for“Archives.”• A Pre-Web Search Engine, Gopher Turns TenBy Chris Sherman, Search Engine Watch, Feb 6, 2002
21. The Web is added: 1991Tim Berners-Lee:– “. . . in 1989, while working at the European ParticlePhysics Laboratory, I proposed that a globalhypertext space be created in which any network-accessible information could be refered to by a single“Universal Document Identifier”. Given the go-aheadto experiment by my boss, Mike Sendall, I wrote in1990 a program called “WorldWideWeb”, a pointand click hypertext editor which ran on the “NeXT”machine. This, together with the first Web server, Ireleased to the High Energy Physics community atfirst, and to the hypertext and NeXT communities inthe summer of 1991.”• The World Wide Web: A very short personal history
22. The first “real” browserNCSA MosaicIn 1991, the NCSA introduced NCSA Mosaic, thefirst readily-availablegraphical Web Browserthat virtually kickstartedthe dot.com revolution. Itmay not look like muchnow - but it is interestingto consider how similarmodern browsers look tothe original.PawPrint.net Glossary of Terms
23. Today‟s browsers
24. Alphabet soup of the WebURL– Uniform Resource LocatorHTTP– HyperText Transfer ProtocolHTML– Hypertext Markup Language– Now being complemented by XML• EXtensible Markup Language– See What is XML?
25. Basic URL StructureParts– A URL has three basic parts: the protocol (how to get the resource);the server id (who to get the resource from); and the resource id (thename of the resource and how to find it on the target machine). In itsmost basic form, this looks like the following:– The "http" indicates that this is a Web document. The"www.fake.com" is the domain name of the (in this case, fictional)machine on which the web server is running (we know it‟s a webserver because of the protocol). And, of course, “doc.html” is thefilename of the HTML document (notice the file extension “.html”)on that machine.
26. Other url address typesGopher URLs– gopher://gumby.brain.headache.edu:151/7fonebook.txtAccess the searchable index “fonebook.txt” from thenamed gopher server, running on port number 151.[It‟s unlikely that you will be access this: most modern browsersno longer support gopher]Mailto URL– mailto:user@host?subject=Happy%20lobsters[Allows you to] include mail headers within the mailtoURL. [This] example [will] send a letter with thesubject line “Happy lobsters”.• For other examples, see Uniform Resource Locators (URLs) fromIntroduction to HTML by Ian Graham, The Information Commons,University of Toronto. Last Update: 20 September 2000
27. Domain name?What is a „Domain Name‟?– Domain Name System, or DNS, is the mostrecognized system for assigning addresses toInternet web servers (aka “Internet hosts”).Somewhat like international phone numbers,the domain name system helps to give everyInternet server a memorable and easy-to-spelladdress. Simultaneously, the domain nameskeep the really technical IP address invisible formost viewers.• By Paul Gil, About.com Guide
28. Structure of a Domain Name 1Top-level domain or first-level domain– Every domain name has a suffix that indicates theTop Level Domain (TLD) to which it belongs. TheTLD is the part of an internet domain name whichcan be found to the right of the last point. GenericTLDs include .com, .int, .net, .info, .org, etc. Thereare also many country code top level domains(ccTLDs) such as .es, .it, .cz and .be. Each TLD isassociated with a particular registry whichregisters the names associated with the TLD.• What is a Top Level Domain (TLD)?• The .eu Top Level Domain
29. Structure of a Domain Name 2Second-level domain– In the Domain Name System (DNS)hierarchy, it is the highest levelunderneath the top-level domains. It isthat portion of the domain name thatappears immediately to the left of thetop-level domain, separated by a dot.For example, the “NetLingo” inwww.netlingo.com is a second-leveldomain.
30. Structure of a Domain Name 3SubDomain - The Third Level Domain– If you need to further distinguish yoursecond-level domain name, you can use athird-level domain name, such as“resources.hostway.com.” Typically athird-level domain name is used to referto different servers within differentdepartments of a company.• Creating third-level domains
32. Success of the web?Tim Berners-Lee:– The success of the World Wide Web, itself built on the open Internet, hasdepended on three critical factors: 1) unlimited links from any part of theWeb to any other; 2) open technical standards as the basis for continuedgrowth of innovation applications; and 3) separation of network layers,enabling independent innovation for network transport, routing andinformation applications. Today these characteristics of the Web are easilyoverlooked as obvious, self-maintaining, or just unimportant. All who usethe Web to publish or access information take it for granted that any Webpage on the planet will be accessible to anyone who has an Internetconnection, regardless whether it is over a dialup modem or a high speedmulti-megabit per second digital access line. The last decade has seen somany new ecommerce startups, some of which have formed the foundationsof the new economy, that we now expect that the next blockbuster Web siteor the new homepage for your kids local soccer team will just appear onthe Web without any difficulty.• Testimony of Sir Timothy Berners-Lee, Hearing on the “Digital Future of the UnitedStates: Part I -- The Future of the World Wide Web”
33. The Internet is a far more speech-enhancingmedium than print, the village green, or themails. . . . The Internet may fairly be regardedas a never-ending worldwide conversation.Statement by a federal judge in American CivilLiberties Union v. Reno, 929 F. Supp. 824, 844 (E.D. Pa. 1996)(Dalzell, J.). Quoted by Tim Berners-Lee in his Testimony atHearing on the “Digital Future of the United States: Part I --The Future of the World Wide Web”The internet a conversation?