INTERNET A collection of networks
History ARPANet – developed for security of sending in case of a nuclear attack IDEA – the system would not go down
Characteristics Not all units directly connected Client/server type of connectivity Makes use of a router Makes use of a gateway Information transmitted by packets
What is the first step in becoming an Internet user? Subscribe to an ISP Internet service provider
What am I buying? Three basic services
telnet FTP
Definitions Telnet – allows communication with remote computers FTP – file transfer protocol – communication software
You also get 2 protocols: 1.IP 2.TCP
Definitions IP – internet protocol refers to type of topology defines a packet to be 1500 bytes does the routing TCP – transmission control proto Transmission will be through a sequence of packets Assembles and disassembles the packets
What else do I get? Software that is used to explore the Internet A Browser
Can I get anything else? Software that adds to the browser (video) A Plug-In
Additional software – SEARCH ENGINE Software that builds a database of searchable terms USES A SPIDER???
Search Engines Vary InfoSeek – searches newsgroups, FAQs, and addresses in addition to Web sites AltaVista – indexes every word on a page Excite – provides related hints and extra content Google – results ranked by algorithm based on number of links from other pages Lycos – numerous search options/a comprehensive directory HotBot – excels at finding current news/fast Northern Light – group results by subject, type, source, and language
Two with the Broadest Coverage
Directories YAHOO Sites are organized by content category
Metasearch Engines MetaCrawler Dogpile Software that searches the search engines
Boolean Logic Narrowing the search
Do I have access to the World Wide Web? You might And you might not
World Wide Web (WWW) provides a uniform type of access to all Internet services A type of GUI (graphical user interface) Characterized by HTML
HTML hypertext markup language Hypertext – allows access to other addresses by pointing and clicking on a picture or text The address is attached through the code of the hypertext format <A HREF = main menu main menu is the text which should be highlighted to access this address
Other HTML symbols Goes at the beginning of the document and at the end to define it as using hypertext protocol Beginning and end of heading section Beginning and end of bold text
If a website does not use the World Wide Web, it still has the same services. Access is no longer through graphics. Access is now done through a series of menu options. Important point.
JAVA A programming that allows permits dynamic Web pages
Allows the following: dancing icons sound clips flashing messages scrolling banners applets – programs that provide code for these features ActiveX controls – Microsoft feature that provides the same features
WARNINGS Must have a browser that is capable of running these applets Applets present some security risks.
Disadvantage Not as user friendly. Advantage Downloading time will be less. Not downloading pictures, colors, etc.
Internet Addresses URL’s (uniform resource locators) Each is an IP number.
COMGOVNETORGMILEDU
BIZUKPRONAMEAERODE Country designators COOPINFOMUSEUM
COMGOVNETORGMILEDU
NETWORK of DOMAINS Creates A MESH TOPOLOGY
DOMAIN Defines use of hypertext protocol Individual computer Subdivision of the individual computer
DOMAIN Defines use of hypertext protocol Individual computer File (web page) to get
Wireless Internet Access Types of devices Text pagers PDAs – personal digital assistants Pocket computers Web enabled cellular phones
Wireless Internet Access Additional hardware/software needed: Account with wireless access service provider Cellular modem card or adapter Problem – limited display area Wireless Application Protocol – used by providers to convert Web pages to capabilities of hand held devices