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CS 101 – Dec. 2 • Download speed • Internet vs. Web • Domains • HTML

CS 101 – Dec. 2 Download speed Internet vs. Web Domains HTML

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Page 1: CS 101 – Dec. 2 Download speed Internet vs. Web Domains HTML

CS 101 – Dec. 2

• Download speed

• Internet vs. Web

• Domains

• HTML

Page 2: CS 101 – Dec. 2 Download speed Internet vs. Web Domains HTML

Measuring speed

• Overhead = prepare & assemble message

• Flight time = first bit to arrive at destination

• Bandwidth = max rate to propagate data

(cruising speed)

• Total time =

overhead + flight time + (msg size)/bandwidth

Page 3: CS 101 – Dec. 2 Download speed Internet vs. Web Domains HTML

How much longer?

File Size Progress “time left” rate

#1 815 KB 65.1% 3:08 1.5 KB/s

#2 5.9 MB 64.8% 24:03 1.5 KB/s

Page 4: CS 101 – Dec. 2 Download speed Internet vs. Web Domains HTML

Examples

Page 5: CS 101 – Dec. 2 Download speed Internet vs. Web Domains HTML

Hypertext

• A text document that contains links to other documents.

• Also may contain “multimedia”

• Filename *.html

• Software: editor…browser.

Page 6: CS 101 – Dec. 2 Download speed Internet vs. Web Domains HTML

Some terminology

• Internet = global “network of networks”

• Some Internet applications:– WWW = linked documents on the Internet– E-mail– chat– FTP = file transfer prototcol

Page 7: CS 101 – Dec. 2 Download speed Internet vs. Web Domains HTML

Web terminology

• HTML = standard language for hypertext

• Web page = hypertext document (*.html)

• Web site = collection of pages & folders usually starting with index.html

• Web server = machine containing site

• Web browser = program that interprets HTML to show on screen

Page 8: CS 101 – Dec. 2 Download speed Internet vs. Web Domains HTML

Web addressing

• Location of file is given by a Web address or URL.

http://www.seds.org/billa/tnp/saturn.html

• saturn.html = page

• billa/tnp = folders

• www.seds.org = site [ server.place.domain]

Page 9: CS 101 – Dec. 2 Download speed Internet vs. Web Domains HTML

Domains

• Three letter for U.S. (.com, .org, .net, .edu, .mil, .gov)

• Two letter for countries (.ca, .uk, .za, .ch, .de, .is, cn, .at, .us ………)

• Beware of exceptions

• Newer domains (.info, .museum, .biz, …)

Page 10: CS 101 – Dec. 2 Download speed Internet vs. Web Domains HTML

Making Web pages

• Web pages written in HTML. 2 ways…

• Type in HTML code in text editor.– Enter “tags” as you go.

• Use “web generator” such as Dreamweaver– WYSIWYG

Page 11: CS 101 – Dec. 2 Download speed Internet vs. Web Domains HTML

HTML format

• Web browsers read HTML files.

<html>

<head> ... </head>

<body> ... </body>

</html>

• Head section is optional• Body contains material to appear in browser

window.

Page 12: CS 101 – Dec. 2 Download speed Internet vs. Web Domains HTML

Minimal example

• The simplest Web page contains text.– Can format with various font commands …

<html><body> Hello!</body> </html>

Page 13: CS 101 – Dec. 2 Download speed Internet vs. Web Domains HTML

Common tags

• h1, h2, etc. = headings

• br = line break

• p = paragraph

• ol, ul, li = used for lists

• hr = horizontal rule

• b, i = bold or italic

• sub, sup = subscript or superscript

Page 14: CS 101 – Dec. 2 Download speed Internet vs. Web Domains HTML

Examples

• 7 <sup> th </sup>

• Who wrote <i> Das Rheingold </i> ?

• <ul>

<li> Gold </li>

<li> Silver </li>

<li> Bronze </li>

</ul>