Post on 30-Dec-2015
Internet/Web Basics
Margie Metzlermargie@netapp.com
Java 3.3.129
(408) 822-3185
http://www.geocities.com/webclassfremont/
http://www.geocities.com/margiemetz/
April 19, 2023
What is the Internet?A World Wide Computer Network
Definitions
Internet: the largest public Wide Area Network
Intranet: a private Wide Area Network, with access restricted to those within an organization
Extranet: a private Wide Area Network for a group of companies or organizations
World Wide Web: a huge collection (all) of the HTML documents that link to other documents
What is a Network? Networking is Communicating Three Types of Computer Networks
1. Peer to Peer
2. Local Area Network
3. Wide Area Network
1. Peer to Peer
Network Cable
PC PC
2. Local Area Network (LAN)
W/S
FileServer
W/S
The computing is done on the PC’s.
The file server holds and protects
your files.
3. Wide Area Network
PC
FileServer
PC
Santa Clara
PC
FileServer
PC
Sunnyvale
Leased phone lines
So what is the Internet?
The Largest Public Wide Area Network
TCP/IP
Basic Technologies TCP/IP : Transport Control
Protocol/Internetworking Protocol. Enables one computer to address and send data to another. IP handles addressing and TCP ensures delivery.
FTP: File Transfer Protocol. Service capable of moving files from one computer to another.
SMTP: Simple Mail Transport Protocol. The basis for Internet e-Mail.
What is on the Internet? World Wide Web Sites File Transfer Protocol Sites E-mail Telnet
What is the World Wide Web?
A huge collection of HTML documents
H Hyper
T Text
M Markup
L Language Documents that link to other
documents
HTML Current standard: 4.0 (but 3.2 is what
browsers do best) See www.w3.org to see what is
standard at any time Uses open and closed brackets Is a Markup Language rather than a
Programming Language Evolved from SGML
What is a Web Page? An HTML file (text-only) The HTML file may link to:
– Graphic Files– Sound Files– E-mail addresses– Other HTML files– Etc.
What is a Web Site? A group of HTML files A folder on a hard disk A collection of Web Pages
What is a Web Server? Computer holding the Web Site Software that lets the computer serve
the site to another computer
What do I need to Use the 'Net?
Computer (PC, MAC, etc) Connection (Modem or Ethernet Card
for LAN) Internet Service Provider Software to connect to ISP Browser
– Netscape Navigator, Microsoft Internet Explorer (various versions)
...and to create web pages?
Space on a Web Server Software to upload the web site to the
server Application to create HTML (Notepad,
vi)
Don’t I Need a Web Page Designer?
No…If you know HTML you can use Notepad or vi. You
can also use Microsoft Office but ….
But…– You may want to use software such as HomeSite by Allaire,
FrontPage by Microsoft, Dreamweaver by Macromedia, Netscape’s Composer, Adobe PageMill or Go Live, or Arachnophilia (http://www.arachnoid.com/arachnophilia/), or…
– WYSIWYG Editors don’t use “standard” HTML code.
– They inject extraneous code of their own, which is tedious to edit or remove.
History of the Internet Mainframe computers start to share data Person-to-Person communication
– E-Mail – Distribution Lists
Development of a Language Development of the first browser Hypertext and Graphics Introducing the World Wide Web!
History (continued)
1969, ARPANET launched: U. of Utah, SRI, UCLA, UCSB, by Advanced Research Projects Agency (ARPA) to ensure communications in case of a nuclear war
1976, AT&T launches UUCP (Unix to Unix Copy)
1969
ARPANET
1976
Packet switching
and UUCP
1983
TCP/IP
1990
ARPANET
dissolved
1984
DNS2001
We are
here!
1979
Usenet1986
NSF1992
WWW
History (continued) Usenet, 1979: UUCP link between Duke
and UNC
TCP/IP in 1983: >500 hosts
1984, Domain Name System (DNS) is introduced for automatic address resolution
1986: National Science Foundation creates NSFNET
1992: World Wide Web (>1,000,000 hosts)
World Wide Web
Developed at CERN, early 1990’s European laboratory for Particle
Physics Proposed by Tim Berners-Lee in 1989 Prototyped on NeXT (1990) Launched in 1992 Mosaic introduced in 1993
Components of a Web Site
Basic Web Pages (HTML)
Documents– Acrobat– HTML– Office
Components of a Web Site
Other– Forms– CGI scripts– Server-Side Scripting (CGI’s: PERL,
C++ etc.)– Client-side Scripting (JavaScripts)– Security (firewalls etc.)
Creating your site Get a domain name Get a server to serve your pages Create your HTML pages Upload them to your server
The Internet Challenge: Communicating Globally
Networks Operating systems Workstations Software People
Talking...
Major Issues
You can’t control what people see– They use different browsers: Netscape, Internet
Explorer, Lynx, Opera (and different versions)
– They can turn off graphics and change text colors and sizes on their browsers
– Mac, UNIX, PC operating systems give users much different views
– Servers don’t always support your HTML code. (60% are UNIX running Apache)
– They don’t like being required to download plug-ins
– They use different monitors/screen sizes/resolutions
Who’s Using What? Servers: 60% UNIX running Apache, probably greater in
Silicon Valley. The rest are other and Microsoft NT servers.
Browsers: (http://www.statmarket.com/SM?c=stat022201):
“As of Feb. 21, 2001, Microsoft Internet Explorer's usage share was 87.71 percent worldwide, up from only 86.08 percent on June 18, 2000, according to WebSideStory's StatMarket, the recognized authority on global Internet user trends. Netscape's global usage share, meanwhile, was 12.01 percent on Feb. 21, down from 13.90 percent in June. Usage share is the percentage of people worldwide that are using a particular browser on the Web.”
Microsoft
Netscape
Other
Who’s Using What?(http://browserwatch.internet.com/stats.html):
Browser Types Visiting BrowserWatch
(Must Have .25% Share Or Better)Browser Value Percent
Microsoft Internet Explorer 4291 68.8%
Netscape Navigator 1083 17.3%
Opera 218 3.49%
4.72 (X11) 94 1.50%
AvantGo 3.2 84 1.34%
IBrowse 50 0.80%
Powermarks-3.5) 48 0.77%
JennyBot 47 0.75%
MSProxy 27 0.43%
FavOrg 23 0.36%
Lynx 23 0.36%
Graphics: Types
GIF: Graphical Interchange Format (CompuServe)
JPEG: Joint Photographer’s Experts Group
PNG: (W3C)
More on Graphics Monitors: resolutions of 640x480 to
1600x1200 Pixels: basic building blocks A pixel has complete set of red, blue
and green dots Size of pixel depends on the video
card, how the hardware is configured, and size of the screen
More Graphics
Color models:– Pantone (Print media)– RGB (Red, Blue, Green.) Monitors– CYMK (Cyan, Magenta, Yellow and
Black.) Printers 216 Web-safe colors
Still More Graphics Resolution Bandwidth File size: shouldn’t be over 50-60 KB.
(Users don’t like downloading big graphics unless they’re really necessary.)
Usability Issues How well can users use your site? Some of the rules we’ve used for print
no longer apply.
Usability Definitions
Usability describes whether people can achieve their goals in a simple and pain-free manner.
Six Attributes of Usability
Learnability - System enables achieving tasks on first time use
Success - System enables the user to complete work without errors
Throughput - System enables rapid completion of work
Satisfaction - System is pleasant to use System Integrity - System does not enable
the user to injure it Health and Safety - System does not enable
the user to injure herself
Usability Issues
Audience– Line speed?– Firewall issues?
Special Technology Requirements– Plug-Ins?– Bells & whistles?
Develop for the lowest common denominator
Writing for the Web
Web Facts 79% of users always scan; only 16%
read word-by-word
Reading from computer screens is 25% slower than from paper
Web content should be 50% the size of its paper equivalent
Paper vs. Online Publishing
Paper
Document forms a whole, and the user is focused on the entire set of information
Paper vs. Online Publishing
Web Site Publishing Split documents into multiple hyperlinked pages Make sure each page stands on its own Lower word count; readers read about 25% slower Get to the point: Web users are task-oriented and
impatient Don’t exaggerate: Credibility is critical Use an informal and immediate writing style Use simple sentence structures Update pages often Use up-to-date statistics, numbers and examples
Screen Size. 100 words on a Palm-sized computer is a lot to read. The same text at 1024 x 768 is a reasonable amount.
Resolution. Print text is 600 dpi. Online text is 72 dpi. This difference produces a jagged text that is more difficult to read and tires eyes.
"Noise." Everything on screen that distracts from the message of the content: banner ads, animations, meaningless graphics, and formatting are all "noise".
Issues that Affect Writing Style
Choose appropriate fonts and colors.
Use online fonts and Web-safe colors.
Use Meaningful sub-headings.
Use Bulleted lists.
Use only one idea per paragraph.
Chunk information together.
Use half the word count of conventional writing.
Writing Suggestions
Simplicity
Credibility
Outbound links
Humor: But use with caution (remember “World-Wide”)
Speed: Users want to get their information quickly
What Users Want
(Spool, Jared et al, Web Site Usability, p. 75.) The more white-space there was on a site, the less successful
users were at finding information
The more white-space, the lower users rated the site in terms of:– Finding things easily– Ease of reading– Ease of searching– Overall appearance– Ease of use– Productivity
Why? Skimming is different from reading. People are “hunting” for information on the Web. White-space spreads out information and slows the “hunt.”
White Space
Conventional wisdom: people don’t like to scroll, hence information should not be “below the fold,” in newspaper parlance, or below the screen such that you have to scroll to read.
Not true:
– Different sized screens, resolutions etc. make it impossible to know how big anyone’s screen is.
– Usability studies show no one minds scrolling down. (They do get annoyed at strolling across, however…).
– But… users quit reading when they hit a horizontal line or a line of very small text.
Scrolling
Studies indicted that graphic design has no impact on a site’s usability.
But…. users reported that they couldn’t concentrate when there was animation on the screen.
Graphics
You lose 75% of your readers on each click they have to make to find information.
However, readers will continue to click if they think the link will take them to the information they want.
Links
Skills needed HTML, JavaScript, Java, PERL
programming Writing for the Web Design Management of Internet, Extranet,
Intranet Graphic artists
That’s All, Folks!