1. COMP 101 Introduction

2. The Team

3. Enrolling

4. The Website

5. The Class

6. How a Computer Works It is actually a very simple machine:
It executes exactly what it is told to do
Rather like Forrest Gump

7. Seriously, … Computers Execute algorithms Need to be told what to do
And to whom to do it

8. Algorithm
Just a recipe
What do recipes do?
Steps
Tests
Repetitions

9. Internet

10. What is the Internet?
The machines
The connections
The content

11. The Internet in 1980

12. The Internet Circa 1998

13. What made the Internet succeed?
Early users shared information
Command lines
1993: Browser invented!
Mosaic
Marc Andressen
Brought
Graphical Interface
Easy access
No technical skill needed

14. Browsers

15. Viewing a Web Page
Server
Web Server
Pages
SERVER web page repository WEB PAGE instructions stores information and instructions BROWSER retrieves web page and follows instructions 2 1 3
Client
Browser

16. Viewing a Web Page
Server
Web Server
Pages
SERVER web page repository WEB PAGE instructions stores information and instructions BROWSER retrieves web page and follows instructions 2 1 3
Client
Browser

17. What is http and https? HyperText Transfer Protocol
Protocol: set of rules
Transfer: move it from one place to another
Hypertext: the essence of the web – the links
HTTPS is the secure version
Tells the browser that it has to go to the internet to find it

18. Retrieving a web page That’s a file You type the URL
How does your computer find it?
Up to the first slash is the SERVER name
Everything after that is folders until the last one
That’s a file

19. Routing: Getting to the Server
Server names don’t tell me where anything is
They DO tell me who gave them the name
cs.unc.edu:
organization that manages edu gave the university unc
Unc gave the department cs
Translate the name to a number called the IP address
Example:
Each value ranges from 0 to 255!
Translation is done through a table called the Domain Name System (DNS)

20. Browser Instructions

21. What do the instructions look like
Open Chrome
We want to look at a page
View Page Source
Only TEXT
Even though the page has a picture on it!

22. Web Instructions: Three Legs
HTML
Content
CSS
Presentation
JavaScript
Behavior

23. Creating HTML All we have to do is edit a page
CANNOT use a word processor
Word, Pages, Writer
Why? They add all sorts of gorp
Do NOT need special software
We WILL use it: Komodo Editor
It HELPS

24. First Step Need to be able to put content on the web FILE TRANSFER
Work on your machine and then post it so the world can see