1. ITIS 1210 Introduction to Web-Based Information Systems Chapter 4. Understanding the Internet’s Software Structure

2. Understanding the Internet’s Software Structure  Internet uses a “Client-Server” model  Client  Needs services  Server  Provides services  Delivering Web pages or email

3. Understanding the Internet’s Software Structure  Client  Local personal computer  Server (host)  Many manufacturers & models  Multiple operating systems  Usually far more powerful than a “normal” PC

4. Understanding the Internet’s Software Structure  Why servers?  So all clients don’t have to have the same capabilities  Many clients can access the same files or programs on a single server  For WWW  Client is browser running on your PC  Server is a Web host somewhere on the Internet

5. Understanding the Internet’s Software Structure  Browser  Sends request (for a Web page or file) to a server  Server  Processes request  Sends answer back to client  Client displays data from server

6. Understanding the Internet’s Software Structure  PC-based browser program controls client end  Browser requests a Web page from the server  Server processes request  Host computer (server) houses the Web site  Server sends requested data back to originating computer  Software enables the server to retrieve specific pages and transmit them to clients

7. Understanding the Internet’s Software Structure  To a client, the Web appears to be  Limitless file storage mechanism  Distributed among thousands of computers  Accessible to anyone with an Internet connection