Learn PHP - Lesson 1 Tutorial - How to get started with PHP - Part 1, The Internet
There are basics one must know when getting started with PHP.
In this lesson, we will cover the following:
1) At a minimum you need a high level understanding of what makes up that which we call the internet
2) Understand the basics of what constitutes a web server (at least as far as we're concerned to get your coding)
3) The two easiest ways for you to start creating php web applications.
4) Learn how to create a php page.
Here is a high level overview of the internet starting with your computer.
To connect to the internet, your computer sends a request to your ISP. For example - a request would be what you type in internet explorer's address bar. Let's say you typed in www.phphaven.com and hit enter. You just sent a request for that web site. (Figure 1 below).
Now, let us assume now one has requested that site before, it's a brand new web site. This means your ISP doesn't know where that web server is and must request a location from one of the main root servers on the internet. There are over 14 main root servers that handle requests in the world. Your request for www.phphaven.com was just sent to the closest one.
Figure 2 below.
It's important to note that root servers don't actually keep records of the location of the web servers the request is on. What they do keep is the location to the TLD server that will know where your request is (TLD stands for Top Level Domain). And the Root server tells your ISP what TLD server to communicate with in order to get the information it needs. Your ISP then sends the request to that TLD server.
Figure 3 below.
The TLD server looks up the request and returns it back to the ISP. The ISP then sends your request on to the web server, it returns the website you want to look at (the request) back through your ISP and the ISP then forwards it on to your computer. NOTE: Once your ISP knows where your request is, it's caches that information; this way it doesn't have to ping the root and TLD servers over and over again. Also note the shaded area is a simplistic look at what we consider the internet.
Figure 4 below.
click here - full size
Please understand that this is an attempt to simplify how things work on the internet for someone who is considered a beginner. Please only constructive criticism as I realize there are many other factors involved in what makes up "the internet".
That wraps up lesson 1 - part 1... enjoy.
Go to Part 2 »
« Back to Table of Contents