Web Site Files
Your web site will consist of a group of computer files. Some of the files will be text, some may be images. The text files will contain the words your visitors will see as well as computer instructions they will not see.
The computer instructions — also known as programming code, source code, or merely code — provide behind the scenes information for visitors’ browsers, enabling them to display — developers prefer the word “render” — your web pages the way you intend them to be seen.
To make your web site available to the public, these files must be stored on a computer that is always connected to the Internet. Most small to midsize companies and organizations do not need to purchase and maintain a dedicated computer to house web site files. Instead, it is usually cost effective to rent storage space — a place where the public can find and view the files — which brings us to the next topic, web hosting.
Web Site Host
Your web host is the company you pay to provide storage space for your web site and to make your site available to visitors. In return for your monthly payments, your web host strives to keep their computers working 24/7 so the public will always have access to your web site (and so you’ll continue to pay your web host their service fee).
Your web host’s computer is said to serve your web pages to visitors, much like a waiter serves his customers items from the restaurant menu — your site will also have at least one menu.
Your web host’s computer is called a server, because it serves files upon request. A visitor’s computer is known as a client because its role is to request files rather than serve them.
Bandwidth refers to the load placed on the host computer. Bandwidth is influenced by the number of visitors, the number of pages they request, and the volume of information on those pages.
Bandwidth explained and tools to estimate your site’s bandwidth needs… (external link)
Presenting information efficiently to your visitors reduces the volume of information served, thus reducing the load on your host’s computer. Minimizing the host’s load minimizes the fees your host will charge you. Bandwidth costs seem to be declining. If you own a small business web site, chances are you will not need to worry about bandwidth costs. Your primary concern will be ensuring your pages are small enough to load quickly.