A Simple Introduction to Using Computers By Ron Savage My website's URI: https://savage.net.au/index.html. This article's URI: https://savage.net.au/A.Simple.Introduction.to.Using.Computers.txt. This article is quite brief. A long version is online at: https://savage.net.au/misc/The.Dark.Side.of.Using.a.Computer.txt. And yes, the files on my website are on a case-sensitive file system. Advanced information is available at the URI: https://savage.net.au/misc/Digital.Security.Wiki.html. Digital.Security.Wiki.html is an example of a Wiki, which is a web page containing a very clever program which gives you many useful features. Specifically, I always use TiddyWikis, from https://tiddlywiki.com/. Learning to use a computer is, unfortunately, a long & complex process. You have been warned. In this article I will present my advice in Q & A format. Q 1: What does https stand for? A: https is the acronym of Hyper-Text Transmission Protocol Secure Version. The 's' is optional. With 's' present the messages transmitted are encrypted. Clearly, for banking etc purposes you ALWAYS want to see that 's' present. Q 2: But why did you call it a URI when everybody else calls is a URL? A: Ah - I thought you would never ask :-). The URL moniker is wrong. URL refers only to the part after the domain name (savage.net.au). So the URL is actually /misc/Digital.Security.Wiki.html. The structure is thus: URI = ProtocolName://DomainName/URL. Q 3: Can we ever force everyone to say - correctly - URI rather than URL? A: No. That is a lost cause. Sigh. Q 4: How does browsing on the internet work? A: The complexity is vast, beyond imagination, so here I will give you just a brief introduction. You usually use a program called a Browser, whose proper name is Web Client. Computer Operating Systems have various types of browsers, eg file browsers, but Browser has come to be the near-universal abbreviation of Web Client. And this Web Client talks to (exchanges messages with) a program whose proper name is Web Server. So we have a Client-Server relationship. Thus: Computer A runs an Operating System, which in turn runs dozens of programs, one of which is a Web Server. The latter initializes itself & then simply waits until someone using a Web Client sends a HTTP (Hyper-Text Transmission Protocol-based) Request from their computer (computer B) to the Web Server's computer. The Web Server responds by 'serving' up the requested web page as its Response, & then becomes quiescent, waiting for another incoming HTTP request, from computer B or from any other Web Client on any other computer. Q 5: What happens when you leave off the URL? A: Typing https://savage.net.au into your Web Client means there is no trailing /, so your Web Client will fabricate the /. Then the Web Server will see you have not typed in a file name, hence it will (most likely) automatically assume you meant index.html for the file name, & it will fabricate that as well. Thus https://savage.net.au becomes https://savage.net.au/index.html. Of course some Web Servers are configured to behave differently, but the end result is always going to be something similar to what I have explained. For instance they might react to seeing https://savage.net.au/ by running a program which creates a web page on-the-fly, rather than serving up a pre-existing file. And the contents of this fabricated web page will be read from a database. Q 6: And how do people make web pages pretty, fancy, complex etc? A:By using more than HTML (Hyper-Text Markup Language) in their web pages. For instance, my home page contains this line (at line 14 within index.html): Note: CSS stands for Cascading Style Sheets, so I can add 'style' to my web site. Note: The raw HTML etc of index.html is visible if you right-click on the page & choose 'View Page Source' from the drop-down menu. So for your Web Client to display my home page it must also download and process https://savage.net.au/assets/css/local/default.css. Note: It does this automatically. Using a similar inclusion mechanism, various other files containing almost anything (eg images) can be included in web pages you view, & each such file is a security risk in that criminals can include (in the downloaded file) programs which run automatically on your computer as soon as the are received & processed by your Web Client.