Key Terms
browser
cloud storage
domain
hosting service
HTML
hyperlinks
IP address
ISP
LAN
POP3 server
router
TCP/IP
web mail
world wide web (WWW)
If the computer is the most revolutionary machine ever made, one could argue that the Internet is the most revolutionary application of the computer. Actually the Internet is nothing more than a very large number of computers all talking to each other, but it is how this has changed us (as a society) that makes it revolutionary. The Internet was conceived by the Department of Defense way back in 1969 (ARPANET) as a strategy during combat. The idea was to link as many computers as possible so that communications would still be possible even if a large number of computers were destroyed. The idea was actually tested in Operation Desert Storm because Saddam Hussein used the same strategy, and it worked for him. Since many of these computers were housed in large universities, educators soon realized that this large network made for efficient communications between colleagues. The use of email was commonplace for a select few, many years before it was available to you and me.
In the late 1980's and early 1990's, people started hearing about this "information highway" which was making its way into society. It consisted of email, a text-based way of finding things called Gopher, and thousands of "bulletin boards" where people could post messages or hawk software. Milwaukee based Exec-PC was one of the largest in the world. With a squealing modem and a few bucks a month, you were "in". On a personal note, I was wondering just how useful this Internet could be. When comet Shoemaker-Levy 9 hit Jupiter in 1994, I was looking at a NASA photo I downloaded just hours after the impact. I was hooked.
Any computer that links to another computer is part of a network. It is quite easy to link the computers within your own home so they all share an Internet connection and/or files between computers. To make a local area network (LAN), all you need is an inexpensive router (hub) to link the individual computers. The individual computers can be linked by cables or with a wireless connection.
A typical home network (LAN)
To access computers outside your home, you need a gateway known as an ISP (Internet service provider). Many schools offer this as a free service to their students, or you can pay a monthly charge for a commercial provider (ATT, Comcast, CenturyLink, Time Warner, etc.). Homes connect to their ISP through phone lines (modem), DSL (Digital Subscriber Line), cable modem (high speed broadband), or even a satellite link. Businesses and universities usually connect with local area networks (LAN). Notebook / Laptop computers can access the Internet wirelessly through WiFi (hotspots), which became popular around 2000. Smart phones connect through their provider or WiFi. You can access the Internet on your Smart TV. Getting access to the Internet is getting easier and easier.
When you access the Internet, your computer becomes part of the Internet! One global network! That is, there is no central "Internet computers" that you tap into, ... just millions of computers all talking to each other. If you don't want people into your computer, you need to have blocking software (a firewall) and security software (virus protection) for privacy and protection. Most people use the Internet for email and to access to the WWW (World Wide Web).
Although no one individual owns or runs the Internet, there are organizations that establish standards for the Internet. For example, the Internet Engineering Task Force (IETF) establishes Internet protocols and the Internet Architectural Board (IAB) handles.... err ... architectural issues. Other groups who help set standards are the World Wide Web Consortium (W3C), InterNIC, and the Internet Society. These guys make the rules, but everyone plays the game.
Computers on the Internet need to know who everyone is. Similar to telephones, where every phone has a unique number, computers (also routers and network printers) have an identification number known as an IP address. Your computer has a static IP address if it never changes, but most home computers are assigned a new IP address each time they log on the Internet. This is known as a dynamic IP address. Since humans work with words and computers work with numbers, special computers (called DNS or Domain Name Servers) function like a telephone book, ...translating words like someone@somewhere.com or http://somecomputer.com/folder/file.htm to a specific computer holding information.
The Internet is really a network of networks. Within a local area network (LAN), a central server links individual computers using hubs in a variety of ways (using protocols like Ethernet, Token-Ring, WiFi, etc.). Networks need to send information to other networks. These links are called bridges and gateways. Since this can often involve great distances, devices called repeaters are used to amplify the signals along the way (which naturally weaken with distance).
Information moves from network to network in packets. That is, long data streams are broken into manageable bundles of about 1,500 characters. Information is appended to each bundle indicating the sequence (of each packet in the original message) and destination of the packet. Routers are used to transport the packets to their destination. Routers are like the traffic cops for information. They find the most direct route for the packet. That is, if Internet traffic is congested in one path, the router finds an alternate path. Along each step, routers talk to each other, ...confirming that a packet arrives intact at each step. Your original message may hop through several routers and each packet can take a different path. It is like taking a book, ripping out each page, and mailing them separately to a friend. Each page could travel a different path, but all pages eventually end up in the same mailbox. At the end, the packets are reassembled to form the original message. This system of moving data along the Internet is established by a protocol known as TCP/IP. TCP (Transmission Control Protocol) defines the rules for breaking up and recombining packets and IP (Internet Protocol) sets the standards for sending them.
Back in 1989, Tim Berners-Lee (link 7.7.a) developed the idea that computers can share information graphically using a protocol named HTML (Hypertext Markup Language). This is actually the software language standard for creating and reading web pages. Web pages are written in this code, identified by a URL - Uniform Resource Locator (for example http://www.google.com) and stored on severs all over the world. The page you are reading now is stored on one of our school's server. To see the HTML source code behind any web page you are viewing, click link 7.7.b for directions. It will look very cryptic. I've clipped the HTML code for the first sentence of this paragraph below:
<p align="left">
Back in 1989, Tim Berners-Lee (<a target="_blank" href="http://www.w3.org/People/Berners-Lee/">link
7.7.a</a>) developed the idea that computers can share information
graphically using a protocol named HTML (<b>H</b>yper<b>t</b>ext <b>M</b>arkup
<b>L</b>anguage).
One key component to Tim Berners-Lee's dream was the ability to link to other web pages with the click of the mouse. It is these hyperlinks that inspired the phrase "world wide web".
Sorry, I'm getting a bit ahead of myself. Part of Sir Tim's vision required software to read and translate the HTML code. That is, you needed a browser to make the code come alive. The first browser was Mosaic, but the developers of that program formed their own company -Netscape, and soon that software was on most computers. Bill Gates bullied his way into the browser market, and after many lawsuits, Microsoft's Internet Explorer (IE) won the battle of the browsers. However, other competitors - Firefox (Mozilla), Safari (Apple), and Google Chrome, have entered the ring. The browser runs from your local computer (called the client) and interacts with a server provided by your ISP host (ATT, Comcast, CenturyLink, Time Warner, etc.). When you enter (or click a link to) a specific web page (like http://www.google.com), a request is sent to the server holding the web page. The HTML code is sent to your ISP's server and from there, to your browser. The browser then interprets the code and displays the page. HTML code has gotten fancier and browsers need to be updated to handle new code and advanced features. You can enhance the capabilities of your browser by adding "plug-ins" like Java and Macromedia Flash. Also, it helps to keep all your software up to date with the latest versions
Creative web sites are popping up all the time which offers interesting and new ways to interact on the Internet. The ability to communicate at the speed of light has led to a revolution in the way we interact with computers (or other people with computers). Each new idea comes from a developer's mind and becomes reality through software. This software boom allows us to:
These possibilities change the ways we interact with other people, how we work, play, vote, learn, and how we live our lives. Has this software revolution brought on a cultural revolution? My answer is a big fat - YES! .... sometimes not always for the good. If interested, read my personal opinion.
Internet of Things
The internet is not just computers but all kinds of devices to (hopefully) improve our lives. A "smart house" can have gizmos that can remotely control lights, refrigerators, security systems, garage doors, thermostats, ... just about anything. All these wireless devices connect via WiFi through your router. But a word of caution is in order here. Hackers look for not-so-smart people with lots of smart devices. The key is to always change the manufacture's default ID and password (including your router). That's exactly what someone exploited on October, 21, 2016 and most people didn't even know they had been hacked. Once one device is hacked, it exposes all the devices on your network to invasions. Even if you take every possible precaution in this regard, the manufacturers of these gizmos may have overlooked some security hole. Simply stated, the more smart devices you have in your home, the more vulnerable your network is to invasion.
Let's bring this back down and look at something most people do every day - read email. How an email gets to you is incredibly easy to understand. First, you need an email hosting service. Your email host is identified by the characters after the @ symbol in your email address. Examples are @matc.edu or @gmail.com and are known as the domain. The hosting service assigns you a unique email address which takes this form: me@someplace.com ... the characters to the left of the @ symbol identify you in their system (called the ID). Each host has a computer which acts as your incoming email server, a place that will collect your incoming emails and hold them until you are ready to read them. The host uses a different computer to handle your outgoing email (called the SMTP server). I subscribe to Time Warner Roadrunner as my ISP, so my incoming (POP3) server name is pop-server.wi.rr.com and my outgoing server name is smtp-server.wi.rr.com.
When you send out an email, the outgoing (SMTP) server handles it as a simple text file (keyboard characters only). Special characters are used to separate the components of the email (to:, from:, subject:, body, etc.). If you have attachments to your email (pictures, for example) a special program (called uuencode) takes the binary data and converts it to text characters, which gets appended to the file.
How uuencode coverts binary data to text characters
This string of text characters is sent out to the recipient's incoming server. As new emails come into the recipient's incoming server, they are appended to this text file (again with special characters as identifiers and spacers). If email is not checked often, this file gets longer and longer. When the recipient logs into the host, the server finds this file, and a program breaks it back down to individual messages (and also converts the attachments back to binary data). What they see is a stream of individual messages ... pictures and all. Email comes in two protocols:
Web mail can be read from any computer with an Internet connection. This is because the actual message resides on some remote server, and when you read it, it stays there. Your access computer only lets you view it, but does not download it (put it on your hard drive). However, the remote server will give you that option if you request it. Popular examples of web mail clients are Hotmail, Gmail, and Yahoo mail.
POP3 / IMAP email requires specific software (like MS Outlook) loaded on the computer before accessing it. When you log to the server, it moves the messages from their incoming mail server to your computer (downloads it to your hard drive). When sending an email, your message is moved (uploaded) from your computer to your email hosts outgoing mail server, and from there it goes to the recipient's incoming server.
The Cloud
In the early days of the Internet there was only one place to store things - locally. Your computer had a hard drive and likely a CD or DVD burner. You would back up your data locally as well. As high speed Internet became commonplace, so too became the use of remote sites to store your data. The Cloud is nothing more than someone else's computer. Now data centers (some the size of 10 football fields) have sprung up all over the globe. They number in the millions in just the US alone and consume almost 2% of the electricity produced in the country. You will likely never see them because they are generally built where real estate is cheap. So what kinds of things do these centers hold?
©2001, 2004, 2007, 2009, 2016, 2018 by Jim Mihal - All rights reserved
No portion may be distributed without the expressed written permission of the author