Internet Overview

The Internet provides access to a world-wide network of computers with over 50 million users. The word ‘Internet’ comes from the phrase international network of computers, although it’s also derived from Internetworking Protocol (IP), the software mechanism that runs the system. Access to the Internet is provided via an Internet server computer. This is run by your chosen Internet service provider (ISP), sometimes known as an Internet access provider (IAP).

Your ISP may charge a setup fee as well as a monthly subscription, to which you must add the cost of telephone calls. Although the latter are normally charged at local or ‘low-call’ rates the cost soon builds up over time. Those ISPs in the United Kingdom that don’t charge fees normally take a ‘cut’ of the call charges, although they may also increase their profits by advertising on the Internet.

A server computer using Internet protocols can also be used over a local network, for example within the company in which you work. This kind of system is commonly known as an Intranet.

A Short History

The Internet began with the Advanced Research Projects Agency Network (ARPANET), created in 1969 by the American Department of Defense to link four cities. By 1972 there were 37 computers operating on the system and the National Center for Supercomputing Applications (NCSA) had developed the Telnet log-on application. The following year saw the introduction of international connections to ARPANET and the development of File Transfer Protocol (FTP).

By 1974 the Internet proper was in use, part of ARPANET splitting away in 1983 to form Military Net (MILNET). At this time other networks appeared, including Usenet for newsgroups, Unix-to-Unix Copy Protocol (UUCP), the transport mechanism for Usenet, as well as Bitnet, DECNet and FidoNet. In the United Kingdom the Joint Academic Network (Janet) was widely used by colleges and universities.

In 1982 the Internet’s original NCP/IP protocols were replaced by TCP/IP and in the following year the Domain Name System (DNS) appeared. In 1986 the National Science Foundation established NSFNet, forming the backbone of the modern Internet.

In 1990 the British programmer Tim Berners-Lee devised hypertext and HTML whilst at CERN in Switzerland, so creating the World Wide Web. In the 1990s the older networks such as Bitnet, DECNet, FidoNet and Usenet developed ‘gateways’ into the new system, tuning them into virtual networks that could be reached via the Internet.. By 1994 Web browsers such as Mosaic and Netscape had appeared and one year later Microsoft entered the fray with Internet Explorer.

  Internet Services

The various Internet services, each with a specific protocol, are described below. In Mac OS X the default applications for the World Wide Web and e-mail are determined by the Preferences settings in Apple’s Safari and Mail applications respectively. The defaults for these and other protocols can also be adjusted through a third-party preference pane called More Internet (Monkeyfood.com). In the Classic Mac OS you can set the applications in the Internet control panel.

  World Wide Web (WWW)

The ‘Web’, often confused with the Internet itself, uses the mouse-driven Hypertext Transfer Protocol (HTTP). Each website consists of several Web pages containing text as well as GIF, JPEG or PNG graphics that can be viewed by means of a Web browser application.

Each Web page consists of a special text document that contains Hypertext Markup Language (HTML) instructions. Such a document can be created in an HTML editor or in a suitable application that allows the result to be converted into an HTML file using an HTML translator.

Web Applications: iCab (iCab Company), Internet Explorer (Microsoft ), Netscape (Netscape Communications Corp), Opera (Opera Software AS), Safari (Apple).

  Electronic Mail (E-mail)

Electronic mail lets you send text messages, as well as attached files to other Internet users. The most common protocols are Simple Mail Transfer Protocol (SMTP) and Post Office Protocol 3 (POP3), although Internet Mail Access Protocol (IMAP) is becoming more popular, whilst the older UNIX-to-UNIX Copy Protocol (UUCP) is rarely encountered. POP3 moves mail from a server to your computer whilst IMAP, frequently favoured by large organisations, lets you leave mail on your server so that it can be read by any other computer.

E-mail Applications: Emailer, Entourage (Microsoft), Eudora, Mail (Apple), Netscape (Netscape Communications Corp), Outlook Express (Microsoft).

  Online Messaging

Also known as instant messaging (IM), this is similar to e-mail, except that each message is sent immediately. If the recipient isn’t available it appears whenever they connect to the Internet. Some systems, known as direct chat or live chat, actually show the message as it’s being typed.

The following systems are in use:-

America Online Instant Messenger (AIM)

This is supported by the AOL (America Online) application, iChatAV, iChat (Apple) and some versions of Netscape (Netscape Communications Corp). The latest variation of iChat, known as iChatAV, also allows video conferencing and employs CDMA technology, as used in mobile phones, to provide an excellent sound quality. It also works with Apple’s iSight Web camera, which connects to your computer via FireWire and has a useful built-in microphone. However, to use this kind of camera you’ll need a broadband Internet connection.

ICQ (I Seek You)

ICQ is provided for by a free time-limited application. It’s also supported by Yahoo’s Yahoo Messenger application, the latter of which also accommodates AIM.

Internet Relay Chat (IRC)

This, the most complex system, is supported by a shareware application called Ircle. It provides live chatting between multiple users, overlapping with newsgroups (see below) and the Multi-User Dimension (MUD).

.NET Messenger Service

This proprietary mechanism is supported by the MSN Messenger application in Windows and the Mac OS. It requires a .NET Passport profile and a password containing at least six characters.

Messaging Applications: AIM, GlobalChat, ICQ, iChat, iChatAV, Ircle, MSN Messenger, Yahoo Messenger.

  Newsgroups (Usenet)

Access to a newsgroup, also known as a bulletin board service (BBS) is provided via a mechanism known as Network News Transfer Protocol (NNTP) or Usenet. At the time of writing, there are over 50,000 public newsgroups, to which contributors can upload their material. Others can read this information or download the data as required.

When you run a newsgroup application it lists all the available newsgroups, a process that can take ten minutes or more. You can then look through the lists and click on an interesting topic.

Newsgroup Applications: Entourage (Microsoft), NewsWatcher, Nuntius, Outlook Express (Microsoft).

Real-Time Streaming

Some Internet locations provide real-time audio or video material, either directly or via a website.

Audio streaming is often used to provide an Internet radio station, frequently conveying the same material as a real radio station of the same name. However, unlike a radio transmitter, whose coverage is limited to a local area, an Internet station can be heard worldwide. The popular iTunes application for the Mac OS employs Kerbango radio services, allowing you to receive radio broadcasts that are based on MP3 streaming. Unfortunately, far more radio stations operate with the RealAudio format, now known as RealMedia, requiring you to use the free RealPlayer application.

Video streaming may also requires different software, usually QuickTime Player or RealPlayer.

Streaming Applications: iTunes (Apple), QuickTime Player (Apple), RealPlayer (Real).

Really Simple Syndication (RSS)

An RSS application lets you browse through ‘headlines’, which you click on to open in your Web browser. Although a special RSS application is often used, the version of Safari supplied with Mac OS X 10.4 also operates as a headline browser.

  Telephony

This allows speech to be conveyed as digital data. Since most calls to the Internet are charged at a local rate this is far cheaper than an ordinary telephone, although quality and reliability can be less than perfect. Internet telephony requires special software, although some applications won’t work on Mac G3 computers that can only sample sounds at 44.1 kHz.

To call others who aren’t on the Internet you’ll also need to register with an Internet telephone service provider (ITSP), a ‘virtual’ telephone company that provides a gateway between the Internet and the normal telephone system.

  Internet Backup

Instead of using a disk drive, you can backup your data onto Web space provided by your ISP. However, you should remember that this process can take a considerable time, thereby adding to your phone bill.

Backup Service: .mac (Apple).

File Transfer Protocol (FTP)

This system, originally employed on Unix computers, lets you upload and download material to and from a remote site. Most users only use this when setting up a website on the server provided by their ISP. Fortunately, most applications used for the design of Web pages also accommodate FTP.

FTP Applications: Interarchy/Anarchie, Fetch, Internet Explorer (Microsoft), Transmit (Panic), TurboGopher.

Telnet

This lets you log onto a remote machine, usually by emulating a VT102 terminal. The term ‘Telnet’ is derived from the original Unix utility, as used for dialling-up Internet hosts.

Telnet Applications: NCSA Telnet, Versaterm Link.

  Special Services

Other services are available. For example, MSN Messenger, which works via the Office Notifications application in Microsoft’s Office package, lets you receive .NET alerts. This service provides live information from the MSN website.

  Hardware and Providers

Most users get onto the Internet via the Public Switched Telephone Network (PSTN), employing a dial-up telephone line and a modem. For best results a 56 kbit/s modem should be used, although 28.8 kbit/s device may be acceptable to some users. For faster performance you can use a more expensive Integrated Digital Services Network (ISDN) or Advanced Digital Subscriber Line (ADSL) connection, although these need special wiring and hardware to match.

Service Providers

Having obtained the necessary hardware and basic software you’ll need to contact an Internet service provider (ISP). Alternatively, you can reach the Internet using an online service such as America Online (AOL) or CompuServe. Although these are easy to set up and provide additional features, they’re less flexible than a standard provider and running costs may be higher.

Subscribing to an ISP

In theory, establishing a connection isn’t difficult.You simply subscribe to an ISP, often by using special software, and the provider sends you the information to set up your machine’s software. In practice, there’s often confusion, either as a result of variations in terminology, sometimes due to differences in computer platforms, or a lack of understanding by the provider or the customer.

The ISP must give you an Internet address, such as bloggs.supernet.co.uk, a telephone number for the dial-up connection, an optional IP address of the form 56.89.3.78, and other data necessary for setting up the connection. Once you’ve entered the relevant information into the windows of the appropriate software you should be able to launch your Internet applications.

If you require your own domain name, such as bloggsandson.co.uk you’ll need to register it with the body that regulates domain names in your country: in the United Kingdom it’s Nominet. They should ensure that only you can use your chosen domain name, although this has been known to go wrong. The DNS server site, which converts your name into an IP address, may be run by your ISP or another company with whom you must register. Unfortunately, things can get rather complicated if you already have a domain name assigned to you and then decide to change your ISP.

Uniform Resource Locators

Each Internet service employs a particular protocol, which defines the rules of engagement for computers conveying the information. This protocol is shown at the beginning of the Uniform Resource Locator (URL) for each site. For example, the URL for a website is frequently in the form of http://www.bloggs.com, indicating that this is an HTTP connection.

URLs can contain both uppercase and lowercase letters, although it doesn’t usually matter which case is used for any of the letters. In all instances, however, they can only contain standard ASCII characters, corresponding to those that you can actually see on your computer keyboard. Note that spaces or other control codes are not permitted.

URLs and Domain Names

Some fictitious URLs are shown below. In all of these, the part before the colon gives the protocol whilst the rest makes up the Domain Name System (DNS) address or domain name.

Example URLKind
afp://24.48.72.96/MyDisk/AAppleShare Server
at://fredAppleTalk Workstation
ftp://ftp.bloggs.comFTP
http://www.bloggs.comWorld Wide Web
https://www.bloggs.comWorld Wide Web (secure site)
mailto:fred@bloggs.comE-mail
nntp://jones.comNews via NNTP server
news://bloggs.comNews
telnet://bloggs.ukTelnet

Rather more obscure URLs are required for Chat and Finger services, as shown here:-

URL FormatKind
chat://#channel@server.domainChat
finger://userID@server.domainFinger

Where more than one computer exists in an area, the domain can be split into two parts, as in:-

mailto:fred@.central.bloggs.com

The middle part, in this instance central, is known as a sub domain. This is the name of the host or server computer that handles data exclusively for ‘fred’ and his colleagues. The rightmost part gives the host’s network area or main domain name, in this case bloggs.com.

Directories and Files

URLs can also point your Internet application to a file within a specified directory, where each directory is the Internet equivalent of a desktop folder. For example, the URL:-

http://www.bloggs.com/bloggs_info/new_products/televisions.html

takes your Internet application to the file televisions.html which is contained in the folder new_products which itself is in a ‘topmost’ folder called bloggs_info. The domains in such a URL can be considered as a tree, where the largest domain appears at the very top and the required file appears at the bottom, as shown in the following diagram:-

URLs can also point to a file on a ‘local’ hard disk drive, as in:-

file:///Macintosh%20HD/System%20Folder/Help/Help%20Center

This address directs your Web browser to the Help Center file, which is normally present in Classic Mac OS 8.x or higher. This kind of address is distinguished from a ‘remote’ URL by its prefix of three slashes. In addition, each space character in the filenames is replaced by %20, which simply means ‘hexadecimal 20’, the ASCII code number for a space.

Suffixes and Top-Level Domains

Common URL suffixes, often used in combinations, include the following:-

SuffixKind of Site
.acAcademic body
.bizBusiness organisation
.coCommercial business (not USA)
.comCommercial business (USA or worldwide)
.coopCo-operative organisation
.eduEducational establishment
.govCivilian government
.infoInformation site
.milMilitary government
.museumMuseum
.nameNamed individual
.netNetwork gateway
.orgNon-commercial organisation
.proProfessional body

In the United States most domain names simply end in one of the above suffixes. However, in other countries an extra code is often required to identify the region, which is commonly known as the top level domain (TLD). Here are a few examples:-

TLDRegion
.euEuropean Union
.frFrance
.itItaly
.jpJapan
.krKorea
.suEx-Soviet Union state
.ukUnited Kingdom
.usUSA (Other sites)

The United Kingdom now uses various codes, including the following:-

SuffixKind of Site
co.ukCommercial business
gb.comCommercial business (Great Britain)
gb.netNetwork gateway (Great Britain)
ltd.co.ukCommercial business (limited company)
me.ukNamed individual
org.ukNon-commercial organisation
uk.comCommercial business
uk.netNetwork gateway

©Ray White 2004.