Internet Overview

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.

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.

• Underlined text, often in blue, acts as a hyperlink, allowing you to move to another Web location by clicking on the link. A hot spot, embedded into graphics, works in a similar way.

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.

• Some pages also contain active content, commonly provided via systems such as JavaScript or ActiveX. However, not all browsers fully support this technology.
• To search for words on the Internet you should separate each word by a space. However, if you want to search for text that contains a space you should enclose it all in quote marks.

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.

• Some mail users send messages containing HTML styled text, although not all e-mail applications accommodate this. Programs that support HTML may require you to reconnect to the Internet to see the images in the document, although styled text can be seen immediately.
• If you subscribe to an Internet mailing list you’ll receive lots of mail automatically. Indeed, if you’re not careful about remaining anonymous you may well fall victim to spam, the unsolicited bulk distribution of e-mail, often containing material of a dubious nature.
• Some ISPs impose a limit on the size of a file that can be attached to an e-mail message.

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.

• Online messaging shouldn’t be confused with the Short Messaging Service (SMS), as used on mobile phones, although you may be able to find software that links into the SMS system.

The following systems are in use:-

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.

• Newsgroups can be reached without special software by visiting the Google Groups Web site.

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.

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.

• Where communication is required without a conventional telephone at either end you must ensure that both parties have software that doesn’t require an ITSP.
• The modern standards for telephony are known as Voice over Internet Protocol (VoIP), and uses Session Initiation Protocol (SIP) or H.323. Some VoIP applications can also send speech messages via AIM to a SIP-compatible phone that has messaging enabled. In the United Kingdom you can use the BT Broadband Voice package, which is based on VoIP and can reduce the cost of calls by up to 25%.

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.

• You can speed up the backup process by compressing your files with an application such as DropStuff before you upload them to your Web space.
• You should encrypt your documents if they contain confidential information.

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.

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.

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.

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.

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

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

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:-

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:-

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:-

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:-

• Click here to see more TLD codes. When you’ve finished looking at the table simply click on your browser’s Back button to return to this page.

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