The History and Technology Behind Radio Podcasting

The history of the Podcast goes back a relatively short ways considering its use of newer technologies and ideas. The true beginning of the term "Radio Podcast" as it is used today would have to be February 12, 2004. Bill Hammersley is a British journalist and in one of his articles in The Guardian (A British Newspaper) he referred to the boom of amateur radio and portable audio blogging in many ways, one term he used while describing and examining current portable audio technologies was, "Podcasting."

While this marks the first documented appearance of the word, "Podcast" it does not mark the beginnings of Podcast technology. After all, it is merely a word to describe a sequence of methods used to record, easily distribute and mobilize audio media. In order to delve deeper into the history of Podcasting, further explanation of the technology behind it is needed.

The Technology

Receiving audio media through an automatic tool requires what is now known as a feed reader or aggregator. Distributing media to these readers requires XML files containing the information to read from. These XML formatted files originally contained what is now called RSS (really simple syndication.) This automation of transfer is done through the use of the internet and identified using a uniform resource identifier, most commonly a URL and/or URI. This information is placed inside the feed, usually and initially as an RSS file. Using the uniform resource identifier and internet availability the feed is put online and individuals can obtain (subscribe to) the feed and read its contents through their feed reader.

The technology behind the RSS documents exists as an XML document. XML stands for Extensible Markup Language and is the formatted code that is placed inside the RSS document. While the language inside an RSS document is written in XML, the file extension of the RSS file is .rss. The information stored inside an RSS file can include many different things including title, description, dates, file URL, file type, etc. The RSS file must contain the location of your audio file in order to play correctly. The location of your audio file called out inside the XML document is in direct relation to the entire website, weblog, etc.. For example, if your audio files are in a sub directory folder labeled, "podcastfiles," your website address is: http:///www.mywebsiteaddress, and the audio clip is called: myaudioclip.mp3, the location of that clip inside the RSS document would look like this:

http://www.mywebsiteaddress.com/podcastfiles/myaudioclip.mp3

That way the XML document knows where to find that file in order to play it back for your subscribers in their feed reader.

The feed can automatically be updated with the use of Push Technology. The concept of each feed being updated automatically by the publisher and "pushed" to the subscriber is the basis of this idea and is what really distinguishes the idea of feed readers and RSS documents. For example, you can receive news updates, weather updates and, of course, the latest entries of you favorite radio podcast right through your feed reader, without doing anything but receiving the latest "pushed" information.

It is important to note that the technology behind XML, RSS and feed readers is not exclusive to Podcasting and remains consistent with the methods of news article feeds, blog feeds, education feeds, etc.