How the iPad works

Dig into the technologies underlying today's hottest gadget

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Lingle explains how a lithium-polymer battery works in even more basic terms: There is a positive side and negative side, and electrons jump from one side to the other to form a charge. When the chemical is excited by electrical power, the electrons flow through this circuit -- because that is the shortest and easiest path to take -- and eventually the polymer chemical won't be able to make this jump anymore and will stop charging.

According to Lingle, the polymer chemical material in the iPad battery is likely either polyethylene oxide or polyethylene acrylonitrile.

Embedded Web audio and video

Apple CEO Steve Jobs has stated his dislike of Adobe Flash, a multimedia platform that's used widely across the Web, on more than one occasion. The iPhone doesn't support Flash, and neither does the iPad. Instead, the Safari browser found in the new device supports HTML 5, the next iteration (still under development) of the HTML standard.

Like other multimedia platforms, such as Microsoft Silverlight, Flash requires that you install a third-party plug-in to view videos and other rich content on the Web. HTML 5, on the other hand, supports embedded video and audio so you can play them right in the browser without installing a plug-in.

David Stude, a software engineer at PDT, says HTML 5 also supports vector graphics that can scale and shift on the screen during Web browsing, similar to how a table in Microsoft Word can change size depending on the zoom level. Stude says his company has done prototyping for embedded devices -- gadgets like the Chumby or Wiki Reader that act like a computer with an operating system but are self-contained -- with HTML 5 instead of Flash because it is easier to set up software routines.

Flash and Silverlight require proprietary scripting languages, says Stude, but HTML 5 is a one-stop shop for programming rich content into a Web page that anyone can use. While HTML 5 is still years away from being finalized, as an emerging standard it will help developers create apps for all devices that support it, regardless of whether they have a proprietary add-on. In addition to Safari, the most recent versions of Firefox, Opera and Google Chrome provide some support for HTML 5 features, and Microsoft has promised that Internet Explorer 9 will also adhere to HTML 5 standards.

Of course, some view the lack of Flash support as a serious detriment. The majority of interactive elements on the Web today are built in Flash, which means they won't work on the iPad. But Jobs and others are confident that as HTML 5 matures, more Web developers will create apps using HTML 5. In the meantime, Apple is providing a short list of big-name HTML 5-friendly Web sites that work perfectly on the iPad.

Apple likes to use the word "magical" when describing the iPad, and it may feel that way when you're using it. But what seems like magic can be explained with hard science after all.

John Brandon is a veteran of the computing industry, having worked as an IT manager for 10 years and a tech journalist for another 10. He has written more than 2,500 feature articles and is a regular contributor to Computerworld.

Copyright © 2010 IDG Communications, Inc.

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