Introduction to How the Amazon Kindle Works

In 2007, the Internet commerce company Amazon introduced a $399 (now priced from $79 up to $199, depending on the ad-supported model) electronic book (e-book) reader called the Kindle. The Kindle wasn't the first dedicated e-book reader device, but it didn't really have much competition -- there wasn't a huge demand in the market for e-book readers before the Kindle's launch.

Amazon has two distinct advantages over earlier e-book manufacturers. The first is that the company designed the Kindle to interface seamlessly with Amazon's online store. Amazon.com hosts hundreds of thousands of titles, many of which you can order in electronic format. Because the Kindle is wireless, you can access the store without connecting the device to a computer. You can buy a book or subscribe to an electronic version of a newspaper on Amazon and download it directly to the Kindle. The second advantage is that Amazon has a large customer base. Both of these factors give the Kindle a leg up on the competition.

Why would you want to use an e-book reader in the first place? One reason is that a single e-book reader can hold many titles. The $79 Kindle, Amazon's base model, can hold up to 1,400 titles (books, newspapers, magazines and blogs) in its memory [source: Amazon]. The newer models also offer WiFi connectivity. The original Kindle had a port that allowed users to save titles to a memory card, extending the device's capacity, which appeals to people who like the idea of having an electronic library that takes up very little physical space.

­The Kindle's memory capacity also makes it very convenient for travelers. With a Kindle, you don't have to worry about packing heavy books in your luggage to keep you occupied for your whole trip. A single Kindle can hold more than enough titles to tide you over. And if you decide you want something completely different midway through your travels (as long as you're traveling in the United States or a country in which Amazon offers service for its international Kindle), you can always use the Kindle to access Amazon's store and buy a new book.

The Kindle also has several functions that you may find helpful while reading. You can bookmark a page, highlight a selection of text or even type notes as you read. With these features, the Kindle has the potential to replace hardcopy textbooks in the future, something many students would probably welcome. While they would no longer be able to sell a used copy of a textbook at the end of a term, they wouldn't have to tote around a backpack filled with hefty books.

Next, we'll take a closer look at the Kindle.

Amazon Kindle Layout

­The original Kindle has an off-white plastic casing and an asymmetric, beveled shape, like a closed three-ring binder. It has a rubberized back that makes it easier for users to hold the device. It's 7.5 inches (19 centimeters) long and 5.3 inches (13.5 centimeters) wide. It's only 0.7 inches (1.8 centimeters) thick and weighs a mere 10.3 ounces.

Amazon has changed the design of the Kindle a few times since its introduction. The third-generation device, also known as the Kindle Keyboard, is less angular than the original model. The Keyboard is just as tall as the first Kindle but is less angular a little narrower at 4.8 inches (12.2 centimeters) wide. The WiFi Kindle Keyboard is 0.3 inches (8.6 millimeters) and weighs 8.5 ounces (241 grams). The Kindle DX is the big brother of the series. It's 10.4 inches (26.4 centimeters) long, 7.2 inches (18.3 centimeters) wide and 0.4 inches (9.7 millimeters) thick. It weighs 18.9 ounces (535.8 grams). The 3G models of the Kindle Keyboard and Kindle DX are just a touch thicker and heavier than their WiFi cousins.

In September 2011, Amazon unveiled three new Kindle models with E Ink electronic ink displays and a tablet called the Kindle Fire. The first new Kindle model, which is now the base model for Amazon, uses a five-way controller and doesn't have a keyboard. It's the smallest Kindle yet, measuring in at 6.5 inches (17.3 centimeters) long and 4.5 inches (11.4 centimeters) wide and weighs 6 ounces (170.1 grams). The two new Kindle Touch models -- one a WiFi only and the other a 3G and WiFi device -- have touch-screen interfaces and very few physical controls. They are a little larger than the basic Kindle, measuring at 6.8 inches long and 4.7 inches wide.

The central feature on all the Kindle models, with the exception of the Kindle Fire, is its electronic paper screen. The screens on all Kindle models except the DX and Fire measure 6 inches (15.2 centimeters) along the diagonal and have a resolution of 167 pixels per inch (PPI) [source: Amazon]. The screen can display images in 16 levels of gray. Unlike LCD screens, the Kindle's screen isn't backlit. That means you'll need a reading light if you want to skim a novel in a setting with little ambient light.

Features of the Kindle Keyboard

On either side of the Kindle Keyboard's screen you'll find two large buttons for "next page" and "previous page." The buttons have been completely redesigned since the first Kindle was released; some reviewers commented that the "back" and "previous page" buttons on the original Kindle sometimes function identically and at other times they do different things, which can cause confusion. Several critics have also pointed out that the placement of the buttons makes it easy for users to accidentally turn a page just by picking up the Kindle.

Beneath the screen on the original Kindle, you'll find a scroll wheel, a full keypad and an array of function buttons. The scroll wheel acts as a navigation interface -- like a mouse -- allowing the user to select options or specific lines of text. Pressing down on the wheel is like clicking a button on the mouse -- it lets you activate options. Newer Kindles replace the scroll wheel with a direction pad for navigation. The keypad allows you to or use the search feature or type notes while reading text. Home, Back and Menu buttons help you navigate through books and use the built-in Web browser.

On the base of the Kindle you'll find a headphone jack (the Kindle can play MP3 files), a USB port and a power adapter plug. You'll also find a pair of volume buttons. The power button is on the back of the Kindle along with a switch that activates the Kindle's wireless receiver. Underneath the removable rubberized pad is a slot that can accept a standard SD flash memory card. You'll also find the Kindle's removable battery pack there. Amazon removed the option to add memory or replace the battery on the Kindle 2 and Kindle DX. For the third-generation Kindle readers, the power switch was moved to the base of the device, along with all the other ports [source: Perenson].

The Kindle comes with a USB cable and a power adapter. The original Kindle also came with a protective book cover, which has a padded section that protects the screen and an elastic band that holds it closed. Amazon also has a selection of accessories for the Kindle, including leather covers and adapters for non-U.S. electrical systems.

Next, we'll take a closer look at the latest Kindles to hit the virtual shelves at Amazon.

Look Ma, (Almost) No Buttons!

The 2011 redesign of the Kindle line was dramatic. Many of the controls found on the earlier models of the Kindle disappeared. The basic Kindle replaced the keyboard and page controls with four buttons and a five-way controller. The touch-screen Kindles have two buttons -- one to turn the device on or off and a home button that returns you to the main menu.

The basic $79 Kindle doesn't support audio -- there's no speaker or headphone jack. To page through a book, you use the five-way controller. To type in notes or to browse blogs, you can pull up a virtual keyboard and enter keystrokes using the five-way controller. If that seems cumbersome or time-consuming, you can opt for a Keyboard Kindle or get one of the Kindle Touch models.

With the Kindle Touch devices, all your navigation, with the exception of the Home button, uses the touch-screen interface. Once in a book, tapping the right side of the screen advances the page. Tapping the leftmost edge of the screen pages back. You can also use swipe gestures to page forward or backward. A virtual keyboard allows you to type notes and browse.

Unlike the basic Kindle, the Kindle Touch models support audio. The Kindle Touch devices have rear-mounted speakers and a 3.5-millimeter audio jack.

The Kindle Fire is more of a tablet than a traditional e-reader. In fact, it bears a striking resemblance to the Blackberry Playbook. Like the Kindle Touch models, the Fire has a touch-screen user interface. But it doesn't feature an E Ink display. Instead, it has an in-plane switching (IPS), liquid crystal display (LCD). It features a special browser developed by Amazon called Silk. Underneath all the flash of the device is a heavily modified version of the Android operating system.

Now let's take a look at what makes the Kindle work.

Inside the Amazon Kindle

At its most basic level, the Kindle is just a specialized portable computer. It has many of the bits and pieces you'd expect to find in any computing system. It also has a couple of elements that set it apart from your average computer.

Most of the Kindle's components attach directly to a circuit board. The circuit board acts as the foundation for electronic circuits in the Kindle. Most of the components are inseparable from the board. The various chips on the board are microcontrollers for the keyboard, scroll wheel, touch-screen interface, five-way controller or joystick, USB port and other interfaces.

The Kindle draws its power from a rechargeable lithium-polymer battery. With the original Kindle, you can access the battery without taking the case apart. The rubberized grip on the back of the Kindle covers up the battery. According to Amazon, the battery will provide power to the original Kindle for up to a week without the need for recharging as long as the wireless function is switched off. The Kindle 2 and Kindle DX doubled the battery life to two weeks with the WiFi feature turned off (one week with it on). Amazon made the battery accessible on the original Kindle so that users can replace the battery if it fails. That feature isn't available on the later Kindle models.

Later versions of the Kindle pushed battery life even further. Amazon claims that the basic Kindle's battery will last one month with the WiFi turned off. The Kindle Touch and Kindle Keyboard models can last up to two months. The current Kindle DX is a 3G and WiFi model with three weeks' worth of battery life. The Kindle Fire, Amazon's tablet, is the odd man out -- it has an eight-hour battery life.

All versions of the Kindle -- with the exception of the Kindle Fire -- use a Linux-based operating system. According to hardware hacker Igor Skochinsky, it uses the Das U-Boot bootloader to initialize its OS. Skochinsky experimented with a Kindle and discovered several interesting commands, shortcuts and hidden applications within the Kindle's OS. For example, he discovered that if you press the Alt key, Shift key and M key while in the Home menu, the original Kindle will open up a game of Minesweeper [source: Skochinsky].

The Kindle Fire uses a modified version of the Android operating system. Android comes from Google and is a popular operating system in various smartphones and tablets. However, Amazon's version of the operating system doesn't resemble other versions of Android on the surface. You'll only notice the similarities if you're taking a hard look at the source code.

Beneath the circuit board on most Kindle models you'll find the Kindle's electronic paper screen. We'll take a closer look at this screen in the next section.

The E-book Reader Display

One complaint some people had about early e-book readers was that they found it difficult to read words on an LCD display. Some users complained that longer reading sessions put too much strain on their eyes. Amazon's solution to this problem was to use electronic ink technology. The Kindle's electronic ink screen looks more like paper than an LCD screen. It reflects light in much the same way that paper does. The screen lacks a backlight, so you'll need an external light source in order to read anything.

A company called E Ink in Cambridge, Mass., developed the technology the Kindle relies upon to display text and images. Rather than use the liquid crystals you'd find in an LCD or the ionized gas you'd find in a plasma display, electronic ink actually uses millions of microcapsules, only a few microns wide. Each microcapsule contains a clear fluid and thousands of white and black particles. The white particles carry a positive magnetic charge and the black particles have a negative charge.

It's these positively and negatively charged particles inside the microcapsules that make electronic ink displays possible. An array of thousands of tiny electrodes lies beneath the electronic ink display. When an electrode emits a negative charge, it repels the negatively charged black balls, pushing them to the top of the microcapsule. At the same time, the negative charge attracts the positively charged white particles to the bottom of the microcapsule. When the electrode emits a positive charge, the white and black particles switch places and the screen appears to be blank.

­Working together, thousands of electrodes and millions of microcapsules generate the text and images you can see on an electronic ink display. Through precise charges the Kindle can display a range of grays to provide shading in images. You can even adjust the Kindle's font settings to display text in a larger or smaller font size.

The Kindle uses less energy to generate a page view than a comparable LCD or plasma screen. The company's Web site states that the Kindle pulls power from its battery only during the initial page generation. It doesn't require more power until the user changes the page view. Because of this feature, the Kindle's battery can provide power for up to two months on a single charge (assuming the user doesn't have the wireless feature turned on).

The electronic ink display is one of the Amazon Kindle's top selling points. Another is the way it interfaces with Amazon's inventory of electronic books. We'll look into that more in the next section.

Amazon's E-book Store

To get the most out of your Amazon Kindle, you'll need to create an account with Amazon.com. It's a free process -- all you'll need is a valid e-mail address. Once you have an account, you can register your Kindle with Amazon. This gives you access to the Kindle Store through Amazon's wireless network, called Whispernet.

The Amazon Kindle's  modem gives you wireless access to an electronic store that includes more than 1 million books, newspapers and magazines [source: Amazon]. Amazon provides the wireless service for free -- you won't have to pay a subscription to access it. The Kindle allows you to buy books directly from the device. Alternately, you can browse books in the Kindle store using your computer's Web browser and purchase them from your computer. Amazon will send the electronic books directly to your device. You can also browse several blogs online.

You don't need to own a computer to use the Kindle. That's one feature that sets Kindle apart from some of its competitors. You don't have to sync the Kindle to another machine to transfer files. You can browse, sample, purchase and download titles from the Kindle itself.

The files you access ­with a Kindle are in a proprietary format with the extension AZW. The AZW files include digital rights management (DRM) that prevents you from sharing your files with other users. The Kindle can handle Most versions of the Kindle can handle Audible files (.aa) and MP3 files, two popular formats for audio books (the basic $79 Kindle is the one exception). Amazon also can convert several other types of files into the AZW format so that the Kindle can read them. These file types include:

• Text (.txt) files
• Unprotected MOBI files (.mobi o­r .prc)
• Word documents (.doc)
• HTML files
• Image files, including JPEG, GIF, BMP and PNG formats
• PDF files

Each Kindle has a unique e-mail address. You can send compatible files to your Kindle by e-mailing them directly to the device. Amazon charges $0.10 for each file. If you want to avoid the fee, you can e-mail the files to a special address at the free.kindle.com domain for free conversion. Amazon will convert the files and send them to the e-mail address associated with your Amazon account. To transfer files from your Amazon account to your Kindle, you'll need to connect the device to a computer using the USB cable. This is one of the few times you'll have to connect your device to another machine.

Every purchase you make from Amazon goes into a special folder called Your Media Library. Amazon uses a ­cloud storage model where the file lives on one of Amazon's computer servers. That means even if you delete a book from your Kindle to conserve space, the record of your purchase will still exist on Amazon's servers. You can download the book again to your Kindle for no additional charge.

Popularity of the Kindle

Upon its debut, the Amazon Kindle cost $399. While some critics said the nearly $400 price tag was too high, the demand for the Kindle soon depleted Amazon's stock of the device. Amazon's CEO Jeff Bezos offered an apology to customers. He claimed that the company sold out of its stock in less than six hours. Some Web journalists and bloggers suggested that Bezos' goal wasn't to offer a sincere apology -- it was to drive up more interest for the device [source: Sachoff].

When the Kindle became available again, the price dropped to $359. Amazon didn't release sales numbers to the general public, leaving many to question exactly how popular the device was. Netcasts such as CNET's "Buzz Out Loud" would occasionally report on Kindles listeners had spotted "in the wild." It seemed like the Kindle belonged to the realm of folklore -- you didn't own one, but a friend of a friend did.

Amazon got a huge publicity boost in October 2008. That's when Oprah Winfrey named the Kindle as her favorite gadget. Oprah devoted most of an episode of her show to promoting the Kindle. She invited Jeff Bezos to the show to talk about the device, explaining its features to her audience. Oprah also announced an electronic coupon for the device. Viewers could enter the code "OprahWinfrey" when purchasing the Kindle and receive a $50 discount.

Amazon announced in December 2009 that the Kindle was the top-selling item in the Amazon store for the holiday season. Today, you can buy an ad-supported basic Kindle for $79. The Kindle Touch models cost $99 for WiFi-only or $149 for WiFI plus 3G. The Kindle Keyboard models are $99 for WiFi only and $139 for WiFi and 3G. The DX is the most expensive at $379 and comes with free 3G access. And Amazon's tablet, the Kindle Fire, which uses WiFi only, is $199. Amazon also offers ad-free versions of these devices for higher prices.

While Kindle sales have grown since Amazon launched the device, the company hasn't been free of criticism. Electronic copies of books sometimes cost about as much as physical copies, something that seems unfair to some people. Unlike a physical book, there are very few production and distribution costs associated with an electronic file.

Amazon also got into hot water when it remotely deleted copies of George Orwell's "1984" and "Animal Farm" stored on customers' Kindles. It turns out the publisher that made the books available didn't have the proper rights. Amazon credited customers the money they spent on the books and apologized for the situation. The incident brought to light a potential problem with electronic copies of books. The bad publicity didn't last long, though. In July 2010, Amazon announced that sales of electronic books surpassed hardcover sales for the first time [source: Miller]

­Maybe you're a college student and you're hoping a Kindle will replace the ­need to lug around a pile of heavy textbooks. While a Kindle could hold an entire year's worth of college books (with room to spare), there's a problem. If the book has color illustrations or graphs, the Kindle won't be able to display them accurately. The Kindle Fire addresses this issue with its color screen but it doesn't have the robust battery life of the E Ink models.

With the surge in popularity of the Kindle and its competitors, the era of the electronic book seems to have arrived. Have we come to the end of the mega bookstore? And will there come a day when the idea of a physical book will be a quaint notion?

To learn more about e-books and related articles, peruse the links on the next page.

Lots More Information

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• Are e-readers making books obsolete?

More Great Links

• Amazon
• Reversing Everything

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