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 could replace the battery if it failed. 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. And similarly, the Kindle Paperwhite models can reportedly last eight weeks with WiFi off, 30 minutes of reading time daily and brightness turned down to 10 from the maximum setting of 23. 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.
Above 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.