Inside the iPod Nano

We voided the warranty - so you don't have to. A look inside Apple's flashiest toy.

Inside every gadget a hundred stories lurk: What innovative memory, battery, or LCD design does it use? Where did the components come from and how do they work together? What previous design weaknesses needed fixing? And, maybe most important: How can users make the device work better for them?

Many of these stories can be teased out by ignoring that familiar warning: “no user-serviceable parts inside.” We pried apart Apple’s new iPod Nano - a music player so small that many customers are buying bulky carrying cases to make it harder to lose. But don’t try this at home.

A - Liquid Crystal Display

Analysts who have broken down the costs of the nano's parts say that the liquid crystal display accounts for almost 8.5 percent of the total. The 1.5-inch screen is the first color screen in any iPod other than the full-size version. In addition, the screen offers functionality - displaying homemade photogalleries and album art - that not so long ago was availalbe only in the iPod Photo, which cost $500 for a 40-gigabyte version. You can even use the nano to store and carry around your PowerPoint presentation. This might make it a deductible business expense.

B - Flash Drive

Other iPods (besides the shuffle) store music on a hard drive just like the one in your computer, only smaller. Instead of a hard drive, the nano uses flash-memory chips; these solid-state devices don't skip and use less power. In the four-gigabyte model, the flash memory is attached to a daughterboard; in the pictured two-gigabyte model, two one-gigabyte memory chips are soldered onto the motherboard. Samsung, the worlds's largest supplier of flash memory, makes most of the memory chips used in nanos. Around the time of the nano's debut, reports circulated that Apple had bought almost 40 percent of Samsung's entire production of such chips, possibly below market rates.

C - Battery

Like all iPods, the nano has a rechargeable lithium-ion polymer battery. The battery's polymer electrolyte allows designers to mold the battery like modeling clay and also obviates the need for the organic solvent used in previous designs. This is a particular advantage for a product designed to go into a pants pocket, as the solvent had the bad habit of occasionally igniting.

Like most lithium polymer batteries, this one uses a fast-charge system that restores 80 percent of its 14-hour charge in about an hour and a half; the remaining 20 percent takes another hour and a half. Still, even this battery will eventually die after a few years. The fact that no iPod is designed to allow the user to replace the battery led to a customer class action suit that Apple settled in June 2005. But even though pulling your iPod to pieces, as we've done here, voids the warranty, many third parties have offered longer-life replacement batteries for previous iPod models (with replacement instructions) and may do so for the nano.

D - Polycarbonate Skin

The nano's skin is made of the same polycarbonate that covers the screens of other iPod models. Many polycarbonates are tough enough to serve as bulletproof glass - indeed, the website Ars Technica ran a car repeatedly over a nano without breaking its skin. But though impact resistant, the material is easily scratched. Soon after the nano was introduced, Apple faced another class action suit claiming that the iPod scratches much too easily, because its screen has a thinner polycarbonate coat than other models'. An Apple executive reportedly replied to complaints by saying, "You keep it in a pocket with your keys?"

E - Cache Memory

In hard drive-based iPods, cache memory plays the crucial role of continually storing blocks of music decoded from the hard drive. If the hard drive, like a vinyl record, skips from being knocked around, as can happen at the gym, the cache can stream music without interruption. The flash drive in the nano is solid state instead of mechanical like a hard drive, so there's no way it can skip. As a result, the four megabytes of Samsung dynamic-random-access memory aren't used so much for caching as for general memory for the nano's main processor and operating system, just as in a regular computer. This means there's more memory available to let the system handle images and long lists of songs, or to reduce the number of times the processor has to fetch data from the flash memory, which saves power and extends battery life.

F - Portal Player Chip

You've stored a thousand songs on your nano, but that's as 1s and 0s. The processor - the same type that powers the full-size iPod - is hard-wired to translate data taken from the flash drive into analog sounds, amplifying them before they reach your headphones. Just like the large and power-hungry CPU in your desktop PC, the processor also manage files, the user interface, and digital rights management software for the music you've purchased from Apple's iTunes Music Store.

G - Click-Wheel Controller Chip

From the start, the iPod's signature feature was its wheel controller. Though the click wheel doesn't register how hard you click, it does respond to how you touch it: the farther you scroll, the faster you scroll. This makes it easy to move through a list of then thousand songs. Apple touted this feature when the first iPod came out in 2001, with a wheel that physically rotated. Its successor, the first touch-sensitive wheel for the iPod, was built by Synaptics; to develop the nano's click wheel and controller, however, Apple contracted Cypress Semiconductor. No parties are talking about why the switch was made, but perhaps a clue to (or merely a result of) the decision is the fact that Creative Technology's Zen Touch MP3 player uses a Synaptics touch pad.