How Apple stretched its wings with the iPhone 5s hardware design

Like most midcycle Apple smartphone releases, the new iPhone 5s doesn’t look that different from its predecessor: A few improvements to the finish, new color combinations, and some minor cosmetic changes are all that separate it from the iPhone 5—at least on the surface.

Dig a bit deeper, though, and you’ll find some significant under-the-hood differences in the latest handset to leave Cupertino’s design labs, giving us some key clues about the tech giant’s long-term plans for its mobile platforms.

We have the technology

The first big change beneath the iPhone 5s’s screen is, of course, a new CPU—the A7 (in keeping with the Apple numbering scheme that debuted with the A4).

As you’d expect, the A7 is faster than its predecessor—twice as fast, according to the company. More interestingly, it also sports a 64-bit architecture, which puts it firmly in the big leagues of CPU design.

This means a few things. First, the A7 can use twice as much data at any one time as its predecessor could, making it easier for apps to crunch larger numbers and perform more-complex operations without having to hit the phone’s internal RAM. Apple also doubled the number of registers—special locations of memory that are baked into the CPU and therefore can be manipulated at very high speeds—further increasing the processor’s capabilities and performance.

In addition, the A7 appears to have a 64-bit bus; if so, it will be able to address a mind-boggling 16 exabytes of RAM, compared to the 4GB possible with the A6, opening the door to significantly more-powerful mobile devices in the future.

Playing with the big boys

In short, the A7 is, as Apple’s Phil Schiller pointed out during the iPhone 5s’s introduction, a desktop-class CPU, which raises the possibility that the company’s mobile processors may one day find their way into Apple’s laptops and desktops—a prospect that I pondered nearly three years ago.

Given how things have evolved since, the A7’s capabilities may simply indicate that Apple is working as hard as ever to free its mobile hardware of the compromises—such as reduced computing power and limited RAM—that technology has forced on it. As more and more consumers use their tablets and phones in place of (rather than together with) their desktop machines, it makes sense for the company to push its mobile capabilities as far as it can.

In true Apple fashion, these changes come at no cost to developers: All they have to do to take advantage of the A7’s new features is to recompile their code using the latest version of Xcode, and then enjoy the resulting speed bumps. The A7’s ability to crunch more numbers and produce better graphics will give game developers a boost and will improve the performance of iOS 7’s user interface, which relies heavily on complex visual effects.

Motion emotion

Alongside the A7, Apple is debuting the M7, a new chip that the company has dubbed a “motion coprocessor.” Its job is to deal with all the signals that come from the iPhone’s various motion sensors, such as its accelerometers, gyroscope, and GPS signals.

Previously, these tasks were the CPU’s responsibility, which often resulted in significant battery consumption. It was also overkill: Using an armored truck to transport a feather isn’t the best way to save on your gasoline bill. By building a specialized chip, Apple can more efficiently manage location-based apps, particularly when they’re running in the background. Obviously, this translates into better battery life (without having to make the battery significantly bigger); but it also gives designers the opportunity to make location-aware software more pervasive and feature-rich.

On the hardware front, the M7 is a great example of how Apple takes advantage of its control over its entire hardware product. Instead of going for a bigger battery or a less power-hungry CPU—goals that are difficult and perhaps impossible to achieve with current technology—the company is meticulously turning common functions into specialized components that allow it to push the boundaries of what its devices can achieve.

Apple points out some additional possibilities opened by the M7’s capabilities, such as its ability to detect the difference between traveling by car and traveling on foot. For example, Maps can use iOS’s location features to automatically switch from driving directions to walking directions after you’ve parked your car. And since the 5s can tell when you’re driving, it won’t pop up prompts to join every Wi-Fi network you pass. It can even save battery life by reducing the frequency of network checks when your phone hasn’t moved in a while. All of these advances go beyond making your phone faster; they help improve the things you do with your device.

At the tip of your fingers

No hardware change in the iPhone 5s is going to be more noticeable to users than the introduction of Touch ID, Apple’s fingerprint scanner. Touch ID has already been widely covered in the press (including, of course, by Macworld), and, given the sensitive nature of the information it collects, it has generated a fair amount of controversy.

I was a little surprised that Apple didn’t shed a bit more light on the design decisions behind Touch ID while introducing the iPhone 5s, particularly considering the ongoing brouhaha over the revelation that various governments may be snooping into the Internet lives of their own citizens. The good news is that the fingerprint sensor built into the company’s new handset seems to be hardwired into a special area of the A7 processor, and that a user’s biometric data won’t be available to the software that runs on an iPhone until a one-way algorithm has transformed it into a mathematical representation.

For all practical purposes, this means that—unless it can force Apple to somehow modify its hardware—no government agency (or other ill-intentioned party) will be able to use an iPhone to surreptitiously capture our fingerprints in any usable form. And lets face it: If the NSA has that much sway with the folks in Cupertino, it can get them to work on far nastier things than taking pictures of our thumbs.

That said, the issue of securing your phone with a fingerprint versus using a passcode has some potentially interesting legal ramifications, though we may not see those tested in the real world for some time.

Stronger, faster, better

All things considered, far more is at work behind the screen of an iPhone 5s than just a faster processor. The technology that powers iOS devices is rapidly evolving from its embedded computing roots into a powerful platform with fewer compromises and increasingly specialized capabilities.

With a 64-bit processor and custom chips that take some of the heavy lifting off that powerful CPU’s shoulders, Apple is free to use its hardware to explore in new directions—while putting more power than ever into our pockets.