Infinite Loop / The Apple Ecosystem

Ars Technica reviews the iPad


Simple note-taking

Many of our readers asked whether the iPad could be used as a simple note-taking device in class or in meetings, and we think that it could—depending on the kind of notes you plan to take. If you're sticking to all-written notes, the most ideal note-taking solution would probably be to use the iPad with either Apple's keyboard dock or with an external Bluetooth keyboard, as this would allow for the quickest and most accurate text entry. (The on-screen keyboard isn't out of the question, but would likely be slower and more tedious than a hardware keyboard.) Taking notes in just the built-in Notes app could work (to be e-mailed to yourself later or synced with your computer), or, you could use a more robust application like Pages.

For those taking notes that might require drawings or equations, the question gets a little more complicated. The best solution we found for this (with a little help from the Internet) was a $0.99 app called SketchPad HD. This app allows you to draw on the screen using your finger or a third-party, iPad-compatible stylus, but you can also type notes in the same document. This could be useful for those taking physics or engineering notes and then syncing them later to a desktop machine.

The multitasking debate

by Jacqui Cheng

The iPad can multitask, but, just like the iPhone, it doesn't allow third-party applications to run in the background. Apple's applications can run in the background (Mail can check your e-mail constantly, and the iPod app will continually play music for as long as you let it). But third-party apps are what make the iPad, so Apple's stance on multitasking has real consequences for the platform. Apple has regularly made the argument that allowing third-party apps to run in the background could have serious effects on battery life, could cause an issue with overall performance, and could open the door for apps to let malware run in the background.

Despite this, there are rumors that Apple is considering some form of limited third-party multitasking support in the next major release of the iPhone OS. The most requested (or complained about) type of "multitasking" that users seem to want is streaming music—as it is now, if you want to listen to streams from Pandora or NPR, their respective apps must be in the foreground at all times or else the stream will stop. So, no rocking out to Pandora and then switching to Twitterrific to fire off a tweet unless you're willing to stop rocking out for those 30 seconds.

Another major complaint is from users who like to keep chat windows open at all times, whether those are through AIM or an IRC channel (IRC is particularly popular among our readership, of course). The official AIM app tries to get around this limitation by offering push notifications—when you log on via the iPad, the application keeps you online on the server so that when you exit the app, you don't log off. Instead, if someone IMs you when you're off doing other things, the server will push down an update to your iPad to tell you that you got an IM:

Those who want to keep IRC running in the background are more out of luck, as are the users of practically anything else that you might normally keep in the background. Heck, even Apple's own native Videos app doesn't keep running in the background if you decide to interrupt your own video with a quick check on the weather. It can get frustrating, even for non-techie users.

There is somewhat of a debate brewing over whether users really want this level of multitasking. Although much of the debate is being carried out by Apple fanboys versus Apple haters, there are some serious issues at stake (if you can get past the poo flinging).

One of the reasons some of us like the iPad is because it forces us to stop trying (and usually failing) to do so much at once. Focusing on one task is mentally liberating, especially to those of us who tend to go overboard with tabs, open applications, and stress in our normal computing lives. (Some—but not all—of us involved in this review actually want a computing device that actively forces us to multitask less when we're not working.) At the same time, for the reasons stated above, the inability to keep certain things running in the background remains a serious crutch for a considerable chunk of users. Luckily, this is not a hardware limitation of the iPad, and therefore can be improved upon in the future if Apple chooses to do so. We can only hope that Apple comes up with an elegant solution to this problem, and soon.

Hardware breakdown

by Jon Stokes

The main application processor that powers the iPad is an Apple-designed system-on-a-chip (SoC) called the A4. Based on the same ARM Cortex A8 processor core and PowerVR SGX GPU core that power the iPhone 3GS, the A4 ups the clockspeed to 1GHz (compared to the 3GS at 600MHz) and gets more performance in exchange for a higher power draw. The exact nature of the advances, if any, that Apple itself contributed to the A4's design has been the subject of much speculation. Unfortunately, the benchmarks that we present here don't shed much further light on the subject. Neither does an otherwise interesting teardown done by iFixit—that is, unless Apple's contribution is not in the SoC design but in the packaging.

The iFixit and Chipworks teardown and X-ray analysis reveals that the A4 is a standard package-on-package (PoP) design, with three different chips crammed into two different packages and connected via wire bonding. At the bottom of the stack is the SoC itself, and positioned above it is another package containing a pair of 128MB Samsung memory chips (Samsung K4X1G323PE). iFixit's teardown and subsequent examination of the SoC also confirms that it's single-core—the only possible conclusion based on the size. In all, iFixit concludes, "There's nothing revolutionary here. In fact, the A4 is quite similar to the Samsung processor Apple uses in the iPhone. The primary focus of this design was minimizing power consumption and cost."

iFixit's cross-section of the iPhone's processor, which uses the same PoP format as the A4. Notice the three dies stacked in two packages. Source: iFixit

As for the GPU, iFixit cites others' reviews for their conclusion that the GPU is the same PowerVR SGX 585 found in the iPhone 3GS, and until more in-depth software analysis is run, we see no reason to disagree with what was rumored to be and indeed appears to be the case.

Of course, observing that the very first iteration of the A4 doesn't appear to confer on the iPad any real advantages beyond what would be available from third-party vendors isn't the same as saying that Apple isn't serious about eventually making a bespoke ARM SoC that's customized to the iPad to a degree that it confers a real, double-digit advantage in some key metric (i.e., performance, power, or performance per watt). Apple bought P.A. Semi in mid-2008, and, even if we disbelieve the rumor that most of P.A. Semi's core team promptly quit and went elsewhere, that's still not enough time to do a whole lot of in-house, custom work on a brand new IC. I think we'll have to wait for later versions of the iPad—and later versions of the iPhone, iPod, and as-yet unannounced products—before we really get a sense of what Apple can do in this area.

Other ICs and components that the teardown revealed were: a Samsung MLC NAND flash module, a Broadcomm I/O controller, a Broadcomm wireless module (802.11n and Bluetooth), and chips from TI and NXP. iFixit also found that, "iPad actually has two batteries wired in parallel, for a total of 24.8 Watt-hours." In all, this gives the iPad 5.5 times the battery capacity of the iPhone.

The other relevant tech specs are either still unknown or were revealed by Apple at launch. In all, the post-launch investigations have so far confirmed what we pretty much already knew: the iPad is essentially a fantastic screen, two big batteries, a 1GHz A8- and PowerVR-powered SoC, with some I/O and memory hardware squeezed in there. It's lean, and it's very mean, but any magic Apple pixie dust resides firmly in the software side of the equation. With the exception of the unibody aluminum case, there's nothing in the hardware that competitors can't, and won't, copy in short order.

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