The Internet has been rife with speculation about the supposedly-coming-at-the-end-of-the-month Apple tablet (even I have weighed in), but recently, John Gruber has written a pair of articles that have really nailed it. I recommend reading both, but in a nutshell, this is the crux of the problem that an Apple tablet faces:

\"And so in answer to my central question, regarding why buy The Tablet if you already have an iPhone and a MacBook, my best guess is that ultimately, The Tablet is something you’ll buy instead of a MacBook.\"

If this turns out to be true (and honestly, this is the only plausible reason I've heard why might make a tablet), then there are three areas that are going to make or break this thing:

What CPU will it use?

In order to provide a pleasurable experience, the Apple tablet will need to have a powerful CPU, even more powerful than the iPhone. A larger display will allow for more activities — displaying web pages in their full glory, using JavaScript-heavy web apps, and playing back advanced media formats. For example, last year Apple introduced iTunes LP — a new format that presents music albums, accompanied by pictures, lyrics, artwork, and video. In the iTunes system requirements, Apple states that iTunes LP requires a 2.0Ghz Intel Core 2 Duo processor, 1GB of RAM, and a screen resolution of at least 1280x800. And Apple isn't really kidding — my first generation MacBook Air, with a 1.8Ghz Core 2 Duo, struggles to play the one iTunes LP that I have purchased. So presumably, since Apple wouldn't make a Tablet that could not play an iTunes LP album, these requirements can be viewed as the \"minimum\" specifications for an Apple tablet.

With that in mind, what are Apple's CPU options? Here is what I can think of:

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1. Use a full-power Intel Core 2 Duo
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2. Use a slow/low-power Intel Atom
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3. Use some sort of ARM CPU (like in the iPhone)
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4. Or, the dark horse, use a PowerPC chip
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I think that both of the Intel options can be ruled out. While the Core 2 Duo is definitely fast enough, it is too expensive, too bulky, and uses too much power to fit well in a tablet form factor. And while the Atom uses less power than a Core 2 Duo, it's far too slow to handle an iTunes LP, barring heavy optimization from Apple.

When initially thinking about this problem, I thought that there was a strong chance that Apple could return to the PowerPC, a processor architecture that used to be the heart of the Macintosh until the switch to Intel. Back in 2005/2006, there was a fabless chip company called P.A. Semi, which was building a 2Ghz, dual core, PowerPC chip that used a mere 7 watts of power. I believe that the chip was finished, and actually delivered on it's claims, and thus would certainly have enough power for the tablet. Adding fuel to the fire, Apple actually acquired P.A. Semi back in 2008. However, after doing some reading, I think that the P.A. Semi processor still uses too much power for the Tablet, and would require some chipset work. And finally, even though Apple has a strong PowerPC code base, I don't think that they want to support 3 different CPU architectures going forward. There just isn't enough development going on in the PowerPC ecosystem in order to justify the cost in software maintenance.

So, that leaves ARM. I don't think that the current state of the art in ARM CPUs, the Cortex A8, is fast enough for the tablet. This is the CPU that is in the iPhone 3GS and Palm Pré, and it just isn't fast enough to do heavy web surfing. However, Arm announced the Cortex-A9 last year, which can do up to 4 cores, each running at up to 1Ghz, in a low power envelope. This is the core that will be featured in the upcoming OMAP4 processor from Texas Instruments, and it sounds like it might just be powerful enough for the tablet.

However, according to what I've read, we're not going to see products with the OMAP4 Cortex-A9 CPU until late 2010 or early 2011. The NVIDIA Tegra 2 also apparently has a dual-core ARM Cortex-A9 in it, and could possibly ship before the OMAP4 chip —but both of these chips are going to arrive to late to be featured in Apple's tablet, if the rumors are to be believed.

And this is where I think that P.A. Semi comes in. I think that Apple has licensed the ARM Cortex-A9 architecture directly from ARM, and will produce their own CPU, shipping before the rest of the industry. In short, I believe that Apple purchased P.A. Semi not only so that they could control their own mobile CPU destiny, but so that they could ship products with the latest and greatest CPU technology before anyone else.

Furthermore, while the ARM Cortex-A9 probably isn't quite fast enough to make for an awesome tablet experience, I think that Apple will leverage it's software strength (including use of Grand Central Dispatch and OpenCL) in order to make sure things are optimized enough to make using the tablet for everyday tasks a joy.

How will text input work?

This is potentially the most critical piece of the entire design of The Tablet, and I think that this runs counter to most people's expectations. I mean, if The Tablet is designed solely to consume content, then why does text entry matter? My argument is that because the Internet is inherently a two-way medium, that you enter in text a lot more often than you think. Blog comments, Facebook status updates, short e-mails that get much longer as you type them, etc. If the text input mechanism on The Tablet is really crappy, then you're going to find yourself in a situation where you have to put the thing down and go to your computer in order to accomplish a certain task effectively. And if Apple is truly aiming at the MacBook with this thing, then they need to minimize instances of that.

That said, I have no idea how text input will work on The Tablet. I think that lack of good text input capabilities has sunk pretty much all other tablet efforts, so my guess is that Apple has something up its collective sleeve here. I'll go so far to say as that it wasn't until Apple solved this problem, that they went ahead full speed on The Tablet project. A couple of ideas — the back of The Tablet could be a touch surface, so that when holding the tablet with both hands, your fingers are free to type using the back of The Tablet. Or, the keyboard could be split into two halves, one in the lower left and the other in the lower right corner. This would enable your thumbs to do all of the typing, much like on the iPhone currently. I think that Bluetooth keyboards won't be supported (even though Apple makes a decent Bluetooth keyboard).

But in general, I think that text input on The Tablet has to be strong in order for it to succeed. And because Apple is Apple, I don't think that they'll launch with anything that is less than great, and with something that I never would have seen coming. That's why it's fun to pay attention to them. ;)

Will it support Flash?

The issue of Flash is tricky, and I'm not 100% sure where I stand. John addressed this in his most recent article, where he states that he doesn't think that The Tablet will support Flash:

\"For most of the same reasons why I don’t expect the iPhone OS ever to support Flash. Flash is the leading cause of application crashes on Mac OS X. It is buggy. It’s inefficient. Presumably The Tablet is going to have a faster CPU and more RAM than an iPhone, but that doesn’t mean Apple isn’t going to treat CPU cycles and memory as any less precious than they do on the iPhone.\"

I'm more or less inclined to agree. The Internet as a whole is certainly moving away from Flash. And in general, Apple likes to skate to where the puck is going to be, not where it is today. But if Apple does indeed ship a large screen tablet without Flash, there will be two main problems:

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1. There is a lot of existing Flash-based content on the Internet that people will want to view, and
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2. There are a lot of Flash-based advertisements on the Internet that people won't see (and publishers won't get paid for displaying)
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And in general, Apple likes to respect other business models, and wants people to be able to view the content that they want to view. So while I agree with John Gruber that Apple probably won't support Flash on The Tablet, there is a (small) chance that they could. And aside from all of the aforementioned problems with Flash, John Gruber nails the really big issue (from Apple's perspective):

\"To my knowledge, Apple controls the entire source code to the iPhone OS. That’s not to say they wrote the whole thing from scratch. Many low-level OS components are open source. But they have the source. If there’s a bug, they can fix it. If something is slow, they can optimize or re-write it. That is not true for Mac OS X, and Flash is a prime example. The single leading source of application crashes on Mac OS X is a component that Apple can’t fix.\"

There are some components in iPhone OS to which Apple doesn't control the source code, but they are minor (you can see them if you open Settings → General → About → Legal on your iPhone). So, the only way I see Flash working on The Tablet is if Adobe were to grant Apple a perpetual license to the full source code of the Flash client. In that way, Apple could have the source, and tailor it to suit their needs. This would be fairly similar to how Java works on Mac OS X — Sun writes the JVM, but Apple has a source code license, so that they can make their own tweaks before shipping the JVM on Mac OS X.

And while I don't know that Adobe has ever licensed the source code of the Flash player out to a 3rd party, or if such a thing is even possible (Adobe might not own all of the code in the Flash player), it's clear that Adobe is desperate to get Flash on Apple's devices. So if Apple said that they'd do Flash on The Tablet, but only if they got the source, then it's clear to me that Adobe would be pretty motivated to fulfill that request.

Conclusion

Even after all of this speculation, I'm not really sure that I even want an Apple Tablet. And I think that speaks to the crux of the problem — why The Tablet is much harder to design, engineer, and market than the iPhone. In the lead up to the iPhone, even though I didn't know anything about a then-mythical Apple phone, I knew that I wanted one. Badly. I despised my Nokia 6600, and I didn't really see anything else in the market that I knew would make me happy. So when Apple announced the iPhone, I couldn't wait to get my hands on one.

But with The Tablet, I'm not sitting around, pissed off at my current tablet, waiting for something better. I'm happily living my life, without any tablet whatsoever. So Apple has to not only engineer a kick-ass device, but they also have to engineer the need for one in my life. And that is a significant hurdle to overcome.

But if anyone can do it, it's Apple. And you know what I'll be focused on come January 27th, because if anything, the future sure is going to be interesting.

-Andy.