Yesterday Microsoft announced their "Surface" line of mobile devices. I wrote that one of the problems with it is that it attempts to combine the best features of a tablet and a laptop, but in doing so it actually creates something that's the worst of both worlds. (A simplified explanation is that tablets are for consuming, laptops are for creating. Tablets don't replace laptops—they augment them.)
I was trying to explain my views in the comments of that article, and it occurred to me that we can build another triangle here.
You all know the old adage, "Fast, cheap, easy—pick two." (And you may remember the one I created three years ago about remoting protocols: low bandwidth, good user experience, low CPU—pick two.) Well today I'd like to introduce one that related to mobile devices like tablets and laptops:
Fast, light, long battery life—pick two.
If you want a mobile device that's both fast (high performance processor) and light, then you can't expect long battery life. If you want a device that's fast and has long battery life, then it's not going to be light (since it will have to be full of batteries to support that fast performance). And if you want a device that's light and that has a long battery life, then it's not going to be fast.
This is an immutable law of physics that applies to all mobile devices. Sure, better technology and Moore's Law will mean that the quantitative definition of each of these will constantly move forward. And "fast" might mean different things to different people. (One person might argue that the dual core A5 in an iPad is "fast," but it's nothing compared to a quad core Ivy Bridge. But that's fine. Apple chose the "light" and "long battery life" options instead.)
Let's apply this to real life to see it in action (and to understand why I created it in the first place). I mentioned yesterday's announcement of Microsoft's Surface line of tablets. There are two different models, the "Surface" which is thin, light, and ARM-based, and the "Surface Pro" which runs some sort of Intel Ivy Bridge but that's 33% heavier and 45% thicker.
So since the Surface did not go for the "fast" option, it can be light and have a long battery life. The Surface Pro has the "fast" option, but it's thicker and heavier and will most likely not have a battery life anywhere near as long as the regular Surface. (The Surface Pro has a 42Wh battery, which is typical of an Ultrabook-class device.)
To be clear, I'm not saying that any one of these options is inherently "better" than the others. It's a use case by use case basis. But the reality is that I want one combination of these options for some use cases, and other combinations for other use cases. (Light, long battery, but slower when I'm running around and fast when I'm stationary getting real work done.) So that's why there will also be a market for all three combinations of options—one type of solution will not "replace" the others (or all three).
The only future caveat to this is that maybe (maybe!) we'll get to a point where all three are "good enough" and it won't matter. But clearly we're not there yet. (If we were then Microsoft wouldn't have ARM and Ivy Bridge options—they'd just have the single "good enough" tablet.)