In fact, I think this app compatibility is a major reason Apple didn't offer a Retina display on the first iPad mini. For the iPad mini to be immediately viable, it needed apps. Not scaled-up or -down apps, but optimized apps. (Many people who use a Google or Amazon tablet are nodding their heads right now.) For both practical and technical reasons, I don't think Apple could have given the iPad mini a display with the full-size iPad's 2048-by-1536 resolution--consider that such a resolution at the iPad mini's smaller size would have given it the highest pixel density of any Apple product. So a Retina display on the iPad mini would have been one specifically optimized for the mini's size, and yet another resolution for developers to target. That would have meant only a handful of iPad mini-optimized apps available at launch, with other apps scaled up or down. I think a Retina iPad mini, with its own resolution, will happen someday (likely next year), but only after the iPad mini has sold in the millions and is an established part of the iPad lineup.
For now, any iPad app on the App Store will work with the mini. In fact, if you've already got a full-size iPad, you can restore your iPad mini from an iTunes or iCloud backup of that full-size iPad. I did that with one of the two iPad mini units I tested, and after a couple hours, the mini was a smaller-but-otherwise-identical version of my third-generation iPad, complete with several hundred apps and all their settings; the same playlists and videos; and everything configured and ready to go.
(For the record, upscaled 2x iPhone apps look just as bad on the iPad mini as they do on a standard iPad.)
You're holding it right
When I asked on Twitter and on App.net for questions people had about the mini, the second-most-popular topic (after questions about the display) revolved around what it's like to hold the iPad mini for extended periods.
The iPad mini's chamfered edges aren't just for looks; they also make the front edges more comfortable when holding the iPad mini in your hand. And though the squared-off back edges don't feel quite as nice as the tapered edges of the standard iPad, the mini is so much lighter that it's much more comfortable to hold for extended periods. Chances are, you won't be holding the mini with your hand all the way around the back, like the actors in Apple's TV ads do, but it's light enough to hold in portrait orientation by placing your hand behind the back and your thumb either on the bottom bezel or along the longer side.
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