Unless you do design for something totally unambiguous like mobile phone OSs, you might has "what do you mean by mobile?" And the answer is indeed a bit soft.

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Even when we started this, in fall of 2010, a lot of direction was "mobile phones." But even in the past few months, tablets are starting to be pretty regularly regarded as mobile. So we have a vague direction that is bigger than just one-handed handset-sized devices. Explict mention is made of kiosks, tablets, GPS units and other such devices.

Before we launch the book, we'll finish this section. Not that I expect it to be clean and easy and without arguing amongst ourselves. And unless we do a great job, you are 87% likely to disagree.

Outline eras of mobile...

  1. Voice
  2. Paging and Text
  3. Pervasive network connectivity
  4. General computing devices

If you consider a current mobile phone as a generally 4th era device instead, what you find is they are:

This means that all sorts of other devices, like tablets and MIDs and game devices, are Mobile.

More interestingly, if you start losing individual definitions, even more comes into play. GPS devices are only a bit unconnected; some have full network, some have FM traffic reports. But why draw a bright line between them based on connectivity, if all other factors are the same, and you design them the same way?

This leads to definitions more related to "small screen" and "interactive." It lets even embedded devices (printers), media-capture (camera) and playback (mp3) devices play. And actually looking at the patterns, the vast majority apply to all these device.

I think if you consider the convergence chart (not originally from, but visible at http://shoobe01.blogspot.com/2010/10/f8-and-be-there-what-mobile-convergence.html), and consider what happens to all those converged devices, interesting things occur. Now, what if you take out the backbone, and let there be MIDs (iTouch, etc.) that do everything but telephony? Might be good as an anchor to build the argument from, or another axis of argument. Plus, nice image.

OTHER THOUGHTS:

This needs work. Some of us think it's all small screen devices. Connected or not.

Connectivity away from the wall is another definition. But kills many game devices. And actually, GPS, and so on, since they are receiving only.

Restrictive interactions also seems valid. At least as an edge case; why can't the same patterns be applied very often to say the LCD on your photo-printing inkjet?

Need to define this. What's your opinion?

What Patterns Do You Cover?

Good question. And right now, it's purposefully muddled. We don't generally talk about hardware, except for labels and key functions and and keyboard layouts. Because those are pretty easy to change, and directly impact the on-screen interactions. Though we /could/ talk about how people with gloves, or dry fingers, or who just hate touchscreens should also have a scroll-and-select keys, at least as backup. But, that's pretty high level handset design, so not really worth fighting in a book like this.

So, the definition is pretty much on-screen, and things that directly impact the on-screen experience that are plausible to consider changing, for at least an operator/carrier to change, even if not everyone can.

If you have the ability to influence hardware design, then you can still get some hints from the patterns and principles contained here. We also, likewise, make lots of references to complying with the principles of the OS, as well as having principles that may conflict with any particular OS. So, if you design operating systems, then you have some other patterns and principles and guidelines to work off as well.