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Comment by ryanelkins | Hacker News Reader

I thought this was a pretty interesting article but I don't really buy the analog vs digital watch comparison. Mostly I don't agree that turning the crown is only 9.5 bits. There are 720 possible combinations and you have to move through on average 180 of them to get to the right time (assuming you can move forwards and backwards). Each tick of the crown is a movement, just as each button press is. In that case the analog watch drops to just over 5% efficiency.

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I'd argue that the crown is more like choosing one value from a set.

He is overshooting it, but so are you. Really, you just need to know when it's time to stop turning the crown, and that's all.

You won't stop at the exact position, so there are going to be some adjustments that need to be made, but overall it's quite close to 9.5 bits, as he says.

Do you mind explaining how you get to your number of 9.5 bits? I'm just trying to understand this. It seems like you have to iterate through the variations one at a time - just because turning the dial quickly lets you iterate through them quickly doesn't mean you're not actually going through them one by one. I don't see how turning the dial and pressing a button are different in that regard other than you can iterate with a dial much faster than with a button.

I guess I mostly don't see how he defines turning a dial as being equal to 9.5 bits. I understand why he says it would take that many bits to store that decision, but not how a dial gets you there.

Bits of information in information theory dealing with information compression are defined by choices. So it is choices you're looking for, not actions. The guy's article is not technical, though he seems to think it is; it is more of a sentiment, a way of thinking about a problem domain, an approach.

To that extent you're not "going through them one by one", but getting into the proximity, then backtracking (or advancing slowly), and only then going through one by one for a dozen or so variations until you reach your desired option (roughly). It's not as technical, or as precise as he presents it to be, but this approach of tackling UI complexity does give usable approximations of complexity, even if imprecise.

EDIT: or, what jcromartie said http://news.ycombinator.com/item?id=1242929

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