A minor optimization

| Comments (7) | Misc
The elevator in the International Terminal at SFO only goes to two floors. Internally, it has two buttons, for the top floor and the bottom floor. But of course, when you get in it's either at the top floor or at the bottom and the only place it could go is the other floor. So, at most, you only need one button: next floor. I guess this would need a different internal design for the elevator software/firmware/wiring, but the programmer in me does find the current arrangement a bit inelegant.


Why have a button inside the elevator at all? Its obvious once someone enters the elevator what the destination is.

Doesn't apple have an similar elevator in their Japanese apple store?

Solid point but realize it's do to the laws in California, not the elevator designer. All elevators must follow a strict "user interface" if you will for people of disabilities.

After reading a bunch of user-style documents one day, I wandered off to the elevator lobby, and noticed the elevator buttons, one for "up" and one for "down."

"Huh," I thought. "The down button is used 99% of the time from here, so it should be much bigger."

That's when I decided to take a nap.

The point of a human interface is that you need to provide something that the vast majority of the users can understand without explanation.

Two buttons is immediately understandable. One button is more elegant but it is a usability disaster.

What phb said.

I have since worked out what I so dislike about the one button interface, it is just like the one button power switch interface that is such a disaster.

Having one button for on and off is a modal interface, the user has to know the current state of the system to achieve the desired result. So press the on switch on the universal remote and the TV turns on but the amplifier turns off.

Windows machines are worse still as the power switch now has five different functions:

1) Turn the machine on when off
2a) Send the machine into suspend mode when on
2b) Send the machine into hibernate mode when on
2c) Turn the machine off when on
(which applies dependson the machine config)
3) Wake the machine up from hibernate
4) Wake the machine up from suspend.
5) Force a hard reset after a crash

The user has no idea which outcome is going to occur, particularly since the machine takes varying times to wake up depending on whether it is in suspend or hibernate. It is not unusual to wake the machine up and find that one has just unintentionally sent it into hibernate.

Feedback to the user matters. Complexity matters. This is a case where fewer buttons makes for a much more ambiguous and complicated interface.

In France recently I saw an elevator that had a button listed as "-1"...

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