[moe]

I don't know about your simulation, but over here in the real world it doesn't work that way.

Many people don't dry their hands at all in a public bath room (that's what god invented jazz hands[1] for).

By combining faucet and dryer you force these people into the same bottleneck as the hand-dryer users.

[1] http://www.youtube.com/watch?v=xuPSIbABYVU

[oh_sigh]

> I don't know about your simulation, but over here in the real world it doesn't work that way.

Wow, great point. You're obviously unbiased! You don't even know the details of the simulation, but you're confident that you really know what's up based on your presence in "the real world".

> Many people don't dry their hands at all in a public bath room

Yes, but they still wash their hands. Many people don't dry their hands because they have to use the hot air blowers, which they know are ineffective. If they see an effective device, some members of that group will choose to use it instead of jazz handing. But even discounting those people, the wash + dry combination still works out better for most cases I can devise. The only universe I have come up with where wash and then dry else where is better than washing and drying at the same station is if there are an equal number of paper towel dispensers as there are to sinks, which has never happened in a bathroom where the number of sinks > 2, as far as I know.

> By combining faucet and dryer you force these people into the same bottleneck as the hand-dryer users.

I wasn't arguing for optimizing any one special interest groups time spent in the bathroom, I was optimizing for the total network throughput of the bathroom.

[moe]

I was optimizing for the total network throughput of the bathroom.

But you didn't. You have serialized access to two resources that were previously independent.

Since a significant portion of users need only one of the two resources you have created a new point of contention. For access to the faucet not only do I have to wait for people washing their hands, now I also have to wait for people drying their hands.

[petsos]

Yes but one of the resources (the dryer) has increased significantly too. And since we are both using the word "significant" instead of any real numbers we can prove either point.

[stcredzero]

I call BS. It should only take 6-8 seconds for someone to grab 2 pieces of paper towel once they're at the dispenser. That means 2 towel dispensers should be a match for 5 sinks.

[incongruity]

It's actually worse because you take what were 2 parallel operations (washing your hands and drying them) and make them two serial operations, not able to be run in parallel.

[oh_sigh]

Yes, it does upset the balance slightly for people who want to wash their hands, but not dry them, and for people who want to dry their hands, but not get them wet.

Those are the only scenarios where your argument holds, however.

[incongruity]

No, not at all.

Simply put, you are moving from 2 independent operations to 2 mutually exclusive operations – meaning that 1 sink (in the Dyson case) can only service 1 user at a time vs 1 sink+1 dryer/towel dispenser which can, at a minimum, service 2 users at once (there's actually a much bigger set of time/path calculations that could go in to this, but the simple case is enough to make it clear that your thinking is confused on this.)