Molecule-sized logic gates not small enough? why does this sound ridiculous? you are aware that nanites will probably be on the size order of viruses and bacteria or even as big as animal cells, there's plenty of room for even a supercomputer made of molecular electronics with loads ofroom left over for the internal machinery.
Grey-goo may occur, it's the nanite version of cancer, it's possible, just not a very big threat (have you ever seen cancer cells infect people nearby the victim?)
As far as these six points, the SD.net article outlines eight, oh wait, my bad, you meant the article I linked.
OK, let's look at this from the perspective of nanobot #1. Just to be generous, let's visualize the nanobot as a tiny little worker spacecraft that you control, so it has your human intelligence (rather optimistic for a nanobot, but I am trying to be generous). Your objective is to help the other 99,999 nanobots build a ruler, but from your perspective (inside a 10 micron wide nanobot, so you've been shrunk to roughly 1/200000 your original size), this six inch ruler is more than thirty kilometres long! Worse yet, there are some serious logistical problems to work out:
Let's start here: comparing a robot, no matter how small, to a human worker is a stupid notion if you've ever watched assembly lines for delicate or numerous products like circuit boards or microchips. Those robots can move almost faster the you can discern with amazing accuracy and timing, things a line of human workers would not be able to accomplish without many more hands that the one wielded by our little robot friend. Secondly, THIRTY KILOMETERS?! Oh my, we've never built things that long before- oh wait, yes we have, plenty of times, here's
one example.
1) How do you co-ordinate your activities with the pilots of the other nanobots? Is there a commander nanobot? Are there middle manager nanobots? Who assigns nanobots to which part of the ruler?
It's called math, genius, each robot has a set of fixed dimensions or at the very least a range of dimensions that can be monitored and controlled, like forming al ine for excercise by spreading your arms and touching the fingertips of the person next to you. Simple addition and environment awareness solves this problem.
2) How do you know where to start, ie- how do you decide where one end of the ruler is going to be, and where the other end is going to be?
See above, just pick one bot as the start and then measure out till the length of the bot-chain equals the length of the ruler.
[quote3) How do you communicate with the other nanobots? Radio transmissions? How do you communicate clearly with tens of thousands of other nanobots simultaneously? How do you align your movements with theirs? How do you plan?[/quote]
If you don't understand the concept of planning, you're a lost cause to humanity.
4) How much fuel do you carry? That little nanobot vehicle of yours doesn't run on the power of positive thinking, so how much work can it do on a full tank? Where and how do you refuel? How long does it take you to refuel?
Nanomachines require very little power and can probably be built to run off waste heat from the surrounding environment and supplement that with current passed along connected bots.
5) What is your propulsion system? You're not getting a free ride in someone's bloodstream like the sort of nanobot which looks for cancerous cells (a more sensible application of nanotechnology), so how do you maneuver about on the manufacturing table in order to help assemble this ruler? How do you jet up into the air to get on top of it if you need to? How much power do you have to combat gravity and air currents?
I surprised he didn't think of working in fluid, isn't this person supposed to be... I dunno, smart?
6) How do you deal with lost nanobots? In a normal manufacturing environment, air currents, static discharge, and other environmental disturbances could easily blow a nanobot out of the group or seriously damage it. Does the plan adjust automatically for worker turnover? Or must this ruler be manufactured in a vacuum-sealed clean-room environment? This is rapidly shaping up to be a ridiculously expensive ruler!
a nanobot is a nanobot, who cares if they get damaged, just toss away the broken bits to be recycled and send in reinforcements, these little guys are supposed to be cheap and expendable
7) How much payload can you carry? If you're grabbing molecules or tiny particles and attaching them to this ruler, where do you get them from? How many can you carry per trip? How much energy does it take to weld each chunk of metal to the ruler? Do you realize that if you use larger particles per trip, the resulting ruler will have greater porosity? What are you going to do, weld molten metal into the gaps? Consider the energy costs of doing that!
again, water solves the problems, just pump the raw material into the assembly vat as a solution, going back to my claims of prefabricated nanobits, you can even attach some nanites to the material so they can deliver both material and replacments at the same time
8) How do you assure dimensional accuracy of the overall ruler? The nanobot working on the other end of the ruler is (as far as you're concerned) more than 30 kilometres away, remember? How do you know he's not higher than you are? Do you set up a laser-based perimeter system in order to confine your activities within simple geometric bounds? If so, how do you make more complex shapes than a flat ruler? Do you use tooling in order to confine your activities? If so, what conceivable advantage does this process have over simple die-casting?
Yeah, how do we build roads or bridges or buildings with any amount of accuracy? Again, the answer to this problem posed by a supposed adept in the field of dealing with things too small to see with the eye is, surprise surprise, MATH. And again, having a scaffold of nanites with predictable and controllable forms really helps with measuring out distances that dwarf individual bots.
Who'd've thunk it? Obviously not this guy.
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Having realized I shouldn't be bashing the SD.net article, becuase that's not what Uso mentioned in his previous post, I will go on to address what he actaully said regarding
this article.
Actually, I don't need to, because the article itself poses solution or lines of inquiry to solve each problem.
Uso, I'd accuse you of cherry-picking data if I was certain, but you're probably just not reading the entire article like I have, so you're just missing the bits where the problems you pose are resolved or at least provided a path to a solution.