[extropy-chat] self replicating machine ....

[Dan Clemmensen]

Adrian Tymes wrote:

>--- Dan Clemmensen <dgc at cox.net> wrote:
>  
>
>>For this exersize, we must consider the paper (or other substrate)
>>and 
>>the rather exotic inks
>>as raw materials. At the system level, a small production plant for
>>the 
>>paper and a small production
>>plant for each of the inks is likely to be a whole lot easier to
>>build 
>>than even the smallest conceivable
>>infrastructure based on silicon wafers.
>>    
>>
>
>Or possibly thin sheets of rock instead of paper, depending on the
>intended environment; the printer would be modified accordingly.
>
>  
>
I changed my mind. Rather than using a technology based on X-Y plotters that
create plots for humans, let's look at technology that is specifically
designed for optimal self-replication. We want to use simple substrate 
materials
and a simple design. My guess is that we can design a system that can 
use crude
electromechanical actuators to achieve 10 micrometer resolution on a simple
plastic substrate. This is 100 times coarser than the current state of 
the art in silicon
lithography (90nm) and 1000 times coarser than the state of the art in STMs.
An STM uses exotic piezoeletrical materials. My proposed technology uses
macro-scale servomotors.

If we have a 10-micrometer resolution, a 32x32cm page has one billion 
pixels.
For ROM, we get 8pages/GB. I assert that we can describe a 
self-replicator in about
1GB, given a substrate consisting of iron bar stock, celluloid sheets, 
copper wire, and
At most seventeen other inputs of equivalent complexity.

This self-replicator is a general-purpose machine. The instructions for a
number of instances of this general-purpose machine to produce the 20 
substrates
(e.g. copper wire) from a simpler substrate (e.g. copper ore) should 
take less than
1 GB. So the total ROM occupies 21x8=180 pages.

The actual  circuitry for the replicator occupies perhaps 8 pages. We 
are still in the
range of 1Kg for the information needed for a self-replicator with a 
simple substrate.

An instance of the self-replicator will be perhaps 100Kg. If this single 
instance cannot
successfully produce all 20 substrates, and then reproduce itself, it 
will die.
 If we want to get brave, we can add a bootstrap to the replicator . If 
the replicator succeeds
in implementing the fundamental 20 substrates, the bootstrap permits the 
replicator
to build a more sophisticated decoder. This decoder can read information 
that is encoded
at 10nm resolution. The replicator package has additional information 
encoded at this
resolution, which is a million times denser that the basic replicator,  
This info describes
how to implement more sophisticated substrate technologies. This concept 
is recursive,
so the weight of a self-replicator independent of its sophistication.