🚀 go-pugleaf

I have been reading about nanotech in _Foresight Update_  in _EOC_, and a 
few other places.  Maybe someone can answer (or tell me no answer exists 
to) the following questions:

1. Drexler makes the assemblers sound like a miniature robot with an 
arm to which is attached a molecule or an atom to be placed at a specific 
point. The mechanism proposed is "selective stickiness", but this does'nt 
sound any more usefull than chemistry. Is it?

[I'll break my usual rule and answer these questions in-line:
 Atoms can be "stuck" with forces ranging from covalent bonds to 
 van der Waals forces, with a difference in strength on the order
 of 100.  The most desirable method would seem to be to "pick up"
 the reagent molecule with a van der Waals bond and have it have
 it latch onto the object you're building by a covalent bond, 
 allowing you simply to pull the arm away and break the vdW bond
 by force.  Alternatively, you might alter the geometry of the
 "gripper" to expel the reagent.
 Chemistry is like building a gadget of Lego blocks by alternately
 pouring piles of the various different kinds of blocks over the 
 object.  The trouble is they will stick everywhere it is possible
 for them to stick.  Nanotechnology (like protein synthesis in
 the cell) is supposed to be a way to control which of the possible
 sites, a reaction actually happens at.]

2. Recent articles in _Foresight Update_ speculate about incredibly 
powerfull computer systems possible in an advanced nanotech society. I 
guess these speculations are based on the size and speed of imagined 
mechanical/molecular gate operations. Has anybody guessed what the 
difficulty would be of making  mechanical gate ops interconnected, and 
how these gate ops would be powered?

[As a computer architecture person myself, I've looked at it.
 The connectivity isn't a problem--remember that existing computers
 are basically planar; if you allow yourself 3 dimensions it's
 a lot easier.  Power is a bit more out of my field, but suggestions
 tend to run to electrostatic motors of some kind.
 No one, by the way, seriously expects that nanocomputers will be
 actually built this way.  Drexler holds them up as existence proofs;
 real nanocomputers will probably use highly involved quantum effects
 and run at speeds of about 100 terahertz instead of the roughly one
 megahertz the mechanical design could do.]

3. The closest thing to a nanomachine I've ever heard of is a virus. Has 
there been any attempt to alter an existing virus for a purpose?

[No and yes.  An assembler is not like a virus, since the virus 
 requires an outside self-reproducing mechanism to work;  to get
 going in nanotechnology you need to produce the self-reproducing
 mechanism itself.
 On the other hand, a virus might be like some specialized end-product
 of a different and larger nanotechnological base.  
 And yes, retroviruses have been used to insert missing genes into
 organisms (I think, including humans).]

In regards to discussions about cryonics on this newsgroup:

In a technology advanced enough to literally raise you from the dead 
(frozen), I think the new limitation imposed on that society would simply 
be raw material. What will the motivation be for that future society to 
recover you?  What will you offer?  Should you sign an agreement before 
you die stating that you will abide by the laws of that future society?

One final statement.

If the promise of nanotech/AI becomes even partially true then it might be 
possible to subtly, yet directly alter mental state by altering synaptic 
wieghts and other aspects of brain function.  

I will wait for your responses before continuing.