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• ... Gina, I ve always used 1 Library of Congress (LOC) ~ 40 million volumes x 150,000 words/volume x 6 bytes/word x 8 bits/byte ~ 3 x 10^14 bits. Philip
Message 1 of 5 , Feb 14, 2000
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> From: "Gina Miller" <nanogirl@...>
> David,
> My estimates come from Rob Freitas:
> http://www.foresight.org/Nanomedicine/NanoMedFAQ.html#FAQ19
>Consider that a nanostructured data storage device measuring ~8,000
>micron3, a cubic volume about the size of a single human liver cell
>and smaller than a typical neuron,
>could store an amount of information equivalent to the entire
>Library of Congress. If implanted somewhere in the human brain,
>together with the appropriate interface
>information.

Gina, I've always used 1 Library of Congress (LOC) ~ 40 million volumes x 150,000 words/volume x 6 bytes/word x 8 bits/byte ~ 3 x 10^14 bits. Philip Morrison [SciAm(July98):115] claims the 1998 LOC has only 20 million volumes but that there are also ~2 x 10^15 bits of sound recordings -- assume 10:1 data compression of the sound for nano-storage, and our total LOC figures agree. Or make your own estimate. Below, I'll use mine.

Assuming fluorocarbon tape information density of ~26 bits/nm^3 [NMI:178], 1 LOC can be stored in ~12,000 micron^3 (~one large-ish human liver cell volume). Using Drexler's slightly more conservative ~5 bits/nm^3 for tape storage [NS:366], 1 LOC can be stored in 60,000 micron^3 (~one very fat macrophage cell volume).

Assuming rod logic register storage with information storage density of ~0.025 bits/nm^3 [NS:357], 1 LOC requires a storage volume of 0.012 mm^3, a cube ~230 microns on an edge.

>>A single nanocomputer CPU, also having the volume of just one tiny
>>human cell, could compute at the rate of 10 teraflops (1013
>>floating-point operations per second),
>>approximately equalling (by many estimates) the computational output
>>of the entire human brain.

> On page 370 of Nanosystems, Drexler talks about a 10^15 MIPS (roughly
> 10^21 operations per second) machine with water cooling as being a
> cubic cm in volume. Merkle estimates the computational power of the
> human brain as "It seems reasonable to conclude that the human brain
> has a raw computational power between 10^13 and 10^16 operations per second."
> (http://www.merkle.com/brainLimits.html)
> Thus the 1 cubic cm computer is roughly a megabrain computer.
> Since 1 cubic cm is 10^12 cubic microns, there is one brain per 10^6
> cubic microns. Using an estimate of 10^4 cubic microns for a larger
> human cell, that would be one brain per 100 cells. Thus there is a
> difference of 100 between Drexler and Freitas, probably because
> Freitas is using less conservative assumptions, or assuming molecular
> electronics, etc.

Drexler's 10^15 MIPS/cm^3 figure [NS:370] equals 10 teraflops per 10,000-micron^3 (mammalian cell size) volume. Ten teraflops is simply Merkle's lower 10^13 ops/sec brain-capacity figure. If instead you use Merkle's upper 10^16 ops/sec brain-capacity figure, then you need 1000 tissue-cell volumes, a cube ~200 microns on an edge, roughly the size of a human ovum (also a mammalian single cell). Take your pick. AFAIK, there is no "difference of 100" involved; our assumptions are identical.

Robert A. Freitas Jr.
• ... Gina: raw computing power is a meaningless metric in that context. You re guaranteed to be misunderstood here, which is probably not what you want. Apart
Message 2 of 5 , Feb 14, 2000
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David Forrest writes:

> "Nano-theorists have estimated that the entire contents of the Library of
> Congress could be stored in a
> nanocomputer the size of a human cell, and that another nanocomputer the
> size of a human cell could have the same raw
> computing power as the whole human brain. "

Gina: "raw computing power" is a meaningless metric in that
context. You're guaranteed to be misunderstood here, which is probably
not what you want. Apart from that, estimates on how many OPS the
brain actually does are 1) notoriously unreliable ad hoc numbers 2) in
my estimates several orders of magnitude too low
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