in three dimensions
, which I discuss in the next chapter.
We might ask whether there are inherent limits to the capacity of matter and energy to support computational
processes. This is an important issue, but as we will see in the next chapter, we won't approach those limits until late in
this century. It is important to distinguish between the S-curve that is characteristic of any specific technological
paradigm and the continuing exponential growth that is characteristic of the ongoing evolutionary process within a
broad area of technology, such as computation. Specific paradigms, such as Moore's Law, do ultimately reach levels at
which exponential growth is no longer feasible. But the growth of computation supersedes any of its underlying
paradigms and is for present purposes an ongoing exponential.
In accordance with the law of accelerating returns, paradigm shift (also called innovation) turns the S-curve of any
specific paradigm into a continuing exponential. A new paradigm, such as three-dimensional circuits, takes over when
the old paradigm approaches its natural limit, which has already happened at least four times in the history of
computation. In such nonhuman species as apes, the mastery of a tool-making or -using skill by each animal is
characterized by an S-shaped learning curve that ends abruptly; human-created technology, in contrast, has followed
an exponential pattern of growth and acceleration since its inception.
DNA Sequencing, Memory, Communications, the Internet, and Miniaturization
Civilization advances by extending the number of important operations which we can perform
without thinking about them.
—A
LFRED
N
ORTH
W
HITEHEAD
,
1911
42
Things are more like they are now than they ever were before.
—D
WIGHT
D.
E
ISENHOWER
The law of accelerating returns applies to all of technology, indeed to any evolutionary process. It can be charted with
remarkable precision in information-based technologies because we have well-defined indexes (for example,
calculations per second per dollar, or calculations per second per gram) to measure them. There are a great many
examples of the exponential growth A implied by the law of accelerating returns, in areas as varied as electronics of all
kinds, DNA sequencing, communications, brain scanning, brain reverse engineering, the size and scope of human
knowledge, and the rapidly shrinking size of technology. The latter trend is directly related to the emergence of
nanotechnology.
The future GNR (Genetics, Nanotechnology, Robotics) age (see chapter 5) will come about not from the
exponential explosion of computation alone but rather from the interplay and myriad synergies that will result from
multiple intertwined technological advances. As every point on the exponential-growth curves underlying this panoply
of technologies represents an intense human drama of innovation and competition, we must consider it remarkable that
these chaotic processes result in such smooth and predictable exponential trends. This is not a coincidence but is an
inherent feature of evolutionary processes.
When the human-genome scan got under way in 1990 critics pointed out that given the speed with which the
genome could then be scanned, it would take thousands of years to finish the project. Yet the fifteen-year project was
completed slightly ahead of schedule, with a first draft in 2003.
43
The cost of DNA sequencing came down from about
ten dollars per base pair in 1990 to a couple of pennies in 2004 and is rapidly continuing to fall (see the figure
below).
44
There has been smooth exponential growth in the amount of DNA sequence data that has been collected (see the
figure below).
45
A dramatic recent example of this improving capacity was the sequencing of the SARS virus, which
took only thirty-one days from the identification of the virus, compared to more than fifteen years for the HIV virus.
46
Of course, we expect to see exponential growth in electronic memories such as RAM. But note how the trend on
this logarithmic graph (below) proceeds smoothly through different technology paradigms: vacuum tube to discrete
transistor to integrated circuit.
47
However, growth in the price-performance of magnetic (disk-drive) memory is not a result of Moore's Law. This
exponential trend reflects the squeezing of data onto a magnetic substrate, rather than transistors onto an integrated
circuit, a completely different technical challenge pursued by different engineers and different companies.
48
Exponential growth in communications technology (measures for communicating information; see the figure
below) has for many years been even more explosive than in processing or memory measures of computation and is no
less significant in its implications. Again, this progression involves far more than just shrinking transistors on an
integrated circuit but includes accelerating advances in fiber optics, optical switching, electromagnetic technologies,
and other factors.
49
We are currently moving away from the tangle of wires in our cities and in our daily lives through wireless
communication, the power of which is doubling every ten to eleven months (see the figure below).
The figures below show the overall growth of the Internet based on the number of hosts (Web-server computers).
These two charts plot the same data, but one is on a logarithmic axis and the other is linear. As has been discussed,
while technology progresses exponentially, we experience it in the linear domain. From the perspective of most
observers, nothing was happening in this area until the mid-1990s, when seemingly out of nowhere the World Wide
Web and e-mail exploded into view. But the emergence of the Internet into a worldwide phenomenon was readily
predictable by examining exponential trend data in the early 1980s from the ARPANET, predecessor to the Intemet.
50
This figure shows the same data on a linear scale.
51
In addition to servers, the actual data traffic on the Internet has also doubled every year.
52
To accommodate this exponential growth, the data transmission speed of the Internet backbone (as represented by
the fastest announced backbone communication channels actually used for the Internet) has itself grown exponentially.
Note that in the figure "Internet Backbone Bandwidth" below, we can actually see the progression of S-curves: the
acceleration fostered by a new paradigm, followed by a leveling off as the paradigm runs out of steam, followed by
renewed acceleration through paradigm shift.
53
Another trend that will have profound implications for the twenty-first century is the pervasive movement toward
miniaturization. The key feature sizes of a broad range of technologies, both electronic and mechanical, are
decreasing, and at an exponential rate. At present, we are shrinking technology by a factor of about four per linear
dimension per decade. This miniaturization is a driving force behind Moore's Law, but it's also reflected in the size of
all electronic systems—for example, magnetic storage. We also see this decrease in the size of mechanical devices, as
the figure on the size of mechanical devices illustrates.
54
As the salient feature size of a wide range of technologies moves inexorably closer to the multi-nanometer range
(less than one hundred nanometers—billionths of a meter), it has been accompanied by a rapidly growing interest in
nanotechnology. Nanotechnology science citations have been increasing significantly over the past decade, as noted in
the figure below.
55
We see the same phenomenon in nanotechnology-related patents (below).
56
As we will explore in chapter 5, the genetics (or biotechnology) revolution is bringing the information revolution,
with its exponentially increasing capacity and price-performance, to the field of biology. Similarly, the
nanotechnology revolution will bring the rapidly increasing mastery of information to materials and mechanical
systems. The robotics (or "strong AI") revolution involves the reverse engineering of the human brain, which means
coming to understand human intelligence in information terms and then combining the resulting insights with
increasingly powerful computational platforms. Thus, all three of the overlapping transformations—genetics,
nanotechnology, and robotics—that will dominate the first half of this century represent different facets of the
information revolution.
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