IN THE BUBBLE JOHN THACKARA - witz cultural

68 Chapter 3
puter world, in which network designers rail against delays measured in
milliseconds, is years ahead of the rest of us in rethinking space-time issues.
Computer network design can teach us how to rethink the real-world
mobility dilemma.
Embedded on microchips, computer operations entail carefully accounting
for the speed of light. A 600-megahertz Pentium II processor, for example,
executes one computing instruction a nanosecond; this is the time
needed for a signal to move nine inches on a metal wire—and a leadingedge
chip today houses as much as seven miles of wires. On the ground,
network delays stem chiefly from the distances between Internet routers.
Across the Internet, the average message flows through seventeen routers,
and sometimes as many as forty. Many of these routers are thousands of
miles—or tens of milliseconds—apart.
The problem the designers are struggling with is called latency—the delay
caused by the time it takes for a remote request to be serviced or for a message
to travel between two processing nodes. Another key word, attenuation,
describes the loss of transmitted signal strength as a result of
interference—a weakening of the signal as it travels farther from its source
(much as the taste of strawberries grown in Spain weakens as they are
trucked to faraway places like Amsterdam).
The inevitability of latency and attenuation prompt serious talk of a
‘‘light-speed crisis’’ in microprocessor design. Optical computing guru
George Gilder, for example, says that ‘‘the chip faces a light speed crisis
that requires a radical change in the time-space relations of processors and
memories. Money will not change it: you can’t bribe God.’’ 44 The only way
to combat the limits of light speed is by moving closer to the data—and
moving the data closer to you. Hence the emphasis now being placed by
network designers on geodesic distance. Gilder describes the Internet as a
‘‘computer on the planet. Like a computer on a mother board, it faces severe
problems of memory access.’’ 45
The search for geometric efficiency now dominates all scales of information
processing and distribution. This search has prompted the emergence
of the storewidth paradigm or ‘‘cache and carry’’—a focus on
copying, replicating, and storing Web pages as close as possible to their
final destination—at so-called content access points. If you go to retrieve a
large software update from an online file library, you are often given a
choice of countries from which to download it. The technique is called