(4) Integrated circuit. The term "integrated" derives from the fact that the
entire circuit with all its component parts (transistor, resistor, and so forth) is etched
simultaneously on the same piece of semiconductor material (usually silicon). Chips
represent a vast improvement over second generation transistors that were hand-wired
and -soldered together to form bulky circuits. Chips save space, do away with the time-
consuming need for wiring components together, and increase reliability by minimizing
Figure 3-17. A microprocessor on a chip, the building block of modern computers,
is tied to electrical contact points by gold wires finer than human hair.
d. The Computer on a Chip. The computer on a chip or microcomputer was
made possible by miniaturization and the low price of chips (only six dollars in 1975).
By 1975, the special functions of a variety of chips were combined to create a computer
on a single device. The microprocessor chip, the nerve center, is the generalist that
runs the whole computer. Other chips, serving at least a half-dozen separate functions,
are like specialists serving single functions (like RAM, read and write memory). The
cameras, watches, automobile dashboards, home appliances, telephones, and juke
boxes. The microchips inside cameras, cars, watches and specialists are each
programmed to carry out a limited set of tasks. Microcomputers also contain single-
function chips like those in cameras with built-in instructions for running certain parts of
the machine. But the generalist microprocessor is the microchip that enables a home
computer, for example, to switch from playing an exciting video game that simulates
sports, to rearranging the paragraphs in a business report.