Matthew Hutson, English 111, Brown University (1998)
With an understanding of how analog and digital information is stored, we can discuss how it's processed, namely in computers. Analog computing machines contrast the digital kind we are familiar with in a most basic, even quaint, way. Rather than handling little anonymous blips of data that fly around from silicon chip to silicon chip, their guts involve somewhat more tangible parts: transistors, resistors, and capacitors (which build in charge in a continuous, graphable way), or vacuum tubes, or even mechanistic parts. The Boston Computer Museum has a mechanical analog computing device for handling simple arithmetic constructed completely out of TinkerToys.
Digital computers process information as tables, lists, and finite samples of data, while analogue machines model actual (continuous) functions. Working best as tailored processors for specific problems, each component of an analogue computer simulates some portion of the physical problem at hand. They can also solve abstract mathematical problems isolated from any particular situation, provided the functions can be physically modeled by the relatively mechanistic parts of the analogue processor. Thus the circuitry and internal parts of the machine can directly emulate physical reality, a feat only approximated by the lists of bits within a digital processor. Paul Von Handel describes in his book, Electronic Computers (published in 1961):
[An analog computer] is not the instrument to look for if high-precision computations are required. But it is certainly preferable if the engineer or physicist looks for an instrument which not only gives a formalistic answer to the questions he asks but which provides a physical entirety, intimately related to his problem. It allows the study of every detail of his problem under any desired configurations in a direct, experimental way.
Analog tools sometimes give a truer, more natural representation of phenomena, especially physical systems. Every nuance of the input affects the output, so the system and the model (the analog computer) share a kind of intimacy that one cannot achieve with digital processing. Digital computers sometimes can feel cold, impersonal, or artificial, but because digital information is somewhat distanced from analog reality, we can use it to construct previously unimaginable abstractions.