A more direct vocal output is the spoken word. Some computers have this capability now, with a modest vocabulary of their own and an extensive tape library to draw from. As an example, Gilfillan Radio has produced a computerized ground-control-approach system that studies the radar return of the aircraft being guided, and “tells” the pilot how to fly the landing. All the human operator does is monitor the show.
The system uses the relatively simple method of selecting the correct words from a previously tape-recorded human voice. More sophisticated systems will be capable of translating code from the computer directly into an audible output. One very obvious advantage of such an automatic landing system is that the computer is never subject to a bad day, nerves, or fright. It will talk the aircraft down calmly and dispassionately, albeit somewhat mechanically.
These then are the five basic parts of a computer or computer system: input, control, arithmetic-logic, memory, and output. Remember that this applies equally to simple and complex machines, and also to computers other than the more generally encountered electronic types. For while the electronic computer is regarded as the most advanced, it is not necessarily the final result of computer development. Let us consider some of the deviants, throwbacks, and mutations of the computer species.
Kearfott Division, General Precision, Inc.
The tiny black box is capable of the same functions as the larger plastic laboratory model pneumatic digital computer.
Packaging densities of more than 2,000 elements per cubic inch are expected.
Another Kind of Computer
We have discussed mechanical, electromechanical, electrical, and electronic computers. There are also those which make use of quite different media for their operation: hydraulics, air pressure, and even hot gases. The pneumatic is simplest to explain, and also has its precedent in the old player-piano mentioned earlier.
Just as an electric or electronic switch can be open or closed, so can a pneumatic valve. The analogy carries much further. Some of the basic electronic components used in computers are diodes, capacitors, inductors, and “flip-flop” circuits which we have talked of. Each of these, it turns out, can be approximated by pneumatic devices.
The pneumatic diode is the simplest component, being merely an orifice or opening through which gas is flowing at or above the speed of sound. Under these conditions, any disturbance in pressure “upstream” of the orifice will move “downstream” through the orifice, but any such happening downstream cannot move upstream. This is analogous to the way an electronic diode works in the computer, a one-way valve effect.
The electrical capacitor with its stored voltage charge plays an important part in computer circuitry. A plenum chamber, or box holding a volume of air, serves as a pneumatic capacitor. Similarly, the effect of an inductor, or coil, is achieved with a long pipe filled with moving air.