We have had 'information machines' for many years before computers were common. Among the most common such machines are traditional watches and clocks. These machines are used to measure time, an abstract numerical. They use purely mechanical means to represent information. A tiny motor controls gears which manipulate the hands. The only reason the position of the hands has any informational meaning is because we are trained to interpret it as such. This type of information handling device is referred to as an analog device. The term 'analog' is used because we use an analogy to describe the data. In the case of the watch, we actually have several analogies working at once. The motion of the second hand is analogous to the passage of seconds in a minute. The motion of the minute hand around the dial is an analogy to minutes in an hour, and the hour hand represents hours in a half-day. The process of learning how to read an analog watch comes down to understanding the analogies and what they represent. We have encountered many other analog devices: Dial and liquid thermometers are good examples, so are any of the dials on your dashboard such as the speedometer and fuel gauge. A slide rule is analog. Record players (remember those?) use analog technology. Nearly any display which features a needle or a dial uses analog technology.
Analog information is mechanical. It usually offers nearly infinite precision, but limited accuracy. Here is an example: The dial thermometer outside Joyce's apartment registers 74 degrees F. By looking at the back of the thermometer, she sees it is simply a coil of some sort of metal. When the temperature changes, the metal expands and contracts. The needle is attached to the outside of the coil, so when the length of the coil changes due to a change in temperature, the location of the needle on the dial changes. If she looks carefully enough, (perhaps with a magnifying glass!) she will see the dial fluctuate even with the most minor changes in temperature. As the temperature changes from 50 degrees to 74 degrees, the dial will touch EVERY single intermediate spot in that interval. There is a continuous motion with no jumps or gaps. This is an example of the precision of analog instruments.
At the same time, Joyce recognizes that the accuracy of this device may be suspect. By squeezing the coil, she can change the apparent temperature reading. She can only assume that nobody has changed the shape of the coil manually, thus changing the accuracy of the reading. She also has to trust that the dial was calibrated properly at the factory. If the painting machine were a bit off, or the coil was installed improperly, the machine would not show the proper reading. This problem of accuracy is very common with analog information devices.