From WikiChip
analog computer

An analog computer is a computer that represents problem variables as continuous varying physical quantities and has an internal structure that is modified to fit the physical model at hand. This is in contrast with digital computers where problem variables are represented symbolically and has a fixed internal structure in which data flows through.

Analog computers follow a drastically different paradigm to that used in digital computers. Unlike digital computers which have a fixed internal structure composed of a number of units that perform various operations depending on what's instructed of them, analog computer's structure changes by its user depending on the problem attempting to be solved - i.e. an analog computer solves problems by simulating analogical models that were designed through rearrangement of the computer's structure. Such rearrangement or programming is usually done through a convenient patch panel.