About the ABC Simulation  

A simulation of the ABC is presented here. To successfully use the ABC one must be precise and orderly in the setting of controls and card management. Familiarity with the material in the operator's manual is necessary for manual operation. However, this is alleviated in the simulation by the provision of an auto-mouse (Otto) facility which automatically performs the operations to solve a set of equations.

ABC Simulation
& Suggestions

Physical presentation: The simulation attempts to provide a reasonable facsimile of the front panel, card readers and punch of the ABC. Proportions have been altered for the sake of screen space, but the basic ordering and positioning of items approximates the original.

Algorithms: The algorithms and the functioning of the controls as implemented in the simulation were pieced together from what could be derived from the references. Some 'reverse engineering' conjecture has been employed to fill in the gaps in the references, based on what would have been the probable construction using the then-available switches, relays, etc., and working from the premise that the control system was kept as simple as possible.

One revolution (hence one vector operation) of the ABC drums is an atomic event to the simulator, and this event is deemed to occur at the end of the time occupied by the revolution. None-the-less, the simulator does perform true 50-bit arithmetic, so the numerical results from the simulator should be identical to those of the original ABC. For the proof-of-concept simulation, bit operations are atomic events.

Figure 1: A View of the ABC Simulator Screen

Using the simulation

Figure 1 is a snap of the ABC simulator as the auto-mouse (Otto) proceeds through stage 2 of the solution process, as indicated by the columns of cards in the card bins. A card has been read through the base-2 card reader and Otto is just dropping a card on the base-2 punch.

  Automatic Operation Program
Proof-of-Concept | Architecture | ASM | Manual | Simulation