Examples of Abstract Machines

Numerous physical situations related to data processing are shown to be modeled by a mathematical entity called a quasi-machine. The situations described include 1) single inputs producing multiple outputs, 2) machines yielding no outputs upon insertion of certain inputs, 3) the retention of the last n outputs only, 4) ``erase left´´ on tape, 5) different input routines doing the same work, and 6) certain types of asynchronous switching circuits. The first five may be modeled by quasi-machines with a special property, such quasi-machines being called abstract machines.