An abstract machine is a theoretical model that allows for a detailed and precise analysis of how a computer system functions.
Abstract machines are
- ”machines” because they allow step-by-step execution of programs;
- “abstract” because they ignore many aspects of actual (hardware) machines.
A typical abstract machine consists of a definition in terms of input, output, and the set of allowable operations used to turn the former into the latter.
One such example is the Turing machine.
See also: Lambda Calculus
Classifications
- Deterministic abstract machines
- For some given allowable operation and some input, it always produces the same output.
- Non-deterministic abstract machines
- Non-deterministic algorithms are helpful for obtaining approximate answers when deriving a precise solution using a deterministic approach is difficult or costly.