Simulator or Emulator? What is the difference?

Question

While I understand what simulation and emulation mean in general, I almost always get confused about them. Assume that I create a piece of software that mimics existing hard

Answer 1

It's a difference in focus. Emulators¹ focus on recreating the behavior of a system, with no regard for how the system functions internally. Simulators² focus on modeling the components of a system. You use an emulator when you care mostly about what a system does, and a simulator when you care about how it does it.

As for their general English meanings, emulation is "the endeavor to equal or to excel another in qualities or actions", while simulation is "to model, replicate, duplicate the behavior, appearance or properties of". Not much difference. Emulation comes from æmulus, "striving, rivaling," and is related to "imitate" and "image," which suggests a surface-lever resemblance. "Simulation" comes from similis "like", as does the word "similar," which perhaps suggests a deeper congruence.

References:

1. Wikipedia: Emulator
2. Wikipedia: Computer Simulation
3. Wiktionary: emulation
4. Wiktionary: simulation
5. Etymology Online: emulation
6. Etymology Online: simulation