What are the primary differences between a testbed and a simulator?

Question

Apologies for the slightly vague title. Im having trouble discerning the difference between the two. For instance, more often than not when I see simulation(of Real Time Systems) I notice many who modify the linux kernels (2.6.xx the exact one eludes me). Then I see other software that are written in C++, Ada, and whatnot that don't modify any kernels but also do simulation of real time systems.

Then I come across the term testbed. Is that not a form of a simulator also? How are they similar and how are they not alike?

Answer 1

I recommend you do some research. For instance,

• http://en.wikipedia.org/wiki/Testbed
• http://en.wikipedia.org/wiki/Simulator

Basically a testbed is a testing system that can exercise (stimulate) another system with certain inputs (actions, etc) and compare that system's outputs with expected outputs. A simulator is a system that simulates the behavior of another system. For instance, a flight simulator is a device that simulates the flight of an aircraft.

As a result, you could say that a testbed is a system that "simulates" user input but this would not be accurate: it may stimulate (note stimulate not simulate) a system with inputs, but it doesn't pretend to be the user or attempt to predict what the user will do next, rather it simply takes the outputs and compares them to expected outputs.

Answer 2

Testbed = a real-life system that can execute tasks and returns results.

Simulator = an approximate imitation of the execution of task, not actual execution.