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

Emulator:

Consider a situation that you know only English and you are in China. In order to interact with a Chinese person you need a translator. Now, role of translator is that it will seek input from you in English and convert to Chinese and and give that input to the Chinese person and gets response from the Chinese person and convert to English and give the output to you in English. Now that translator and Chinese person is the emulator. Both combine will provide similar functionality as if you were communicating with the English person. So hardware may be different but functionality will be same.

Simulator:

I can't give better example than SPICE or flight simulator. Both will replace hardware component behavior with the software or mathematical model which will behave similar to the hardware.

In the end it depends on the context that which solution better suits project needs.

Answer 2

Simple Explanation.

If you want to convert your PC (running Windows) into Mac, you can do either of these:

(1) You can simply install a Mac theme on your Windows. So, your PC feels more like Mac, but you can't actually run any Mac programs. (SIMULATION)

(or)

(2) You can program your PC to run like Mac (I'm not sure if this is possible :P ). Now you can even run Mac programs successfully and expect the same output as on Mac. (EMULATION)

In the first case, you can experience Mac, but you can't expect the same output as on Mac.
In the second case, you can expect the same output as on Mac, but still the fact remains that it is only a PC.

Answer 3

Some years ago I came up with a very short adage that, I believe, captures the essence of the difference quite nicely:

A simulator is an emulator on a mission.

By that I mean that you use an emulator when you can't use the real thing, and you use a simulator when you can't use the real thing and you want to find something out about it.

Answer 4

In more or less normal parlance: If your software can do everything the mimicked system can do, it's an emulator. If it only approximates the results of a system (IT or otherwise), it's a simulator.

Answer 5

The definitions of the words describe the difference the best. A google search gives the following definitions of simulate and emulate:

simulate imitate the appearance or character of.

emulate match or surpass (a person or achievement), typically by imitation.

A simulation imitates a system. An emulation simulates a system so well that it could replace it or may even surpass it.

In computing, an emulation would be a drop in replacement for the system it is emulating. Often times it will even outperform the system it is imitating. For example, game console emulators usually make improvements such as greater hardware compatibility, better performance, and improved audio/video quality.

Simulations, on the other hand, are limited by them being models. They are a best attempt to mimic a system, but not replacements for it. There are hardware emulators because hardware can be imitated and it would be hard to tell the difference. There is no Farming Emulator because there is no emulation that could replace actual farming. We can only simulate a model of farming to gain insight on how to farm better.

Answer 6

A Virtual PC tries to emulate a Computer, from the point of view of a Programmer BUT, at the same time, it simulates a Computer from the point of view of a Electrical Engineer.