5/10    What's the difference between a simulator and an emulator?
        \_ Emulation is along the lines of "perform all the same actions as"
           while simulation is "a system or enviornment where conditions are
           the same." The distinction is highly contextual.  And as you give
           absolutely no context, your question is pretty unanswerable.
              \_ no, it doesn't.
           \_ are there simulators that do not try to "perform all the same
              actions as" the design under simulation?  is non-trivial
              simulation ever performed where "a system or environment where
              conditions are the same"?
              \_ Don't be daft.  Without valid context, this discussion means
                 nothing.  "But those words can be used almost interchangibly!
                 And they might even be SYNONYMS!"  You're beating a dead horse
                 behind chicken coop doors.
              \_ yes.  The Palm OS Simulator is one example.
        \_ Emulator: VirtualPC, VMWare, etc.
           Simulator: VCS, VerilogXL, etc.
        \_ an emulator tries to mimic hardware.
           \_ and a simulator doesn't?  try again.
              \_ No. He means mimic in that the host environment pretends
                 to be capable of what the guest environment is capable
                 of giving an illusion to the user. For example, VirtualPC
                 gives the user an illusion that a Mac is running Windows
                 software. Simulators make no pretense of doing so. For
                 example, VCS is a verilog simulator. It doesn't allow
                 the computer it's running on to mimic the hardware it's
                 simulating.
                 \_ what's the point of running a simulator if it doesn't
                    mimic the hardware it's simulating?  if i give you a
                    black box, how can you tell if there's a simulator or
                    an emulator running underneath?
                    \_ We use an RTL simulator for ASIC design so that
                       we can pass it some test vectors (similar to how
                       things would happen in real life) and view the
                       results in a waveform viewer. Simulators are
                       orders of magnitude slower than a real machine
                       but the purpose is not to have a usable system
                       but something which you can debug through a
                       waveform viewer. The engineers at Intel, for
                       example, are not using RTL simulators to run
                       WindowsXP on a chip that doesn't exist. That
                       would be impractical. They use it to run small
                       bits of code for design verification purposes.
                       \_ ah, an asic "expert".  have you done hardware/
                          software co-design, where the low-level driver
                          and firmware is developed on the hardware simulator?
                          and they call that... co-emulation?  no!  it's
                          called co-sim, son, as in co-simulation.  and just
                          because win-xp is too bloated and modern processors
                          are too large, that doesn't mean that no os has
                          ever been booted in simulation in the history of
                          hardware design and simulation.
                        \_ AMD used to boot NetBSD on Hammer simulations
                           regularly.
                    \_ speed.  a simulator can be faster than an emulator at
                       the expense of accuracy.
                       \_ ah, speed.  so let's say you have an OS running
                          on a cpu and system that is being simulated on
                          a (say) verilog simulator.  are you simulating or
                          emulating the OS?  can a simulator emulate?  can
                          an emulator simulate?
                          \_ I don't think there's always a clear-cut
                             distinction.
              \_ Maybe he means stimulator.  Oh, yeah. That mimics hardware
                 also.