I’m guessing the answer is ‘no’, but I’m curious to verify that.
If you build a simulation, and one of the things that happens in the simulation is you build a computer (like the minecraftcomputers built inside the game) is there any way for the computer to be faster than the host computer?
I’m guessing a simulated computer can’t use quantum effects which would in theory make it faster than a classical computer simulating it. ie, a good enough quantum computer should be faster than any classical computer possible in the universe. But I doubt quantum effects would exist within software that could be used to build it.
The simulated computer might be able to solve a particular task faster than another specific algorithm running without the simulated computer.
The simulated computer could not solve a task faster than ALL possible algorithms on the host computer, because one of the algorithms is “First, build a simulated computer in the following specifications…” and so on. That is a path for the host computer to solving the problem.
It is possible that an application running inside a virtual computer might be faster than the same application running on the host computer.
This because applications run inside the Operating System, which is a kind of virtual computer anyway (windows 98 system explicitly presented a virtual computer, others only implicitly).
And Operating Systems are optimised for particular kinds of loads, and an imtermediate virtual computer can be optimised differently, both up towards the application, and down towards the host.
This is unlikely at present, but it’s not impossible: it used to be a sad-but-true fact of some mainframe systems. That some particular classes of applications ran better inside a virtualised environment than they did running on the host.
That may be true to the extent that some OSs may be spectacularly inefficient for certain kinds of applications, but it’s really a bit of a nitpick. I suspect the OP is asking the question at a more theoretical, fundamental level. The only really meaningful general interpretation of that question is whether a simulated computer of the same architecture can be faster than the host, otherwise the question has no useful meaning. And the answer is “no”.
As a side note, there are really two different approaches to creating a “computer within a computer”. One is a virtual machine, which is not really a simulation at all, but a special protected mode in which normal instructions execute on the physical hardware but all interactions with the outside world are trapped by the hardware and mediated by the VM software. Thus you can have multiple and diverse operating systems installed and all running at the same time on one physical machine. Such a machine can theoretically run as fast as the host for computationally bound operations, and that’s about the best you can do. Certain applications might actually run better on the VM as noted, say under a simpler OS with less overhead, but as I said that’s a bit of a nitpick.
Running an actual simulation of the same architecture would be a silly way to do anything practical since it would be far slower. But the interesting thing is that computers have increased in speed so rapidly over the years that simulations of older computer architectures typically run on PCs nowadays much, much faster than the original. I have a PDP-10 simulator that is far faster than the original hardware, so I can play a really cool chess game with it and get far faster response at better play levels than the real machine could ever achieve, even though the original machines cost several million dollars and required a massive computer room, power, and A/C!
If in the general case the simulated computer were faster, the first thing I would do is run the simulation software on it, and run another computer simulated computer inside that simulator. Rinse and repeat. Clearly, eventually I would get an arbitrarily fast computer for free. This sounds like a really neat idea.
If your simulation was of a quantum computer, you need to explicitly keep the entire vector of probabilities for each qbit, and for each operation maintain these vectors. You don’t win. The entire point of quantum computer is that the potential speed-up comes from this state evolving in parallel without needing any additional computation. If your simulation is some quantum computer simulating another computer, see the first point.
You might be able to get a faster clock speed on the simulated computer, but clock speed is a lousy way of measuring computer performance to begin with.
You don’t need to go back nearly that far for a simulation to be faster. I’ve got an HP 48 emulator on my phone that runs significantly faster than the original ever did, and that’s a good 2-3 decades more recent than a PDP-10.
Certainly. It’s just that the PDP-10 (aka DECsystem-10 in later years) was a landmark computer both in timesharing and in pioneering achievements in AI, so it’s kind of cool (and also nostalgic) being able to run some of those early AI programs right on my PC, the MacHack chess program being particularly historic, and still lots of fun to play because it’s rather creatively aggressive.
The PDP-10 was of course a timesharing system, so theoretically, as it runs so much faster than the original hardware, I could use it to support hundreds of traditional dumb-terminal timesharing users on my desktop PC. Pretty impressive considering that Windows can barely manage to efficiently timeslice a handful of processes on hardware with three orders of magnitude more speed and memory!
Yeah. This is sort of a generalized version of the pigeonhole principle for compression algorithms. You can compress many classes of data, but you can’t compress all things, and the overall compression ratio must be less than 1.
Bytecode languages like Java are running on a simulated computer of sorts, and they can in principle be faster at some problems, because they can recompile the code at runtime to take dynamic factors into account. This is pretty rare, though.
If you had a bunch of simulations running at once, you could potentially exploit redundancy for some savings. If you wanted to simulate a million different Earths starting at, say, 250k years ago, you could get away with only having one simulation of the rest the universe outside of a 250k light-year sphere. Additional simulations would be basically free since Earth’s light cone is so tiny compared to the rest of the universe.
Basically, it’s possible for a computer to simulate a less powerful computer, while being more powerful than what it’s simulating.
First we need to draw a distinction between emulation and simulation. The former is the far more common approach. Emulation means being able to run software for another system and achieve the same output, even if you fudge the details of how you get there. The easiest way to emulate yourself is just to do what you do normally.
Simulation is harder, because it requires keeping a faithful model of all the physical stuff. There are, of course, various layers of abstraction, but building a computer in Minecraft is basically simulating the circuits down to the logic gates which is getting pretty close to the lowest level you can reasonably simulate before you get into hardcore supercomputer-needing physics calculations.
Emulation frequently requires some steps of low-level simulation to present faithful results, when the hardware you’re emulating is sufficiently different from the host computer, but a lot of it is approximate fudging or other tricks like directly translating machine code where possible. (Of course, the other option is to port the program, which can sort of be called emulation in a broad, labor-intensive sense)
The only real scenario in which you can run a simulated computer faster than a real computer is when the simulated computer is slower than the number of steps it takes to update all your simulated hardware. If the computer you’re simulating is yourself, well, obviously you might as well just run the program.
As mentioned, there may be corner cases where you could simulate yourself running different software that executes the same program faster than your host OS, and it may be faster depending on some virtualization quirks, but in the general case this isn’t possible.
If you are running the same set of operations in the simulation as on the hardware, it can’t possibly be faster. The simulation has the overhead of simulating in addition to the operations themselves, and the simulation itself has to be run on the hardware.
Put it another way.
Programs are compiled to machine code. (Assembly language instructions are the human-readable version of machine code.) If you simulate a processor which executes assembler instructions, it can only perform that by executing similar assembler instructions on the host hardware chip. Therefore it must be slower. QED.
