4 ms·

How are all these VMs going to react if people switch, say, to desktops with ARMv8, or whatever comes next?

by gngeal 13y ago

zimbatm 13y ago
Just use Qemu. It can run a number of CPU and architectures and is cross-platform. Link: http://wiki.qemu.org/Main_Page http://wiki.qemu.org/Main_Page
- limmeau 13y ago
  Pulling the long-time-portability lever one mark further, I suggest Bochs. It's slow because it doesn't use Qemu's dynamic recompilation, but on the other hand, that simplicity makes the job of future archaeologists easier.
lifebeyondfife 13y ago
>Agree with your hypervisor/architecture point but I suppose there has to be some broad architectural choice made. There's a risk that the VM platform decision could date and, ultimately, render useless an experiment sandbox. However, two points. Firstly, any attempt to wholly encapsulate an experiment will be susceptible to problems concerning the technology choices made. By choosing the abstraction at a VM level, you're more likely to get a better number of years out of your choice than picking specific programming languages (which I contend would fail to gain adoption as researchers wouldn't change their obscure toolkit if they felt it was the right one for their research). Secondly, even a VM for an obsolete architecture is better than what we have today - the original paper and perhaps an email address for the lead author.
CJefferson 13y ago
I can emulate a PDP11, a Nintendo Gameboy, or any other old system. There are perfectly functional x86 emulators for ARM already. Many people used to run Windows on PPC macs via emulation too.
- gngeal 13y ago
  Emulating a Gameboy is fine, but emulating a large-scale scientific computation may be just a little bit more demanding, I'm afraid. :/
  - turingfan 13y ago
    In gaming world it seems like it's always hard to emulate the last generation, and quite easy to do ones before that. (E.g. Xbox not emulating their predecessors.) It's not my area of expertise but I expect to see something similar here. If you need to emulate hardware you might take a 10x hit, which might be unacceptable for very large scale computations. But in the longer run that might not be a problem as more resources become available.
  - CJefferson 13y ago
    It will be slower, but I don't think unusable. Actually, comparing gameboy (and other consoles) is not really a good idea, as they are systems where getting all the processors exactly in sync is important and difficult. Emulating a PC is much easier, as no-one expects to get exactly equal speeds out of processors, as every PC model is slightly different. As I say, I (and many other people) emulated x86 windows on PPCs for years. I ran visual studio and it dragged a little, but was fairly usable. Certainly it won't be as fast, but then again by the time x86 has died and people have moved, hopefully systems will have got fast enough to make up the difference!

How are all these VMs going to react if people switch, say, to desktops with ARMv8, or whatever comes next?

by gngeal 13y ago

How are all these VMs going to react if people switch, say, to desktops with ARMv8, or whatever comes next?

Just use Qemu. It can run a number of CPU and architectures and is cross-platform. Link: http://wiki.qemu.org/Main_Page http://wiki.qemu.org/Main_Page

limmeau 13y ago
Pulling the long-time-portability lever one mark further, I suggest Bochs. It's slow because it doesn't use Qemu's dynamic recompilation, but on the other hand, that simplicity makes the job of future archaeologists easier.

lifebeyondfife 13y ago

>Agree with your hypervisor/architecture point but I suppose there has to be some broad architectural choice made. There's a risk that the VM platform decision could date and, ultimately, render useless an experiment sandbox. However, two points. Firstly, any attempt to wholly encapsulate an experiment will be susceptible to problems concerning the technology choices made. By choosing the abstraction at a VM level, you're more likely to get a better number of years out of your choice than picking specific programming languages (which I contend would fail to gain adoption as researchers wouldn't change their obscure toolkit if they felt it was the right one for their research). Secondly, even a VM for an obsolete architecture is better than what we have today - the original paper and perhaps an email address for the lead author.

CJefferson 13y ago

I can emulate a PDP11, a Nintendo Gameboy, or any other old system. There are perfectly functional x86 emulators for ARM already. Many people used to run Windows on PPC macs via emulation too.

gngeal 13y ago
Emulating a Gameboy is fine, but emulating a large-scale scientific computation may be just a little bit more demanding, I'm afraid. :/
- turingfan 13y ago
  In gaming world it seems like it's always hard to emulate the last generation, and quite easy to do ones before that. (E.g. Xbox not emulating their predecessors.) It's not my area of expertise but I expect to see something similar here. If you need to emulate hardware you might take a 10x hit, which might be unacceptable for very large scale computations. But in the longer run that might not be a problem as more resources become available.
- CJefferson 13y ago
  It will be slower, but I don't think unusable. Actually, comparing gameboy (and other consoles) is not really a good idea, as they are systems where getting all the processors exactly in sync is important and difficult. Emulating a PC is much easier, as no-one expects to get exactly equal speeds out of processors, as every PC model is slightly different. As I say, I (and many other people) emulated x86 windows on PPCs for years. I ran visual studio and it dragged a little, but was fairly usable. Certainly it won't be as fast, but then again by the time x86 has died and people have moved, hopefully systems will have got fast enough to make up the difference!