Messages in this thread | | | Subject | Re: Scaling noise | From | (Eric W. Biederman) | Date | 08 Sep 2003 02:32:03 -0600 |
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Larry McVoy <lm@bitmover.com> writes:
> On Sun, Sep 07, 2003 at 09:47:58PM -0700, Stephen Satchell wrote: > > At 05:57 PM 9/7/2003 -0700, Larry McVoy wrote: > > >That's not "a machine" that's ~1150 machines on a network. This business > > >of describing a bunch of boxes on a network as "a machine" is nonsense. > > > > Then you haven't been keeping up with Open-source projects, or the > > literature. > > Err, I'm in that literature, dig a little, you'll find me. I'm quite > familiar with clustering technology. While it is great that people are > wiring up lots of machines and running MPI or whatever on them, they've > been doing that for decades. It's only a recent thing that they started > calling that "a machine". That's marketing, and it's fine marketing, > but a bunch of machines, a network, and a library does not a machine make.
Oh so you need cache coherency to make it a machine. That being the only difference between that and a NUMA box.
Although I will state that there is a lot more that goes into such a system than a network, and a library. At least there is a lot more that goes into the manageable version of one.
> Not to me it doesn't. I want to be able to exec a proces and have it land > anywhere on the "machine", any CPU, I want controlling tty semantics, > if I have 2300 processes in one process group then when I hit ^Z they > had all better stop. Etc.
Oh wait none of that comes with cache coherency. So the difference cannot be cache coherency.
> A collection of machines that work together is called a network of > machines, it's not one machine, it's a bunch of them. There's nothing > wrong with getting a lot of use out of a pile of networked machines, > it's a great thing. But it's no more a machine than the internet is > a machine.
Cool so the SGI Ultrix is not a machine. Nor is the SMP box over in my lab. They are separate machines wired together with a network, and so I better start calling them a network of machines.
As far as I can tell which pile of hardware to call a machine is a difference that makes no difference. Marketing as you put it.
The only practical difference would seem to be what kind of problems you think are worth solving for a collection of hardware. By calling it a single machine I am saying I think it is worth solving the single system image problem. By refusing to call it a machine you seem to think it is a class of hardware which is not worth paying attention to.
I do think it is a class of hardware that is worth solving the hard problems for. And I will continue to call that pile of hardware a machine until I give up on that.
I admit the hard problems have not yet been solved but the solutions are coming.
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