Concurrency, was Re: Doh! Stupid Programming Mistakes <humor>

Steve smorrey at gmail.com
Fri Oct 27 11:54:57 MDT 2006


<snip>
> I believe that OSes and computing systems will be designed to hide this
> fact from the programs, allowing normal programs to be spread
> dynamically across nodes.  Maybe through some system that emulates
> shared memory and local devices (mapping remote ones).  Even in a system
> that emulates shared memory (say by swapping pages of memory across
> nodes), your threads may think they are not copying memory (accessing it
> directly) but are not.
</snip>

Is this describing OpenMosix?

On 10/27/06, Michael L Torrie <torriem at chem.byu.edu> wrote:
> On Fri, 2006-10-27 at 08:55 -0600, Shane Hathaway wrote:
> > Your argument for threads is retarded.  You're still assuming that you
> > actually have control over the scope of all variables, but future
> > maintainers will simply add the "static" keyword to one of your
> > variables, breaking your model.  This is no fantasy; I've seen bright
> > programmers do just that.  Or someone like me will come along and try
> > very hard to understand your model, but then extend your model in a way
> > that introduces subtle but nasty bugs.  And it will cost a whole lot to
> > fix the mess.
> >
> > Look at the rise of web services.  Web services are little more than IPC
> > across multiple machines.  Apparently people find value in the concept.
> >   I'm sorry you don't.
> >
> > Now, don't forget this is a humor thread.  This argument is for fun; in
> > reality, you're exactly right WRT some kinds of problems.
>
> Besides all this, computing is evolving to be distributed nowadays, with
> a non-unified memory architecture.  Nodes do not share memory; they
> communicate with a protocol.  There's a reason why in super-computing
> MPI and other message-passing protocol schemes are king.  Threads
> obviously don't make sense in any kind of distributed architecture.  Now
> I believe that OSes and computing systems will be designed to hide this
> fact from the programs, allowing normal programs to be spread
> dynamically across nodes.  Maybe through some system that emulates
> shared memory and local devices (mapping remote ones).  Even in a system
> that emulates shared memory (say by swapping pages of memory across
> nodes), your threads may think they are not copying memory (accessing it
> directly) but are not.  Besides that fact, I think it's probably a bad
> idea to code with any particular assumptions about the underlying
> machine architecture (vm or not).
>
> Michael
>
>
>
>
> >
> > Shane
> >
> >
> > /*
> > PLUG: http://plug.org, #utah on irc.freenode.net
> > Unsubscribe: http://plug.org/mailman/options/plug
> > Don't fear the penguin.
> > */
> >
>
>
> /*
> PLUG: http://plug.org, #utah on irc.freenode.net
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>



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