ubuntu desktop 12.04 lts on nehalem workstation

[Roger Miller]

Liam,

Thanks for the reply.  Seems like it could be a great box, but we got if
for a single purpose and right now it isn't fulfilling its purpose.

It is the 64-bit version.  uname -a output is:

Linux lincoln 3.2.0-23-generic #36-Ubuntu SMP Tue Apr 10 20:39:51 UTC
2012 x86_64 x86_64 GNU/Linux

Roger

On Tue, 2012-08-14 at 18:16 +0100, Liam Proven wrote:
> On 14 August 2012 17:05, Roger Miller <abq at lwasf.com> wrote:
> >
> > I recently installed ubuntu desktop 12.04 LTS on a workstation equipped
> > with 12 GB of RAM and 2 Xeon 5600-series processors, each with 6 cores.
> > This may not be the kind of equipment that the software was designed
> > for, but I was in a pinch for time.
> 
> Sounds like a great box. I suppose you could run OpenSUSE to soak up
> some more of those spare resources ;¬) but otherwise I see no problem.
> 
> > I am doing groundwater simulations using a widely used and very stable
> > FORTRAN code (MODFLOW-2000).  The code compiles with or without MPI
> > support (using either openMPI or mpich2) and reports no problems.  The
> > simulations fail, reporting impossible problems that suggest to me that
> > the memory is being accessed incorrectly.
> >
> > The same code compiled on an older computer runs on the workstation
> > without problems as long as I am not using MPI.  When I try to run the
> > simulation on more than one core simultaneously I get the same problems
> > reported in the previous paragraph.
> >
> > I have not found any reports of problems with Linux (ubuntu or other)
> > running on Nehalem workstations.  Are there known problems that I have
> > overlooked?  Is there anything I can do to get a clearer picture of the
> > problem?
> 
> I have to ask the silly, obvious question:
> 
> Are you using the 64-bit or 32-bit edition?
> 
> Both will recognise the memory, but I would anticipate problems with
> the 32-bit system trying to manipulate large datasets. The 32-bit
> version uses PAE to access > ~3½ gig of RAM and this works by paging
> small chunks of the RAM above 4GB into address space under 3½GB. That
> will cause problems for you, I think.
> 
> 
> -- 
> Liam Proven • Profile: http://lproven.livejournal.com/profile
> Email: lproven at cix.co.uk • GMail/G+/Twitter/Flickr/Facebook: lproven
> MSN: lproven at hotmail.com • Skype/AIM/Yahoo/LinkedIn: liamproven
> Tel: +44 20-8685-0498 • Cell: +44 7939-087884
>