[R] Memory Management under Linux: Problems to allocate large amounts of data

[Dubravko Dolic]

Dear Peter,

AMD64 and EM64T (Intel) were designed as 32bit CPUs which are able to address 64bit registers. So they are nut "pure" 64bit Systems. This is why they are much cheaper than a real 64bit machine.

-----Ursprüngliche Nachricht-----
Von: pd at pubhealth.ku.dk [mailto:pd at pubhealth.ku.dk] Im Auftrag von Peter Dalgaard
Gesendet: Donnerstag, 30. Juni 2005 11:48
An: Prof Brian Ripley
Cc: Dubravko Dolic; r-help at stat.math.ethz.ch
Betreff: Re: [R] Memory Management under Linux: Problems to allocate large amounts of data

Prof Brian Ripley <ripley at stats.ox.ac.uk> writes:

> On Thu, 30 Jun 2005, Dubravko Dolic wrote:
> 
> > Dear Prof. Ripley.
> >
> > Thank You for Your quick answer. Your right by assuming that we run
> > R on a 32bit System. My technician tried to install R on a emulated
> > 64bit Opteron machine which led into some trouble. Maybe because the
> > Opteron includes a 32bit Processor which emulates 64bit (AMD64
> > x86_64). As You seem to have good experience with running R on a
> > 64bit OS I feel encouraged to have another try for this.

Er? What is an "emulated Opteron" machine? Opterons are 64 bit.
 
> It should work out of the box on an Opteron Linux systen: it does for
> example on FC3 and SuSE 9.x.  Some earlier Linux distros for x86_64 are
> not fully 64-bit, but we ran R on FC2 (although some packages could
> not be installed).
> 
> Trying to build a 32-bit version of R on FC3 does not work for me: the
> wrong libgcc_s is found.  (One might want a 32-bit version for speed
> on small tasks.)

On FC4 it is even easier: "yum install R R-devel" gets you a working R
2.1.1 straight away (from Fedora Extras). Only if you want to include
hardcore optimized BLAS or do not like the performance hit of having R
as a shared library do you need to compile at all.

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