On Tue, 30 Oct 2007, Thomas Lumley wrote: > On Tue, 30 Oct 2007, David Bickel wrote: > >> To help me make choices regarding a platform for running high-memory R >> processes in parallel, I would appreciate any responses to these >> questions: >> >> 1. Does the amount of RAM available to an R session depend on the >> processor (Intel vs. Sun) or on the OS (various Linux distributions vs. >> Solaris)? > > Yes. > > It depends on whether R uses 64-bit or 32-bit pointers. For 64-bit R you > need a 64-bit processor, an operating system that will run 64-bit > programs, and a compiler that will produce them. > > I'm not sure what the current Intel offerings are, but you can compile > and run 64-bit on AMD Opteron (Linux) and Sun (Solaris) systems.
That is both Sparc Solaris and x86_64 Solaris (although for the latter you seem to need to use the SunStudio compilers). As far as I know all current desktop Intel processors run x86_64, and Xeons seem to have a price-performance edge at the moment. We have several boxes with dual quad-core Xeons and lots of RAM. (Not all for use with R, some Linux, some Windows.) Core 2 Duos do, and are commonplace in quite low-end systems. >> 2. Does R have any built-in limitations of RAM available to a session? >> For example, could it make use of 16 GB in one session given the right >> processor/OS platform? > > R does have built-in limitations even in a 64-bit system, but they are > large. It is certainly possible to use more than 16Gb of memory. > > The main limit is that the length of a vector is stored in a C int, and > so is no more than 2^31-1, or about two billion. A numeric vector of > that length would take up 16Gb on its own. ?"Memory-limits" documents them. >> 3. Is there anything else I should consider before choosing a processor >> and OS? > > I don't think there is anything else R-specific. -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
