On Thu, Dec 05, 2002 at 12:31:00PM +0000, Brian J. Beesley wrote: > the entire _virtual_ address space is limited to 4 GBytes by the 32 bit > address bus, and the OS kernel claims some (usually half) of this, so that > the total memory usable by a single process is limited to 2 GBytes. (There > is a "big memory" variant of the linux kernel which expands this to 3 > GBytes, but the point still stands).
Actually, in newer Linux kernels (ie. at least all 2.4.x versions that I can remember) you can expand this further, up to 64GB on CPUs that support it (which is, AFAIK, Pentium Pro and newer, so in reality it won't be a problem). I don't really know what it does, but judging from the help entry, it appears like it can still only address 4GB at a time, so it's more or less `changing views' of what it can address all the time. This sounds like it might hurt performance when you want a lot of random memory access, though... /* Steinar */ -- Homepage: http://www.sesse.net/ _________________________________________________________________________ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
