On Mon, 19 Jul 2004, Jeremy Mann wrote: > Farul M. Ghazali said: > > > If your user-space app is compiled as a 64-bit binary, it will see >4GB of > > RAM (or whatever your RAM + swap is). If your app is a 32-bit binary, it > > will see al the 4GB of RAM it can actually address, but nothing more. > > However, the 32-bit binaries don't have to share the 4GB address space wih > > other processes unlike what you're seeing with a 32-bit kernel/machine > > now. Note that this is assuming you're running a 64-bit kernel of course. > > Cmpiling 64-bit apps was a bit confusing at first (mixing 32-bit and > > 64-bit libs during linking, etc.) but we got the hang of it after a while. > > What OS are you using? I have SuSE 9.1 64bit on a dual Opteron with 4 gigs > of RAM. BIOS *sees* all 4 gigs, but SuSE with the 2.6.4 64bit kernel only > sees 3.19 gigs. I'm using gentoo, no problems there from the start. Haven't downloaded Suse yet, next on my list is Rocks for the small cluster we have. Have you tried rebuilding the kernel manually, a random guess is maybe the highmem support isn't enabled?