https://community.intel.com/t5/Software-Archive/Memory-Allocation-Problems/m-p/979563#M25751 If you're talking x86 Linux, yes. Alpha Linux and Itanium Linux are 64-bit.<BR /><BR />Steve Tue, 15 Jan 2002 05:13:06 GMT Steven_L_Intel1 2002-01-15T05:13:06Z https://community.intel.com/t5/Software-Archive/Memory-Allocation-Problems/m-p/979558#M25746 I have a dual Athlon machine with 2 GB of physical RAM and 3 GB of virtual memory. When I try to allocate 2 double precision arrays of size greater than 11250 by 11250, the application exits with an insufficient virtual memory error. This is very strange!!! At 11250,11250 size, 8 bytes per array gives me a total memory requirement of only 1.93 GB. So what is going on? I have searched the Compaq knowledge base without success. Any help is much appreciated. <BR /> <BR />p.s. increasing the VM allocation to 4 GB did not help either. Thu, 10 Jan 2002 15:34:08 GMT https://community.intel.com/t5/Software-Archive/Memory-Allocation-Problems/m-p/979558#M25746 sprasad 2002-01-10T15:34:08Z https://community.intel.com/t5/Software-Archive/Memory-Allocation-Problems/m-p/979559#M25747 You hit the OS limit. 32 bits can address 4GB of memory, of which Windows reserves 2 GB for itself. What's left is in theory 2GB but in practice you can hardly get more than about 1.7. <BR /> <BR />Jugoslav Thu, 10 Jan 2002 20:52:34 GMT https://community.intel.com/t5/Software-Archive/Memory-Allocation-Problems/m-p/979559#M25747 Jugoslav_Dujic 2002-01-10T20:52:34Z https://community.intel.com/t5/Software-Archive/Memory-Allocation-Problems/m-p/979560#M25748 Windows reserves 2 GB for itself???? I didn't know that - I knew about the 4 GB addressable limit, but didn't realise that applications were limited to a max of 2 GB. I may have to seriously consider moving to Linux now. Fri, 11 Jan 2002 06:50:14 GMT https://community.intel.com/t5/Software-Archive/Memory-Allocation-Problems/m-p/979560#M25748 sprasad 2002-01-11T06:50:14Z https://community.intel.com/t5/Software-Archive/Memory-Allocation-Problems/m-p/979561#M25749 Jogoslav is correct. More specifically, process address space is 2GB, and system (shared) address space is 2GB. This is a popular design in 32-bit operating systems. <BR /><BR />If you want more, you'll need a 64-bit processor such as Alpha and a 64-bit OS (Linux will do). WIndows NT on Alpha was 32-bits. Linux and Windows on Itanium are 64-bit, but this may or may not be an appropriate solution for you now.<BR /><BR />Steve Fri, 11 Jan 2002 09:23:14 GMT https://community.intel.com/t5/Software-Archive/Memory-Allocation-Problems/m-p/979561#M25749 Steven_L_Intel1 2002-01-11T09:23:14Z https://community.intel.com/t5/Software-Archive/Memory-Allocation-Problems/m-p/979562#M25750 From Steves answer one can conclude that working with 32 bits we will found the same limit in memory addresable under windows and under linux? Tue, 15 Jan 2002 04:15:34 GMT https://community.intel.com/t5/Software-Archive/Memory-Allocation-Problems/m-p/979562#M25750 jhp 2002-01-15T04:15:34Z https://community.intel.com/t5/Software-Archive/Memory-Allocation-Problems/m-p/979563#M25751 If you're talking x86 Linux, yes. Alpha Linux and Itanium Linux are 64-bit.<BR /><BR />Steve Tue, 15 Jan 2002 05:13:06 GMT https://community.intel.com/t5/Software-Archive/Memory-Allocation-Problems/m-p/979563#M25751 Steven_L_Intel1 2002-01-15T05:13:06Z