How to know x86 system capable running 64-bit software

How can you tell whether your operating system supports 64-bit, 32-bit, or 16-bit applications? This article explains. The microprocessor architecture has two operating modes: Long mode and Legacy mode. Long mode (lm): runs under a 64-bit operating system and supports native 64-bit mode and 32-bit/16-bit compatibility mode. This means it supports 64-bit, 32-bit, and 16-bit applications. Legacy mode: runs under 16-bit and 32-bit operating systems, so it cannot support 64-bit applications. The following command checks whether the system can run 64-bit programs. #grep lm /proc/cpuinfo If the output resembles the following example or contains the lm flag, the system can run 64-bit programs. flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx mmxext lm 3dnowext 3dnow