On Jan 12, 1:52 pm, Sion Arrowsmith <si... at chiark.greenend.org.uk> wrote: > And today's moral is: try it before posting. Yeah, I can map a 2GB > file no problem, complete with associated 2GB+ allocated VM. The > addressing is clearly not working how I was expecting it too. The virtual memory space of a 32 bit process is 4 GB.