Hi, here I've a dedicated server with 12GB RAM and running Debian Lenny x64. dmesg | grep Memory [ 0.004000] Memory: 11917152k/12259740k available (2279k kernel code, 333820k reserved, 1022k data, 216k init) Since some days, I've another dedicated server (nearly same hardware), but with Debian Squeeze x64 (installed via debootstrap, Kernel 2.6.32-5-xen-amd64) dmesg | grep Memory [ 1.551510] Memory: 6864620k/8151916k available (3146k kernel code, 1057736k absent, 229560k reserved, 1901k data, 600k init) what does absent memory mean? And how can I get 1GB of RAM back?