> > Limit 32-bit compatible process in 0-2GB virtual address range > > (which is enough for real scenarios), because it could avoid > > address sign extend problem when 32-bit enter 64-bit and ease > > software design. Eh? I thought nearly all the other 32bit unix ports (of any flavour) put the user-kernel boundary at 3GB. (Apart from some very old sparc ones that use 3.5GB.) 2GB is used by Windows. I think the x86-64 32bit compat code even puts the boundary at 4GB. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)