changing the AIX kernel to 64 bit mode

Enter the following commands:

ln -sf /usr/lib/boot/unix_64 /unix
ln -sf /usr/lib/boot/unix_64 /usr/lib/boot/unix
lslv -m hd5
bosboot -ad /dev/ipldevice
shutdown -Fr


to refer more about the determining the AIX platform is 32 bit or 64 bit, click here