如何在安装完的系统上面使用64位核心

If you want to enable the 64-bit kernel after system installation, you will need to
instruct the system to use the 64-bit kernel information stored in the /usr/lib/boot
directory. There are three kernels available in the /usr/lib/boot directory:
unix_up 32-bit kernel for uniprocessor systems
unix_mp 32-bit kernel for multiprocessor systems
unix_64 64-bit kernel for 64-bit processor systems
The following example provides the commands to run to enable the 64-bit kernel
after system installation:
# ln -sf /usr/lib/boot/unix_64 /unix
# ln -sf /usr/lib/boot/unix64 /usr/lib/boot/unix
# bosboot -ad /dev/ipldevice
# shutdown -r
After the system has rebooted, it will be running the 64-bit kernel. To reactivate
the 32-bit kernel, follow the same procedure, substituting unix_up or unix_mp for
unix_64, depending on your system type.

原文转自：http://www.ltesting.net