changing 32bit kernel to 64bit kernel

how would you change a 32bit kernel to 64bit. In aix5L the procedures are:

1. smitty load64bit

This will take you to the following menu :

Enable Now
Enable/Disable at System Restart

2. Select enable now and then select enable 64 bit env. at system restart.
3. A line is added to inittab to load this automatically at system reboot.

If you are not sure, try this command:

To switch from 32-bit mode to 64-bit mode run the following commands, in the given order:

1. ln -sf /usr/lib/boot/unix_64 /unix
2. ln -sf /usr/lib/boot/unix_64 /usr/lib/boot/unix
3. bosboot -ad /dev/ipldevice
4. shutdown -Fr
5. bootinfo -K (should now show 64)

To switch from 64-bit mode to 32-bit mode run the following commands, in the given order:

1. ln -sf /usr/lib/boot/unix_mp /unix
2. ln -sf /usr/lib/boot/unix_mp /usr/lib/boot/unix
3. bosboot -ad /dev/ipldevice
4. shutdown -Fr
5. bootinfo -K (should now show 32)

Now, the biggest question would be, whu 64bit?

The advantages of a 64 bit kernel in memory addressing, maximum file size, maximum partition size, in the LVM if you use it and of course it faster.

FYI .In AIX4.3 the kernel is only 32-bit.