AIX Switching Kernel Bit Modes

Switching to the 32 bit Kernel

1. Linking the 32 bit kernel.

   # ln -sf /usr/lib/boot/unix_mp /unix

   # ln -sf /usr/lib/boot/unix_mp /usr/lib/boot/unix

2. You will need to note which hdisks that hd5 appears on.

   # lslv -m hd5

3. Change the base operating system boot devices repeat for each disk listed in previous step.

   # bosboot -ad <hdisk#>

4. Add the drives to the bootlist that where listed with the lslv command.

   # bootlist -m normal <hdisk#> ... <hdisk#n>

5. Restart the server to apply the changes.
6. Verify that the server is running the 32 bit kernel.

   # bootinfo -K

Switching to the 64 bit Kernel

1. Ensure that the hardware is 64 bit enabled.

   # bootinfo -y

2. If the previous command returns 64 bit then proceed.
3. Linking the 64 bit kernel.

   # ln -sf /usr/lib/boot/unix_64 /unix

   # ln -sf /usr/lib/boot/unix_64 /usr/lib/boot/unix

4. You will need to note which hdisks that hd5 appears on.

   # lslv -m hd5

5. Change the base operating system boot devices repeat for each disk listed in previous step.

   # bosboot -ad <hdisk#>

6. Add the drives to the bootlist that where listed with the lslv command.

   # bootlist -m normal <hdisk#> ... <hdisk#n>

7. Restart the server to apply the changes.
8. Verify that the server is running the 64 bit kernel.

   # bootinfo -K

Resources

1. IBM pSeries and AIX Information Center
2. AIX Commands you should not leave home without