What is the difference between an AIX 64-bit kernel and an AIX 32-bit kernel

Question: How are you sure the machine will run a 64-bit kernel?

Answer: Running the 64-bit kernel requires 64-bit hardware. For AIX 5.2, all IBM eserver pseries 64-bit hardware can run 64-bit or 32-bit cores. The order is as follows:

#/usr/sbin/bootinfo-p

When running on a machine that can only run a 32-bit kernel, the string "32" is returned. If the machine can run a 64-bit kernel or a 32-bit kernel, the command returns "CHRP".

In AIX 5.2, the 32-bit kernel is installed by default. The 64-bit kernel and the JFS2 (Enhanced logging file system) can be enabled at installation time.

Question: Can I use an application built on a 32-bit or 64-bit kernel?

Answer: perfectly OK. The environment in which an application is built is not related to where it can run. You can use a compiler switch to create 32-bit or 64-bit executables from the program source code when compiling on a 32-bit or 64-bit kernel. In addition, 32-bit programs and 64-bit programs can run on 32-bit or 64-bit cores.

Question: Can a 32-bit application run on a 64-bit kernel?

Answer: almost certainly can. The only scenario where a 32-bit application cannot run on a 64-bit kernel is when an application needs to use kernel extensions that are available only in 32-bit mode (extensions to the kernel and possible programs, such as programs that provide new system calls to the application). An example of this scenario is Oracle 8i, which contains a kernel extension that enables only 32-bit. Oracle 9 does not have this type of restriction to run on a 64-bit kernel. Applications generally do not provide extensions.

Question: Does all input work on a 32-bit kernel or 64-bit kernel?

Answer: Input without a 64-bit kernel extension will not be configured by the 64-bit kernel. Almost all I/O devices capable of working on a 32-bit kernel can also work on 64-bit cores.

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Question: Can I run JFS2 (enhanced log file system) on a 32-bit kernel?

Answer: Although not recommended, the JFS2 on the 32-bit kernel is supported on AIX 5.2. Although JFS2 provides significant scalability improvements on a JFS basis, its full potential can only be achieved through a 64-bit kernel. The 64-bit kernel provides a better environment for running JFS2, because the 32-bit kernel's scaling potential is far more restrictive than it is. The combination of the 64-bit kernel and the JFS2 is designed to achieve much superior performance in file system performance than any other file system and kernel combination. Recommended

Use the JFS with the 32-bit kernel.

Problem: To install AIX 5.1 with a new and complete rewrite and want to select the 64-bit kernel. What should I do?

Answer: If your system has a 64-bit processor, the 64-bit kernel will be installed automatically with the base operating system. However, the 64-bit initial kernel is enabled only when you enable the 64-bit kernel and the JFS2 option to Yes in the initial AIX installation process.

To do this, go to the advanced option in the AIX installation process and select Yes for the 64-bit kernel. When you do this, you will use JFS2 (also known as an enhanced log file system).

Question: Can I change back to 32 digits after 64-bit installation?

Answer: Yes, you can change back to 32 bits by booting to the service and pointing back to the UNIX symbol link to the UNIX_MP (32-bit kernel). Perform bosboot and reboot the partition.

>32---

# Ln-sf/usr/lib/boot/unix_32/unix

# Ln-sf/usr/lib/boot/unix64/usr/lib/boot/unix

# Bosboot-ad/dev/ipldevice

# Shutdown-r

--->64

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

# Ln-sf/usr/lib/boot/unix64/usr/lib/boot/unix

# Bosboot-ad/dev/ipldevice

# Shutdown-r