32 vs 64-bit kernel

I was looking for a way to know if the customer's server is 32-bit or 64-bit.

I found very interesting information at http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.resources/faq.htm

I solved my doubt by running /usr/sbin/prtconf -c

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Will my machine run the 64-bit kernel?

64-bit hardware is required to run the 64-bit kernel. For AIX 5.3, all IBM Power Systems 64-bit hardware can run either the 64-bit kernel or the 32-bit kernel. To verify the processor capability, run the following command:

# /usr/sbin/prtconf -c 

The command will return "32" or "64" depending on the capability of the system. If your system does not have the prtconf command, you can use the bootinfo -y command.

OnPOWER5™ and later systems,AIX 5.3 will install the 64-bit kernel by default.

Is there a way to check the current system kernel for 32-bit kernel vs. 64-bit kernel?

Yes. The command:

# /usr/sbin/bootinfo -K

returns "32" if the 32-bit kernel is enabled, and "64" if the 64-bit kernel is enabled.

Will my 64-bit application run on the 32-bit kernel?

Most likely. The environment in which the application was built has no bearing on where it can run. Compiler switches are available to create either a 32-bit or a 64-bit executable program from program source code when compiled on either the 32-bit kernel or the 64-bit kernel. In addition, 32-bit programs and 64-bit programs can both be run on either the 32-bit kernel or the 64-bit kernel. However, if your application needs the use of a kernel extension (a program that extends the kernel and may, for example, provide a new system call for the application) which is not supported on both the 32- and 64-bit kernels, your application will only run with the kernel supported by the kernel extension.

Will my 32-bit application run on the 64-bit kernel?

It almost certainly will. The only case where a 32-bit application will not run on the 64-bit kernel is when an application needs the use of a kernel extension (a program that extends the kernel and may, for example, provide a new system call for the application) that is only available in 32-bit mode. One example of this is Oracle 8i, which contains a kernel extension that is only 32-bit enabled. Oracle 9 has no such restriction and runs on the 64-bit kernel. Applications do not normally provide kernel extensions.

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