How to determine if AIX uses a 32-bit kernel or 64-bit kernel ?

Problem:

This technote explains how to establish if an IBM® AIX® host is 32-bit or 64-bit capable in order to determine which version of IBM® Rational® ClearCase® to install.

Resolving the problem

The getconf command is available in AIX 5L and enhanced in Version 5.2. The command provides information about system configuration variables. The main information intended from the enhancement refers to memory, disk size, last boot device, and hardware check for 32-bit or 64-bit, and the same for the kernel. The getconf command is enhanced to provide extra information that is currently available with the unsupported bootinfo command. The getconf command uses the ODM library routines to extract information from the device configuration database. The getconf command issues a setuid root to access privileged configuration variables.

The syntax of the command is as follows:

getconf [ -v specification ] [ SystemwideConfiguration | PathConfiguration PathName ] [ DeviceVariable DeviceName]

Where the variable names are defined as provided in the following table:

Table 1. System wide configuration names

Variable	Description
System wide configuration names
BOOT_DEVICE	Displays last boot device
MACHINE_ARCHITECTURE	Displays machine architecture type (chrp)
MODEL_CODE	Displays model code
KERNEL_BITMODE	Bit mode of the kernel, 32-bit or 64-bit
REAL_MEMORY	Real memory size in KB
HARDWARE_BITMODE	Bit mode of the machine hardware, 32-bit or 64-bit
MP_CAPABLE	MP Capability of the machine
Path configuration names
DISK_PARTITION	Physical partition size of the disk
DISK_SIZE	Disk size in MB
Device variables names
DISK_DEVNAME	Device name or location of the device

An example of the getconf command is shown in the following:

# getconf KERNEL_BITMODE
64
# getconf HARDWARE_BITMODE
64
# getconf DISK_SIZE /dev/hdisk0
140013
The size is reported in MB, so the disk above is a 140 GB disk.