IBM RS/6000 44P - Manual (Page 95)

The following describes the choices available on this
screen.
Select Software: This option, if supported by the
operating system, allows you to choose which operating
system to use. Choosing an operating system causes the
system to start. This option is supported by AIX. However,
not all operating systems support this option.
If you receive an informational message saying that no
operating system is installed, then the system information
in nonvolatile storage may have been lost. This situation
can occur if the battery has been removed. To correct this
situation, refer to the bootlist reference in your AIX
operating system documentation.
Software Default: This option, if supported by the
operating system, enables you to select a default
operating system for your system unit.
Software
Default
Install
From
Select
Software
Boot
Device
OK prompt
Multiboot Startup
OK
EXIT
Chapter 4. System Management Services 77