PALO is a set of two programs, a boot loader, which is loaded by the PA-RISC firmware into memory and then executed, and a boot media management tool, which prepares and updates bootable media such as hard disk drives.
The PALO boot loader executable is stored in a file called
iplboot. 'IPL' is HP
jargon for Initial Program Loader
(See the glossary).
The boot media management tool is called PALO, which
stands for PA/Linux LOader, just as on x86 the boot media
management tool is called LILO.
Even though PALO is much alike LILO (both have a userland application and a boot loader executable), it's worth mentioning that PALO doesn't usually need to be called every time you build and install a new kernel, as LILO does[2].
PALO is strongly related to PA/Linux development. Thus, several versions have been released. Some changes in the way make palo operates are explained by the author of PALO, Paul Bame, in this mail.