Separate firmware routines of processor-dependent code (PDC)
and input/output-dependent code (IODC) perform the system self-test
and initialization after resetting HP Precision Architecture hardware.
The initial program load (IPL), the first software retrieved
from the boot device, implements the operating-system-independent
portion of the bootstrap process. The initial system loader (ISL),
a boot-device- based IPL utility, provides the user interface for displaying
or modifying system startup functions.