HP 3000 Manuals

System Startup, Configuration, and Shutdown Reference Manual

Chapter 2  Initiating System Activity 

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.

MPE/iX 5.0 Documentation