There was a time when the process was the smallest schedulable entity of concern to the kernel; today, however, that honor belongs to the thread. Before we discuss HP-UX kernel structures in depth, we must define the relationship between programs, processes, and threads.
The term program refers to a file that stores an executable image. A program file contains a header record defining the architecture for which it was compiled, magic numbers, and a list of system resources it will require access to during its execution life cycle.
The first HP series 800 computers were based on the then newly developed 32-bit HP Precision Architecture (PA-RISC 1.x) chip set. This product line was called the Spectrum computing platform. ...