The Process StructureIn addition to the references to the substructures, the process entry shown in Figure 4.1 contains the following categories of information: • Process identification: the PID and the parent PID • Signal state: signals pending delivery and summary of signal actions• Tracing: process tracing information• Timers: real-time timer and CPU-utilization counters  The process substruc..

4.2 Process StateEvery process in the system is assigned a unique identifier termed the process identifier (PID). PIDs are the common mechanism used by applications and by the kernel to reference processes. PIDs are used by applications when the latter send a signal to a process and when receiving the exit status from a deceased process. Two PIDs are of special importance to each process: the PI..