In the next two articles, I'd like to take a look at processes.
This week, we'll see what a process is and how to view
information regarding your processes. Next week, we'll look at
doing useful things with this process information. Like any
other Unix system, FreeBSD is a multitasking, multiuser
operating system. This means that a number of users can each be
running a number of programs at the same time. It is the
kernel's responsibility to ensure that each of these programs
gets a fair turn at your computer's CPU and that each user
receives the correct results from their program's execution.
When you start a program, it is loaded into RAM and is called a
process, as its instructions need to be processed by the CPU. In
order for the kernel to keep track of which programs are running
and which user started which program, each process is assigned a
process ID, or PID. Usually, the PID will be associated with,
and have the same permissions as, the user who started the
program and that user's primary group. Not