LINUX Process Abstraction Flashcards
what is a process
is an operating-system level entity
as a program running in the operating system.
Every process in the LINUX operating system has a unique process ID or PID
which is an integer.
process vs program
When we issue a command to run a
program, a process is created in the operating system which runs the program.
a process as an instance of a running program.
The operating system could have many processes that are all running the same program.
processes in the operating system exist in a hierarchy
process has a unique parent (the process
that created it)
If a process creates new processes, they are called children of that process.
Children of the same process are called siblings
process is at the root of this
hierarchy is operating system kernel.
Process State
Running/Runnable: The process is running or is ready to run and is waiting for its turn to use the CPU.
Wait: The process is waiting for an event to occur, such as receipt of input from the keyboard or waiting for a child process to terminate.
Suspended: A process whose execution has been paused
Terminated: A state that briefly exists after a process has ended its execution while the operating system is releasing its resources and removing the process from the system.
Zombie: A process that has terminated and is waiting for its termination to be acknowledged by its parent.
signals
The operating system defines a set of signals.
Every process is capable of receiving these signals.\
