Central Processing System (CPU) is the part of computer which executes computer programs.
To make it simple,a Program in execution is known as Process.
The thing which we need to keep in mind always is that:
Only one process can be executed per CPU/Core at a time.
So if we have 10 CPUs: the maximum number of processes that can be executed simultaneously with all these 1o CPUs is 10.
The processes that are ready to get executed in CPU but kept in queue in Memory are known as Runnable/Ready/Waiting Processes.
They are kept in Run-Queue or Ready Queue in memory.
When the process is taken for execution in CPU its known as running.
As expained before there can be only 1 running process per CPU at a time.
[There are four stages in CPU operation normally :fetch, decode, execute, and writeback, but I am not going into the details now.The terms are related about taking and giving back process from and to Memory.]
Also, the types of processes in a system can be classified as below:
2.Runnable or Ready.
Some processes may get swapped out to hard disk(virtual memory) also.
Normally after termination the proceses details should be removed from memory as well as process table.
If that is not happenning ,the resultant process is known as zombie.