Process is an executing program with several components and

proprieties.

1.exec thread

2. PID

3. priority

4. memory context

5. enviornment

6. file descriptors

7. security credentials.

processes began through a process called "fork and exec".

that is when one command starts another, the child process

first forks , the kernel copying over pages of memory from

the present process to a new location for the child process.

The child then execs, executing the new command and

overwriting the data.the thread is , which controls the flow

of the process. A process needs at least one thread.