Job Control allows user to start multiple processes from a terminal and have some control over their execution. It is introduced in 4.3BSD which is then widely adopted by other Unix-like operating system including #Linux. It requires support from the terminal driver, the signal mechanism and the shell, meaning if the shell supports the Job Control mechanism, but the underlying operating system doesn’t, then it is not possible to do Job Control on it.
Job Control is done through by assigning unique process group ID (pgrp) to the process instead of inheriting its parent process pgrp. When a SIGKIL sent to the parent process, it will not terminate of its children, instead, those child processes will live a longer life than their parent.