Briefly explain the process management in UNIX.

UNIX makes use of the easy but powerful process facility that is visible to the user. UNIX follows the model in which the majority of the operating system executes within the environment of a user process. The model is like as follow:

In this the two modes the kernel and the user are required. UNIX utilizes two categories of processes 1) system processes and 2) user processes.

1) System processes run in kernel mode and implement operating system code to perform administrative and housekeeping functions, for example allocations of memory and process swapping.

2) User processes operate in user mode to implement user programs and utilities and kernel mode to implement instructions belongs to the kernel. A user process goes in kernel mode by issuing a system call, when exclusion (fault) is generated or when an interrupt take place.