Essay Example about Process Management in UNIX Operating System

UNIX is a multi-user and multi-processing operating system. A process in UNIX system is generally referred to as an instance of a program which begins after fork system call has created it and ends when exit system terminates it. Normally, UNIX processes are categorized into two types: foreground and background processes. Foreground processes run on the screen and require a user input while background processes do not require user input and they run in the background. This paper discusses how UNIX operating system manages its processes.

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UNIX uses various commands such as fg, df, free, PS, top, kill, and nice commands to effectively manage processes (van Vugt, 2015). The fg command is used to continue running a program that was initially stopped. In addition, the command brings the program to the foreground. On the other hand, a top command informs the user of the processes that currently run on a UNIX operating system while a PS command is an acronym for 'Process Status' and it is used to check all the running processes in a UNIX system.

It is essential to note that processes in UNIX operating system are executed within a short computational time called time slice or quantum. This slice time is usually between 0.1 and 1 second. This means that In a UNIX, the time slice is usually between 0.1 and 1 second. This implies that a single process is run for a time slice, after which the CPU or processor is withdrawn from it and subsequently allocated another process. This new process also executes for a time slice, thereafter the CPU is withdrawn and given the processes that follow. It is worthy to understand that UNIX kernel's process management part allocates CPU to various processes. The management part schedules as well as switch context for a subsequent process that is just about to run (Liu, Yue, & Guo, 2011).

To terminate a running process, kill command is used. It is important to note that kill command requires the use of a process ID to effectively terminate a running process. As earlier mentioned, UNIX is a multi-process operating process in which a lot of processes may run concurrently, thereby lowering the speed of high priority processes. The ramification for this is poor performance. Nice command helps in prioritizing processes so that the most urgent processes run first before the other processes that are non-urgent. Nice command is assigned values between -20 and 19. A lower value of nice index is an indication of a high priority given to that particular task. However, in order to change the priority given a process, a re-nice command is used. Lastly, free command shows the used and free RAM of UNIX system while a df command reports free hard disk on all the available file systems of UNIX operating system. Imperatively, information about the RAM and hard disk is useful in improving the efficiency of UNIX processes (van Vugt, 2015).

In conclusion, managing processes in a UNIX operating system involves the use of various commands. These commands help in creating processes, executing the processes created, and terminating the processes when their lifetime expires. Notably, there are multiple processes that compete for the CPU of a UNIX system. To ensure that all processes are taken care of, each process is allocated a specific time, usually 0.1 to 1 sec, to run on a CPU. Processes that are urgent are given the highest priority. The command that helps in achieving this is the nice command.

References

Liu, Y., Yue, Y., & Guo, L. (2011). UNIX Process Management. In UNIX Operating System (pp. 81-122). Springer, Berlin, Heidelberg.

van Vugt, S. (2015). Process and System Management. In Beginning the Linux Command Line (pp. 211-229). Apress, Berkeley, CA.