Monday, August 5, 2013

Process management


Hello friends, in this blog I am going to write some information regrading process management in Unix like operating system(Ubuntu). Unix like operating system uses different file system compares to windows operating system. There are various process are running currently in operating system as shown in figure 1. this can be seen by using shell command “top”. Following figure 1 shows result of top command.
fig1. result of top command

Process:

Firstly we have to understand what is process, “process is a programm is currently in running”. At the time of process running process may go from various states are as: new born, runnable, running ,waiting, halt etc.

In Unix like operating system process are created by using system call like sys_fork() . Whenever a process is created in Ubuntu(Unix like) operating system firstly create process directory by there process id (pid) or by process name in file system. We can also check which are the process are currently running in the directory: /proc$

Now we are going to check that all running process are really going to create directory in “/procc$”. Look at figure 2 result of top command shows process running currently and also look at figure 3 shows contents of /proc$ directory.we can check the process in this directory by using command “ls”. Result of ls command is shown in figure 3.

fig2.result of top command



In this figure 2 look at the highlighted text shows process that is pid of process is 1575 created by user ravikumar, now look at figure 3 shows directory created by process id 1575 is highlighted.

fig3. contents of /proc$


Now the question arises that what is contained in this directory “1575” ? this directory contains details of process such as memory used by process, list of opened files by processes, cpu status, environmental variables, scheduling information, io devices used by process etc.

One more point i have to discuss regurding processes is “how much of the process can be created in unix like operating system can you guess”. OK don’t worry I will tell that maximum process process that are allowed to create are 32767. this is not complete discussion about process management.