Process managment

1. SUBMITTED BY:-NAVIYA MARIYA
MCA 3rd year

2.  A process is a program in execution .
 Eg:- In C or C++ the compiler creates the
binary code when we actually run the
binary it becomes a process.

3.  If a command issued , then it creates or
starts a new process.
 Eg:- pwd ,issued it used to list the current
directory location the user starts the
proess

4.  5 Digit id ,It keeps account of process.
 This id called process id or pid.
 Each process have unique pid.
 Used up process id again used.
 For newer process
 If all possible combinations are used.

5.  No two process have same process id.
 System keeps track of each process

6.  A process can be in two ways
 foreground process
 Background process

7.  Every process when started runs in
foreground by default, receives input from
the keyboard and sends output to the
screen.
When issuing pwd command
 $ ls pwd
Output:
 $ /home/prgmname/root

8.  It takes lots of time.
 No other process can start.

9.  It runs in the background without keyboard
input .
 Waits till keyboard input is required.
 Other processes can be done in parallel
with the process running in background .
 No need to wait for the previous process to
be completed.

10.  ps (Process status) can be used to see/list
all the running processes.
 Eg:- $ ps
PID TTY TIME
CMD
19 pts/1 00:00:00 sh
24 pts/1 00:00:00 ps
 -f for full information about the process

11. UID: User ID
PID: Process ID
PPID: Parent process ID
C: CPU utilization of process
STIME: Process start time
TTY: Terminal type associated with the
process
TIME: CPU time taken by the process
CMD: The command that started this
process

12.  When running in foreground, hitting Ctrl + c
(interrupt character) will exit the command.
 For processes running in background kill
command can be used if it’s pid is known.
 Eg:- $ kill 19 ;19 PID
Terminated
 If a process ignores a regular kill
command, you can use kill -9 followed by
the process ID .