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 .