7.3 TYPES OF PROCESSES:
 
PROCESSES within UNIX are classified into:

• INTERACTIVE PROCESSES            -->foreground process

• NON-INTERACTIVE PROCESSES   -->background process

• DAEMONS

7.3.1 INTERACTIVE PROCESSES (foreground process):
  
        The process created by the user with the SHELL  act upon the DIRECTIONS of the USER and are attached to the terminal ==> INTERACTIVE PROCESS.

7.3.2 NON-INTERACTIVE PROCESSES(background process):

        This type of processes is independent of terminal, and it can run without any attachment to the terminal ==> NON -INTERACTIVE PROCESSES.

7.3.3 DAEMONS:

        This processes run without holding any terminal and waiting for INSTRUCTIONS either from SYSTEM or the USER and immediately get  into action ==>DAEMONS.

ALIVE--------> till the SYSTEM is SHUTDOWN.

one cannot kill the processes prematurely.

7.4 RUNNING A COMMAND IN BACKGROUND:

    A command is made to run in the background by terminating the command line with an AMPERSAND(&) character.

eg:
$sort -o student.lst|student.lst &

The user may get into some problems under certain situations..they are:

• The IDENTIFICATION NUMBER is used to FIND SUCCESS OR FAILURE of the background process if it is NOT REPORTED.

• The OUTPUT has to be REDIRECTED to file otherwise the display on the monitor get MIXEDUP.

• Too many processes running ===>DEGRADES THE OVERALL EFFICIENCY OF THE SYSTEM.

• There is a danger of the user LOGGING OUT when some process running in the background.