Python Class 11: Chapter 1 : Operating System, Functions of OS and User Interface

Functions of Operating System: (A) Process Management
While a computer system is operational, different tasks
are running simultaneously. A program is intended to
carry out various tasks. A task in execution is known
as process. We can activate a system monitor program
that provides information about the processes being
executed on a computer. In some systems it can be
activated using Ctrl+Alt+Delete. It is the responsibility
of operating system to manage these processes and get
multiple tasks completed in minimum time. As CPU is
the main resource of computer system, its allocation
among processes is the most important service of the
operating system. Hence process management concerns
the management of multiple processes, allocation
of required resources, and exchange of information
among processes.
(B) Memory Management
Primary or main memory of a computer system is
usually limited. The main task of memory management
is to give (allocate) and take (free) memory from running
processes. Since there are multiple processes running
at a time, there arises a need to dynamically (on-the-go)
allocate and free memory to the processes. Operating
system should do it without affecting other processes
that are already residing in the memory and once the
process is finished, it is again the responsibility of the
operating system to take the memory space back for re-utilization. Hence, memory management concerns with
management of main memory so that maximum memory
is occupied or utilised by large number of processes
while keeping track of each and every location within
the memory as free or occupied.
(C) File Management
Data and programs are stored as files in the secondary
storage of a computer system. File management involves
the creation, updation, deletion and protection of these
files in the secondary memory. Protection is a crucial
function of an operating system, as multiple users can
access and use a computer system. There must be a
mechanism in place that will stop users from accessing
files that belong to some other user and have not been
shared with them. File management system manages
secondary memory, while memory management system
handles the main memory of a computer system.
(D) Device Management
A computer system has many I/O devices and hardware
connected to it. Operating system manages these
heterogeneous devices that are interdependent. The
operating system interacts with the device driver and the
related software for a particular device. The operating
system must also provide the options for configuring
a particular device, so that it may be used by an end
user or some other device. Just like files, devices also
need security measures and their access to different
devices must be restricted by the operating system to
the authorized users, software and other hardware only.