Operating System

Created By : Apoorv Khare

 Operating System : Introduction

An Operating system (OS) is a software which acts as an interface between the end user and
computer hardware.

Every computer must have at least one OS to run other programs.

An application like Chrome, MS Word, Games, etc needs some environment in which it will run and
perform its task.
Operating System : Intro

The OS helps you to communicate with the

computer without knowing how to speak the
computer's language.

It is not possible for the user to use any

computer or mobile device without having an
operating system.

Ex Windows, Android, iOS, Mac OS, Linux, Unix,

etc.
Operating System : Features

● Protected and supervisor mode

● Allows disk access and file systems Device
drivers Networking Security
● Program Execution
● Memory management Virtual Memory
Multitasking
● Handling I/O operations
● Manipulation of the file system
● Error Detection and handling
● Resource allocation
● Information and Resource Protection
 OS : Kernel

The kernel is the central component of a

computer operating systems.The only job
performed by the kernel is to the manage the
communication between the software and the
hardware.

It makes the communication between the

hardware and software possible.While the Kernel
is the innermost part of an operating system, a
shell is the outermost one.
Features of Kernel

● Low-level scheduling of processes

● Inter-process communication
● Process synchronization
● Context switching
Operating System :
Functions
Operating System : Functions

In an operating system software performs each of the function:

1. Process management:- Process management helps OS to create and delete processes. It also
provides mechanisms for synchronization and communication among processes.
2. Memory management:- Memory management module performs the task of allocation and
de-allocation of memory space to programs in need of this resources.
3. File management:- It manages all the file-related activities such as organization storage,
retrieval, naming, sharing, and protection of files.
4. Device Management: Device management keeps tracks of all devices. This module also
responsible for this task is known as the I/O controller. It also performs the task of allocation and
de-allocation of the devices.
Operating System : Functions

5. I/O System Management: One of the main objects of any OS is to hide the peculiarities of that
hardware devices from the user.
6. Secondary-Storage Management: Systems have several levels of storage which includes primary
storage, secondary storage, and cache storage. Instructions and data must be stored in primary
storage or cache so that a running program can reference it.
7. Security:- Security module protects the data and information of a computer system against
malware threat and authorized access.
8. Command interpretation: This module is interpreting commands given by the and acting system
resources to process that commands.
Operating System : Functions

9. Networking: A distributed system is a group of processors which do not share memory, hardware
devices, or a clock. The processors communicate with one another through the network.
10. Job accounting: Keeping track of time & resource used by various job and users.
11. Communication management: Coordination and assignment of compilers, interpreters, and
another software resource of the various users of the computer systems.
Operating System : Types

● Batch Operating System

Some computer processes are very lengthy and
time-consuming. To speed the same process, a
job with a similar type of needs are batched
together and run as a group.

The user of a batch operating system never

directly interacts with the computer. In this type of
OS, every user prepares his or her job on an
offline device like a punch card and submit it to
the computer operator.
Operating System : Types

● Multi-Tasking/Time-sharing Operating
systems
Time-sharing operating system enables people
located at a different terminal(shell) to use a
single computer system at the same time. The
processor time (CPU) which is shared among
multiple users is termed as time sharing.
Operating System : Types

● Multiprocessing OS :

Most computer systems are single processor

systems i.e they only have one processor.
However, multiprocessor or parallel systems are
increasing in importance nowadays. These
systems have multiple processors working in
parallel that share the computer clock, memory,
bus, peripheral devices etc.
Operating System : Types

● Real time OS
A real time operating system time interval to process and respond to inputs is very small. Examples:
Military Software Systems, Space Software Systems.

● Distributed Operating System

Distributed systems use many processors located in different machines to provide very fast
computation to its users.
Operating System : Types

● Mobile OS
Mobile operating systems are those OS which is especially that are designed to power smartphones,
tablets, and wearables devices.

Some most famous mobile operating systems are Android and iOS, but others include BlackBerry,
Web, and watchOS.
Final Points About OS

Advantages : Disadvantages :

● Allows you to hide details of hardware by ● If any issue occurs in OS, you may lose all
creating an abstraction the contents which have been stored in
● Easy to use with a GUI your system
● Offers an environment in which a user ● Operating system's software is quite
may execute programs/applications expensive for small size organization
● Operating System acts as an intermediary which adds burden on them. Example
among applications and the hardware Windows
components ● It is never entirely secure as a threat can
● It provides the computer system resources occur at any time.
with easy to use format.
● An operating system is a software which acts
as an interface between the end user &
computer hardware.
● OS were 1st developed in the late 1950s to
manage tape storage.
● The kernel is the central component of a
computer OS. The only job performed by the
kernel is to manage the communication b/w
the software and the hardware.
● The two most popular kernels are Monolithic
and MicroKernels.
● Process, device, file, i/o, secondary storage,
memory management are various functions of
an OS
● Batch, Multitasking/Time sharing,
Multiprocessing, Real Time, Distributed,
Mobile, Network are various types of
Operating Systems.