3. INTRODUCTION
An operating system (OS) is system software that manages
computer hardware, software resources, and provides
common services for computer programs.
Operating system is a program which monitors, controls and
maintains the computer.
Operating System is a type of system software that is a
collection of programs which control the overall functions of
computer
Operating System is an interface between the users and the
hardware
When the computer is booted on, Operating System is first
loaded into the main memory
4. OBJECTIVE OF OPERATING SYSTEM
Make a computer system easier to use:- An operating system
hides details of hardware resources from programmers and other
users and provides them with a convenient interface for using a
computer system.
Manage the resources of a computer system:- An operating
system manages all the resources of a computer system. Efficient
and fair sharing of system resources among users and/or
programs is a key goal of all operating systems.
5. HISTORY OF OPERATING SYSTEM
Operating systems were first developed in the late 1950s to manage tape storage
The General Motors Research Lab implemented the first OS in the early 1950s for
their IBM 701
In the mid-1960s, operating systems started to use disks
In the late 1960s, the first version of the Unix OS was developed
The first OS built by Microsoft was DOS. It was built in 1981 by purchasing the 86-
DOS software from a Seattle company
The present-day popular OS Windows first came to existence in 1985 when a GUI
was created and paired with MS-DOS.
6. TYPES OF OPERATING SYSTEM
OS are classified into different types depending on their capability of processing
Single user Single task OS
Single user Multiple Task OS
Multi user OS
Multitasking OS
Multiprocessing OS
Real time OS
Embedded OS
7. TYPES OF OPERATING SYSTEM
Single-user, single task - As the name implies, this operating system is designed to manage the computer so
that one user can effectively do one thing at a time. Featured mobile phones (keypad mobile phone)
Single-user, multi-tasking - This is the type of operating system most people use on their desktop and
laptop computers today.
Multi user - multi user operating system uses to use a system by multiple users. In other word multi
user operating system allows a number of users to work simultaneously on a single computer system.
These types of operating systems are specially designed for the multi user system.
Examples of multi user operating systems includes Unix, Linux, Windows 2000 and VM - 386.
8. TYPES OF OPERATING SYSTEM
Multiprocessor operating system
The multiprocessor operating system allows the computer system to use more than one CPU in a single system
for executing more than one or multiple processes at a time. A computer system having multiple CPU process
faster than a system which contains a single CPU.
Examples of multiprocessor operating systems are Linux, Unix, windows 2000 etc.
Multitasking operating system
The multitasking operating system allow a user to give multitask at a same time on a single computer system
multitasking operating system are also known as multiprocessing operating system and multiprogramming
operating system. The number of tasks processed simultaneously by this operating system is depending upon
speed of CPU, the capacity of memory and size of programs.
Examples of multitasking operating systems are Linux, Unix, windows 2000, windows XP, windows 10.
9. TYPES OF OPERATING SYSTEM
Real time operating system
The real time operating system is similar as multitasking operating system. However, these operating systems are
specially designed to handle real time applications. Real time applications are those applications which have to
execute within a specific period of time. Therefore, time is major constraint for these applications.
The different examples of real time applications are robots, machine learning, control machinery, scientific
instruments and industrial systems. etc.
Embedded operating system
The embedded operating system is similar to real time operating system. This operating system is installed on an
embedded computer system which is primary used to perform computational tasks in electronic devices.
Examples of embedded operating systems are palm operating system, windows CE.
10. FUNCTIONS OF OPERATING SYSTEM
Booting the computer
Performs basic computer tasks eg managing the various peripheral devices eg. mouse, keyboard
Provides a user interface, e.g. command line, graphical user interface (GUI)
Handles system resources such as computer's memory and sharing of the central processing unit
(CPU) time by various applications or peripheral devices
Provides file management which refers to the way that the operating system manipulates, stores,
retrieves and saves data.
11. FUNCTIONS OF OPERATING SYSTEM
Memory Management
Device Management
Processor Management
File Management
Communication Management
Security
Error Detection
Coordination among Software and Users
Job accounting
User Interface
12. MEMORY MANAGEMENT
Keeps track of the primary memory, i.e. what part of it is in use by
whom, what part is not in use, etc. and allocates the memory when a
process or program requests it. Memory management also performs
these tasks
Upgrading the performance of the computer system
Enabling the execution of multiple process at the same time
Sharing the same memory space among different process
13. DEVICE MANAGEMENT
An OS with help of their respective drivers manages device
communication. Following activities are performed by an Operating
System for device management:
It Keep a track of all devices. This task is performed by I/O
controller.
It decides which process will get the device when and for how long.
It allocates and de-allocates the device efficiently.
14. PROCESSOR MANAGEMENT
In a multi-programming environment, it is OS who decides which process
will get the processor when and for how long. This task is called Process
Scheduling. Following activities are done by Operating System for
processor management:
It keeps a track of processor tasking and checks the status of process.
Traffic controller performs this task.
It allocates the processor and also de-allocates processor when a process
is complete and not required.
It also handles these process, all the process from start to shut down.
Booting, open, save, install, copy, print, send, etc.
15. FILE MANAGEMENT
In a file system, generally directories are organized for usage and easy
navigation. Following activities are performed by an OS under file
management:
It keeps a track of location, information, status etc. This collective is
known as File System.
It decides who will get the resources.
It allocates and de-allocates the resources.
Features like Name, Folders, Location, Attributes (size, type, modified,
protection, password etc. are managed under file management.
16. COMMUNICATION MANAGEMENT
The communication management part of OS does the following task
that makes the system easy, efficient and suitable to use and operate
User – Application S/W – Hardware.
One computer to other computer in LAN/WAN.
Command interpretation.
Downloading-Uploading.
17. PROTECTION AND SECURITY
Prevents unauthorized access to programs and data by means of passwords
and other similar techniques.
Protection ensures that resources are used in consistent manner.
Security mechanism prevents unauthorized access to the computer like
security of s/w, security of data stored in the computer, and security of
physical resources.
In a networked environment the data or resources sharing should be done by
only trusted and authorized computer.
Virus management, alert messages, dialogue boxes, firewall, passwords/
access protection.
18. OTHER FUNCTIONS OF OPERATING SYSTEM
Error-detecting Aids − Production of dumps, traces, error
messages, and other debugging and error-detecting methods.
Coordination Between Other Software and Users −
Coordination and assignment of compilers, interpreters,
assemblers, and other software to the various users of the
computer systems.
Control Over System Performance − Records delays between the
request for a service and from the system.
19. OTHER FUNCTIONS OF OPERATING SYSTEM
Job Accounting − Keeps track of time and resources used by
various jobs and/or users.
Interaction with the Operators − Interaction may take place via
the console of the computer in the form of instructions. The
Operating System acknowledges the same, does the
corresponding action, and informs the operation by a display
screen.
20. USER INTERFACE
The primary goal of OS is to make computer convenient for use by
it’s user. Its should allow users to easily access and communicate
with the applications and hardware. The user can interact with
computer by using mainly two types of interfaces:
Command Line Interface
Graphical User Interface
21. COMMAND LINE INTERFACE
Command line interfaces are the oldest of the interfaces. It involves
the computer responding to commands typed by the operator.
Example of Command Line Interface based OS are
Linux
MS DOS
22. GRAPHICAL USER INTERFACE
It is sometimes also referred to as WIMP because they
use Windows, Icons, Menus and Pointers. Operators use a pointing device to
control a pointer on the screen which then interacts with other on-screen
elements.
Some of GUI based OS are:
PARC (First GUI OS developed by Xerox Corp in 1981)
Microsoft Windows
Android
Apple iOS
23. GUI OPERATING SYSTEM
GUI OS for Computer
iOS
Linux
OS X
QNX
Microsoft Windows
IBM z/OS
RedHat
GUI OS for
Google Android OS
Apple iOS
BlackBerry
Symbian OS
Windows 8
