The document discusses different types of operating systems. It describes desktop operating systems, server operating systems, embedded operating systems, mobile operating systems, batch operating systems, multi-processor operating systems, multiprogramming operating systems, distributed operating systems, time-sharing operating systems, network operating systems, and mobile operating systems. For each type, it provides a brief definition and highlights some of their key advantages and disadvantages.

1. Operating System
Gevita
Chinnaiah
19/6/2023

2. Chapter 1 : Operating System
 What is an Operating System
 Computer System Structure
 Four Components of a Computer
System
 Functions of Operating System
 Types of Operating Systems
 Operating System Services
 Operating System Properties
 Exercise

3. What is an Operating System?
 A program that acts as an intermediary
between a user of a computer and the
computer hardware
 It is a program that manages hardware
resources.
 It provides services to application
programs.
Operating system goals:
◦ Execute user programs and make solving
user problems easier
◦ Make the computer system convenient to use
◦ Use the computer hardware in an efficient
manner

4. Computer System Structure
Computer system can be divided into four
components
 Hardware – provides basic computing resources
◦ CPU, memory, I/O devices
 Operating system
◦ Controls and coordinates use of hardware among
various applications and users
 Application programs – define the ways in which
the system resources are used to solve the
computing problems of the users
◦ Word processors, compilers, web browsers, database
systems, video games
 Users
◦ People, machines, other computers

5. Four Components of a
Computer System

6. Functions of Operating
System
Memory Management
 Main memory provides a fast storage that
can be access directly by the CPU.
◦ Keeps tracks of primary memory i.e. what
part of it are in use by whom, what part are
not in use.
◦ In multiprogramming, OS decides which
process will get memory when and how
much.
◦ Allocates the memory when the process
requests it to do so.
◦ De-allocates the memory when the process
no longer needs it or has been terminated.

7. Functions of Operating
System (Cont.)
Processor Management
 In multiprogramming environment, OS
decides which process gets the
processor when and how much time.
◦ Keeps tracks of processor and status of
process. Program responsible for this task
is known as traffic controller.
◦ Allocates the processor (CPU) to a
process.
◦ De-allocates processor when processor is
no longer required.

8. Functions of Operating
System (Cont.)
Device Management
 OS manages device communication via
their respective drivers.
◦ Keeps tracks of all devices. Program
responsible for this task is known as the I/O
controller.
◦ Decides which process gets the device when
and for how much time.
◦ Allocates the device in the efficient way.
◦ De-allocates devices.

9. Functions of Operating
System (Cont.)
File Management
 A file system is normally organized into
directories for easy navigation and
usage. These directories may contain
files and other directions.
◦ Keeps track of information, location, uses,
status etc. The collective facilities are often
known as file system.
◦ Decides who gets the resources.
◦ Allocates the resources.
◦ De-allocates the resources.

10. Functions of Operating
System (Cont.)
Other Important Activities
 Security
◦ By means of password and similar other techniques, preventing
unauthorized access to programs and data.
 Control over system performance
◦ Recording delays between request for a service and response from
the system.
 Job accounting
◦ Keeping track of time and resources used by various jobs and users.
 Error detecting aids
◦ Production of dumps, traces, error messages and other debugging
and error detecting aids.
 Coordination between other software and users
◦ Coordination and assignment of compilers, interpreters, assemblers
and other software to the various users of the computer systems.

11. Types of Operating
Systems

12. Is There More Than One Type
of OS?
•Generally, there are four types,
based on the type of computer
they control and the sort of
applications they support.
1. Desktop Operating
Systems

13. Types of Operating
Systems
2. Server Operating Systems
are specifically tailored to run on
servers, which are powerful
computers that serve multiple clients.

14. Types of Operating Systems
3. Embedded Operating Systems
RTOS are used to control machinery,
scientific instruments, and industrial
systems.
There is typically very little user-
interface capability.

15. Types of Operating Systems
4. Mobile operating systems
are designed for smartphones, tablets,
and other mobile devices.
Popular mobile operating systems include
Android (developed by Google), iOS
(developed by Apple), and Windows 10
Mobile.

16. Batch Operating System
 Users of a batch operating system don't
have direct contact with the computer.
 Advantages:
◦ It can be used by more than one person at
the same time.
◦ Cut down on how long it takes for the system
to run all the programs.
 Disadvantages:
◦ If a job doesn't work, the other jobs will have
to wait for a time that isn't known.
◦ Batch systems aren't always cheap.
◦ Hard to fix bugs in.

17. Multi-processor Operating
System
 If you have more than one CPU, you may
want to consider an OS designed for
multiprocessors. Multi-processor systems
typically use this operating system.
 Advantages:
◦ It's what makes it possible for the computer to
process several tasks at once.
◦ Games, scientific calculations, and financial
simulations are just a few examples of tasks that
can benefit from access to the whole processing
power.
 Disadvantages:
◦ They cost more because they need more CPUs
and memory units.

18. Multiprogramming Operating
System
 A single processor computer can run more than one
programs at the same time.
 Advantages:
◦ Reduced reaction time is one of its benefits.
◦ The ability to perform multiple tasks within the same
program at once could be useful.
◦ Multiple people can utilize the multiprogramming system
simultaneously.
◦ Unlike longer-term projects, short-term tasks can be
completed quickly.
◦ This has the potential to speed up the completion of
temporary projects.
◦ Increased CPU utilization and zero downtime are the
results.
◦ Smart use of resources is evident.

19. Multiprogramming Operating
System (Cont.)
 Disadvantages:
◦ It's incredibly intricate and complex.
◦ Computer processor scheduling is
essential.
◦ Operating systems require
memory management since all tasks are
kept in system memory.
◦ Managing everything is the more difficult
task.
◦ Long wait times for permanent positions
are to be expected if there are several

20. Distributed Operating System
 A distributed OS can run on a group of
computers at the same time.
 Distributed systems are used to spread data
and applications
 Distributed systems are also used by
computer networks to coordinate the parts of
their hardware and software that are shared
 Multiple computers share a single data link in
this type of network
 Each system has its own computing power
and storage space, which are not linked to
each other.

21. Distributed Operating System
(Cont.)
 Advantages:
◦ It is safer because if one computer fails, it won't affect
the other computers or the whole system.
◦ All computers can work on their own.
◦ Since resources are shared, the overall cost is lower.
◦ As more resources are shared, the system runs more
quickly.
◦ The load on the host system is lower.
◦ It is easy to add computers to the system.
 Disadvantages:
◦ High Setup cost.
◦ The whole system will fail if the server fails.
◦ Such a system uses software with a lot of moving
parts.

22. Time sharing Operating
System
 A time-sharing operating system is a
programs that allows numerous
concurrent users with a shared user
interface.
 It enables concurrent access to the same
resources, such as files and applications,
by several users who are simultaneously
logged in.
 his operating system is most prevalent in
businesses, particularly those with many
concurrent users
 Time-sharing operating systems allow
users to complete their tasks
concurrently.

23. Time sharing Operating
System (Cont.)
 Advantages:
◦ It delivers a speedy response.
◦ Reduces idle CPU time.
◦ Each task is assigned a set duration of time.
◦ Less likelihood of duplicate software.
◦ Improves response time.
◦ Friendly and user-friendly.
 Disadvantages:
◦ It utilizes numerous resources.
◦ Requires hardware with high specifications.
◦ It has a dependability concern.
◦ A problem with the security and integrity of user data and
programs.
◦ Probability of data transmission issues.

24. Network Operating System
 A network operating system, sometimes known as
NOS, is software that links several computers and
devices to a network and enables those devices to
share the network's resources.
 Advantages:
◦ It is easy to add new technology and hardware upgrades to
the system.
◦ The server can be accessed from different places and
different kinds of computers.
◦ The server in the middle is very stable.
◦ The server is in charge of security.
 Disadvantages:
◦ Most things have to do with the central location.
◦ It costs a lot of money to buy and run servers.
◦ It needs to be looked after and updated regularly.

25. Mobile Operating System
 Mobile operating systems are a subset of
operating systems (OS) developed specifically to
run on mobile devices such as smart phones ,
tablets , and wearable technology include smart
watches and smart glasses.
 Advantages:
◦ The ability to do multiple tasks.
◦ Stability and assurance of protection
◦ Utilizing mobility software to provide a great
experience for users.
◦ Capability of living up to the standards set by users.
◦ Secure mobile data access.
◦ Improve departmental communications.
◦ Aid for the labor force

26. Mobile Operating System
(Cont.)
 Disadvantages:
◦ Apps keep running even when you're not
using them.
◦ Things are hard for developers.
◦ Smartphones with low specs run slowly.
◦ Defence From Viruses. ...
◦ There are a lot of ads in apps.
◦ It doesn't help older people.
◦ You need a Google account.
◦ Software that has bad content.

27. Multi-tasking Operating
System
 Operating systems that support multi-tasking are built
with the intention of allowing numerous applications to
execute at the same time.
 Operating systems that support multitasking make it
possible for numerous people to collaborate
simultaneously on the same document or programs
 Advantages:
◦ Better response.
◦ Each task gets an equal opportunity.
◦ CPU idle time decreases which boosts the performance.
 Disadvantages:
◦ Since a single processor will be running multiple tasks, the
CPU will be busy and may get hot.
◦ Memory Boundation : During multitasking, the main
memory (RAM) has to hold more than one process, so
there could be a memory limit.

28. Client/Server Operating
System
 Client/server network operating systems
refer to networks with two types of
nodes, namely servers and clients.
 Both the server and client computers in a
client/server system must have particular
software installed in order to
communicate safely across a network
connection.
 The servers are the computers that
deliver network services.
 Client/server networks are typically
employed in corporate and government
applications.

29. Client/Server Operating
System (Cont.)
 Advantages:
◦ Allows companies to boost computing resources without buying
new hardware.
◦ Client-server systems can swiftly adapt to changing business
needs.
◦ Dedicated server solutions are less stable and harder to
maintain.
◦ Cheaper operations.
◦ More stable and manageable than dedicated server systems
 Disadvantages:
◦ These operating systems require more sophisticated
management and networking technology, longer start up times,
and increased attack susceptibility.
◦ Less secure than systems with dedicated servers.
◦ More difficult to scale than standalone server systems.

30. Real time Operating System
 A real-time operating system is an OS
for real-time applications that need to
process data and events in a very
specific amount of time
 Hard real-time systems
◦ Hard real-time systems guarantee that
critical tasks complete on time
 Soft real-time systems
◦ Soft real time systems are less restrictive

31. Real time Operating System
(Cont.)
 Advantages:
◦ Utilization of technology and resources to
their fullest extent.
◦ This system is nearly error-free.
 Disadvantages:
◦ Real-time Operating System employs very
complicated algorithms.
◦ Limited duties.
◦ Use Significant System resources.

32. Operating System Services
 An Operating System provides
services to both the users and to the
programs.
◦ It provides programs, an environment to
execute.
◦ It provides users, services to execute the
programs in a convenient manner.

33. Operating System Services
(Cont.)
 Program execution
◦ Loads a program into memory.
◦ Executes the program.
◦ Handles program's execution.
◦ Provides a mechanism for process
synchronization.
◦ Provides a mechanism for process
communication.
◦ Provides a mechanism for deadlock
handling.

34. Operating System Services
(Cont.)
 I/O Operation
◦ I/O operation means read or write
operation with any file or any specific I/O
device.
◦ Program may require any I/O device while
running.
◦ Operating system provides the access to
the required I/O device when required.

35. Operating System Services
(Cont.)
 File system manipulation
◦ Program needs to read a file or write a file.
◦ The operating system gives the permission to the
program for operation on file.
◦ Permission varies from read-only, read-write,
denied and so on.
◦ Operating System provides an interface to the
user to create/delete files.
◦ Operating System provides an interface to the
user to create/delete directories.
◦ Operating System provides an interface to create
the backup of file system.

36. Operating System Services
(Cont.)
 Communication
◦ Two processes often require data to be
transferred between them.
◦ The both processes can be on the one
computer or on different computer but are
connected through computer network.
◦ Communication may be implemented by
two methods either by Shared Memory or
by Message Passing.

37. Operating System Services
(Cont.)
 Error handling
◦ OS constantly remains aware of possible
errors.
◦ OS takes the appropriate action to ensure
correct and consistent computing.

38. Operating System Services
(Cont.)
 Resource Management
◦ OS manages all kind of resources using
schedulers.
◦ CPU scheduling algorithms are used for
better utilization of CPU.

39. Operating System Services
(Cont.)
 Protection
◦ OS ensures that all access to system
resources is controlled.
◦ OS ensures that external I/O devices are
protected from invalid access attempts.
◦ OS provides authentication feature for
each user by means of a password.

40. Operating System Properties
 Batch processing
◦ OS defines a job which has predefined
sequence of commands, programs and data
as a single unit.
◦ OS keeps a number a jobs in memory and
executes them without any manual
information.
◦ Jobs are processed in the order of
submission i.e. first come first served fashion.
◦ When job completes its execution, its
memory is released and the output for the job
gets copied into an output spool for later
printing or processing.

41. Operating System Properties
(Cont.)
 Multitasking
◦ The user gives instructions to the operating system or
to a program directly, and receives an immediate
response.
◦ Operating System handles multitasking in the way
that it can handle multiple operations / executes
multiple programs at a time.
◦ Multitasking Operating Systems are also known as
Time-sharing systems.
◦ These Operating Systems were developed to provide
interactive use of a computer system at a reasonable
cost.
◦ A time-shared operating system uses concept of CPU
scheduling and multiprogramming to provide each
user with a small portion of a time-shared CPU.
◦ Each user has at least one separate program in
memory.

42. Operating System Properties
(Cont.)
◦ A program that is loaded into memory and is executing is
commonly referred to as a process.
◦ When a process executes, it typically executes for only a
very short time before it either finishes or needs to perform
I/O.
◦ Since interactive I/O typically runs at people speeds, it may
take a long time to complete. During this time a CPU can
be utilized by another process.
◦ Operating system allows the users to share the computer
simultaneously. Since each action or command in a time-
shared system tends to be short, only a little CPU time is
needed for each user.
◦ As the system switches CPU rapidly from one
user/program to the next, each user is given the impression
that he/she has his/her own CPU, whereas actually one
CPU is being shared among many users.

43. Operating System Properties
(Cont.)
 Multiprogramming
◦ The operating system keeps several jobs in
memory at a time.
◦ This set of jobs is a subset of the jobs kept in
the job pool.
◦ The operating system picks and begins to
execute one of the job in the memory.
◦ Multiprogramming operating system monitors
the state of all active programs and system
resources using memory management
programs to ensures that the CPU is never
idle unless there are no jobs

44. Operating System Properties
(Cont.)
 Interactivity
◦ OS provides user an interface to interact
with system.
◦ OS managers input devices to take inputs
from the user. For example, keyboard.
◦ OS manages output devices to show
outputs to the user. For example, Monitor.
◦ OS Response time needs to be short
since the user submits and waits for the
result.

45. Operating System Properties
(Cont.)
 Real Time System
◦ In such systems, Operating Systems
typically read from and react to sensor
data.
◦ The Operating system must guarantee
response to events within fixed periods of
time to ensure correct performance.

46. Operating System Properties
(Cont.)
 Distributed Environment
◦ OS Distributes computation logics among
several physical processors.
◦ The processors do not share memory or a
clock.
◦ Instead, each processor has its own local
memory.
◦ OS manages the communications
between the processors. They
communicate with each other through
various communication lines.

47. Thank you