Introduce

the
Functions of
Operating
System
I T A P P L I C AT I O N T O O L S I N
BUSINESS
Functions of Operating System
Operating System
An operating system (OS) is a program that acts as an interface between the
system hardware and the user. Moreover, it handles all the interactions
between the software and the hardware. All the working of a computer
system depends on the OS at the base level. Further, it performs all the
functions like handling memory, processes, the interaction between
hardware and software, etc. Now, let us look at the functions of operating
system.
Operating System
Objectives of OS
The primary goals of an operating system are as follows:
Convenience – An operating system improves the use of a machine. Operating
systems enable users to get started on the things they wish to complete quickly
without having to cope with the stress of first configuring the system.
Efficiency – An operating system enables the efficient use of resources. This is due
to less time spent configuring the system.
Ability to evolve – An operating system should be designed in such a way that it
allows for the effective development, testing, and introduction of new features
without interfering with service.
Management of system resources – It guarantees that resources are shared fairly
among various processes and users.
Functions of Operating System

1. Memory Management
2. Processor Management/Scheduling
3. Device Management
4. File Management
5. Storage Management
1. Memory Management
It is the management of the main or primary memory. Whatever program is
executed, it has to be present in the main memory. Main memory is a quick
storage area that may be accessed directly by the CPU. When the program is
completed, the memory region is released and can be used by other
programs. Therefore, there can be more than one program present at a time.
Hence, it is required to manage the memory.
1. Memory Management
The operating system:
1. Allocates and deallocates the memory.
2. Keeps a record of which part of primary memory is used by whom and
how much.
3. Distributes the memory while multiprocessing.
4. In multiprogramming, the operating system selects which processes
acquire memory when and how much memory they get.
2. Processor Management/Scheduling
Every software that runs on a computer, whether in the background or in the
frontend, is a process. Processor management is an execution unit in which a
program operates. The operating system determines the status of the
processor and processes, selects a job and its processor, allocates the
processor to the process, and de-allocates the processor after the process is
completed.
2. Processor Management/Scheduling
When more than one process runs on the system the OS decides how and
when a process will use the CPU. Hence, the name is also CPU Scheduling.
The OS:
1. Allocates and deallocates processor to the processes.
2. Keeps record of CPU status.
2. Processor Management/Scheduling
Certain algorithms used for CPU scheduling are as follows:
1. First Come First Serve (FCFS)
2. Shortest Job First (SJF)
3. Round-Robin Scheduling
4. Priority-based scheduling etc.
3. Device Management
An operating system regulates device connection using drivers. The
processes may require devices for their use. This management is done by the
OS. The OS:
1. Allocates and deallocates devices to different processes.
2. Keeps records of the devices.
3. Decides which process can use which device for how much time.
4. File Management
The operating system manages resource allocation and de-allocation. It
specifies which process receives the file and for how long. It also keeps track
of information, location, uses, status, and so on. These groupings of
resources are referred to as file systems. The files on a system are stored in
different directories. The OS:
1. Keeps records of the status and locations of files.
2. Allocates and deallocates resources.
3. Decides who gets the resources.
5. Storage Management
Storage management is a procedure that allows users to maximize the
utilization of storage devices while also protecting data integrity on whatever
media on which it lives. Network virtualization, replication, mirroring, security,
compression, deduplication, traffic analysis, process automation, storage
provisioning, and memory management are some of the features that may
be included.
The operating system is in charge of storing and accessing files. The
creation of files, the creation of directories, the reading and writing of data
from files and directories, as well as the copying of the contents of files and
directories from one location to another are all included in storage
management.
5. Storage Management
The OS uses storage management for:
1. Improving the performance of the data storage resources.
2. It optimizes the use of various storage devices.
3. Assists businesses in storing more data on existing hardware, speeding
up the data retrieval process, preventing data loss, meeting data retention
regulations, and lowering IT costs
What are the functions of Operating System?
Security – For security, modern operating systems employ a firewall. A
firewall is a type of security system that monitors all computer activity and
blocks it if it detects a threat.
Job Accounting – As the operating system keeps track of all the functions of
a computer system. Hence, it makes a record of all the activities taking place
on the system.
Control over system performance – The operating system will collect
consumption statistics for various resources and monitor performance
indicators such as reaction time, which is the time between requesting a
service and receiving a response from the system.
What are the functions of Operating System?
Control over system performance – The operating system will collect
consumption statistics for various resources and monitor performance
indicators such as reaction time, which is the time between requesting a
service and receiving a response from the system.

Error detecting aids – While a computer system is running, a variety of errors

might occur. Error detection guarantees that data is delivered reliably across
susceptible networks. The operating system continuously monitors the
system to locate or recognize problems and protects the system from them.
Need for Operating System
1. Interface between the user and the computer
An OS provides a very easy way to interact with the computer. It provides
different features and GUI so that we can easily work on a computer. We have
to interact just by clicking the mouse or through the keyboard. Thus, we can
say that an OS makes working very easy and efficient.
2. Booting
Booting is basically the process of starting the computer. When the CPU is
first switched ON it has nothing inside the memory. So, to start the computer,
we load the operating system into the main memory. Therefore, loading the
OS to the main memory to start the computer is booting. Hence, the OS
helps to start the computer when the power is switched ON.
Need for Operating System
3. Managing the input/output devices
The OS helps to operate the different input/output devices. The OS decides
which program or process can use which device. Moreover, it decides the
time for usage. In addition to this, it controls the allocation and deallocation
of devices.
4. Multitasking
The OS helps to run more than one application at a time on the computer. It
plays an important role while multitasking. Since it manages memory and
other devices during multitasking. Therefore, it provides smooth multitasking
on the system.
Need for Operating System
5. Platform for other application software
Users require different application programs to perform specific tasks on the
system. The OS manages and controls these applications so that they can
work efficiently. In other words, it acts as an interface between the user and
the applications.
Real-Time Operating System (RTOS)
A real-time operating system (RTOS) is a type of operating system. An
operating system is basically, a program that acts as an interface between the
system hardware and the user. Moreover, it handles all the interactions
between the software and the hardware.
The real-time operating systems are used in real-time systems where the
time constraints are fixed and followed strictly. This means that the time for
processing and responding is very small. Moreover, the system should
perform the given task in a fixed time otherwise, it results in a system failure.
Response Time is the time within which the system takes the input,
processes the data, and gives the results. Moreover, they are used in systems
like robots, missile launches, airplanes, etc.
Types of RTOS
1. Hard Real-Time Systems
In this, the time constraint is very short and strict. Even seconds of delay is not
acceptable. Therefore, it is compulsory to complete the task within the given
time only.

Examples: Airplanes systems, Medical treatment systems, etc.

Types of RTOS
2. Firm Real-Time Systems
In these systems, although the deadline is given but, missing them does not
result in great loss. There can be some unwanted side effects in the system if
the deadline is not followed.

Examples: multimedia systems.

Types of RTOS
3. Soft Real-Time Systems
As the name suggests, the system handles the deadlines softly. This means
that if there are small delays in the system, it is acceptable.

Examples: Online Transaction systems, Livestock price quotation systems,

Computer games, etc.
Difference Between Hard and Soft Real-Time Systems

Hard Real-Time System Soft Real-Time System

These systems have to follow the These systems have fewer

deadline very strictly. restrictions on the deadline.

The size of the data file is either On the other hand, soft real-time
small or medium. systems have large data files.

The response time is in Comparatively, the response time

milliseconds. is higher.
Difference Between Hard and Soft Real-Time Systems

Hard Real-Time System Soft Real-Time System

These systems strictly emphasize Safety is not so strict in these

safety. systems.

Examples are satellite launch

Examples are computer games,
systems, missile launch systems,
online transaction systems, etc.
Railway systems, etc
Parts/Components of RTOS
1. Scheduler
It decides the order in which the tasks will execute. Moreover, it decides the
order based on the priority of each task.
2. Memory Management
It allocates memory to every program. Hence, it is one of the most important
elements of the system.
3. Symmetric Multiprocessing (SMP)
It is the multiple different tasks that an RTOS can handle inorder to perform
parallel processing.
Parts/Components of RTOS
4. Function Library
It helps to send the requests from the kernel to the application to produce
the output, using the function library. Thus, it is an interface between the
kernel and the application code.
5. Fast Dispatch Latency
It is the interval between the termination of one task and the starting of
execution of another ‘ready’ state task.
6. User-defined data objects and classes
RTOS makes use of programming languages like C, C++, etc. that are
organized with respect to their operations. The user should define object sets
to organize them. The system uses these sets to control the application.