OPERATING SYSTEM

CSC 222

(WINDOWS APPLICATION)

Course Con
 Definition
 Advantage
 Windows
 Componen
Interpreter
 Batch Pro
Multiproc
 Allocation
 Operating
 Input / Ou

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An overview of Operating System-Definition, Types, Uses, Advantages and Disadvantages
Operating System Definition
An operating system (OS) is a collection of software that manages computer hardware resources
and provides common services for computer programs. The operating system is a vital
component of the system software in a computer system.
An operating system (OS) is a complex software that manages computer hardware resources and
provides a platform for running application software
An operating system is a program that acts as an interface between the user and the computer
hardware and controls the execution of all kinds of programs.
An operating system (OS) is a software that manages computer hardware resources and provides
a platform for running application software.
An Operating System (OS) can be defined as a set of computer programs that manage the
hardware and software resources of a computer. It is the core of compute programming that
primarily deals with computer architecture. Operating system is basically an application program
that serves as an interface to coordinate different resources of computer. An operating system
processes raw system and user input and responds by allocating and managing tasks and internal
system resources as a service to users and programs of the system

Types of Operating Systems

With the rapid evolution of technology, various types of operating systems have emerged to cater
to different needs and applications. Here, we will discuss seven types of operating systems. The
various types of operating systems cater to different needs and an application, providing a range
of benefits and capabilities, each type of operating system plays a vital role in enabling modern

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computing. As technology continues to evolve, it is likely that new types of operating systems
will emerge, providing evens more innovative solutions and capabilities.

1. Single-user-single-tasking operating systems allow only one user to run one program at a
time. MS-DOS is a classic example of this type of operating system. This type of operating
system is simple, efficient, and easy to use, but it has limited capabilities and is not suitable
for modern computing needs.
2. Single-user-multi-tasking operating systems allow one user to run multiple programs
simultaneously. Windows and macOS are popular examples of this type of operating
system. This type of operating system provides a high degree of flexibility and
productivity, enabling users to run multiple applications concurrently.
3. Multi-user operating systems allow multiple users to access the computer simultaneously.
Unix and Linux are examples of this type of operating system. This type of operating
system provides a high degree of security, flexibility, and scalability, making it suitable for
large-scale computing environments.
4. Multi-processing operating systems allow multiple processors or cores to be utilized.
Windows Server and Linux are examples of this type of operating system. This type of
operating system provides a high degree of performance, scalability, and reliability,
making it suitable for demanding applications such as scientific simulations, data analytics,
and cloud computing.
5. Real-time operating systems guarantee a predictable and fast response to events. VxWorks
and QNX are examples of this type of operating system. This type of operating system is
designed for applications that require precise timing and control, such as robotics,
automation, and medical devices.
6. Mobile operating systems are designed for mobile devices such as smartphones and tablets.
Android and iOS are popular examples of this type of operating system. This type of
operating system provides a high degree of portability, flexibility, and usability, enabling
users to access a wide range of applications and services on the go.
7. Embedded operating systems are designed for embedded systems such as traffic lights,
appliances, and industrial control systems. This type of operating system provides a high
degree of reliability, efficiency, and security, enabling it to operate in harsh environments
and meet strict performance requirements.

The Uses of Operating Systems

One of the primary functions of an operating system is to manage the various components of a
computer system, ensuring that they work together efficiently and effectively. We shall discuss
six key uses of operating systems: process management, memory management, file system
management, input/output (I/O) management, security, and networking.
1. Operating systems are responsible for process management, which involves managing the
creation, execution, and termination of processes. Process management ensures that
multiple processes can run concurrently, improving system performance and
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 responsiveness e.g. scheduling. For instance, a user can run multiple applications
simultaneously, such as a web browser, email client, and word processor, without
experiencing significant performance degradation.
2. Operating systems manage memory allocation and deallocation, ensuring that memory is
used efficiently and effectively. Memory management involves allocating memory to
running programs, deallocating memory when programs terminate, and managing memory
fragmentation. Effective memory management prevents memory-related errors, reduces
crashes, and improves overall system performance.
3. Operating systems provide a file system to store and retrieve data. File system management
involves creating, deleting, and managing files and directories. Operating systems use
various file systems, such as FAT, NTFS, and ext4, to manage files and directories. File
system management ensures that files are stored and retrieved efficiently, and that data is
protected from corruption and loss.
4. Operating systems manage input/output (I/O) operations between devices. I/O management
involves managing data transfer between devices, such as keyboards, mice, printers, and
disk drives. Operating systems use various I/O management techniques, such as buffering
and caching, to optimize data transfer. Effective I/O management improves system
performance, reduces latency, and enhances user experience.
5. Operating systems provide mechanisms for controlling access to computer resources,
ensuring security and integrity. Security involves managing access control, authentication,
and authorization. Operating systems use various security mechanisms, such as access
control lists, firewalls, and encryption, to protect against security threats. Effective security
management prevents unauthorized access, reduces the risk of data breaches, and protects
against malware and other security threats.
6. Operating systems manage communication between computers, enabling networking and
communication. Networking involves managing data transfer between computers, ensuring
that data is transmitted efficiently and reliably. Operating systems use various networking
protocols, such as TCP/IP and HTTP, to manage communication between computers.
Effective networking management enables communication, collaboration, and resource
sharing between computers.

APPLICATION OF OPERATING SYSTEM

The operating system is used everywhere today, such as banks, schools, hospitals, companies,
mobiles, etc. No device can operate without an operating system because it controls all the user's
commands.
 LINUX/UNIX operating system is used in the bank because it is a very secure operating
system.
 Symbian OS, Windows Mobile, iOS, and Android OS are used in mobile phone
operating systems as these operating systems are a lightweight operating system.
Needs of Operating System

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The following points indicate the need for the operating system:
o More than one program runs at a time in a computer, and all of them require your
computer's CPU and memory. The operating system manages resources for all those
programs. That is why the operating system is required.
o Multitasking is a very critical feature of the OS. With its help, we can run many programs
simultaneously.
o The operating system provides a platform to run any application program in the
computer. Due to which we can do our work with the help of that application.
o It helps the user in file management. Through this, the user can save the data according to
his needs.
o You use your mouse to open the application and click on the menu. All this is possible
due to the modern operating system. This operating system allows you to do this with the
help of GUI (Graphical user interface).
o The operating system creates a communication link between the user and the computer,
allowing the user to run any application program and obtain the required output properly.
o It is almost impossible for a user to use a computer system without an operating system.
Many processes run simultaneously when a program is executed, which is not easy for a
person to manage.

The Advantages of Operating Systems

Operating systems offer numerous advantages that make them an essential component of modern
computing. Here, we shall discuss five significant advantages of operating systems: hardware
abstraction, multi-tasking, memory management, security, and portability.

1. One of the primary advantages of operating systems is hardware abstraction. Operating

systems provide a layer of abstraction between hardware and user, allowing users to
interact with the computer without worrying about the underlying hardware. This
abstraction layer enables users to write programs that can run on different hardware

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 platforms, without modifying the code. For instance, a program written for a Windows
operating system can run on different hardware configurations, such as laptops, desktops,
or servers, without requiring significant modifications. Hardware abstraction simplifies
the development process, reduces costs, and increases productivity.
2. Another significant advantage of operating systems is multi-tasking. Operating systems
allow multiple tasks to be performed simultaneously, improving productivity and
efficiency. Multi-tasking enables users to run multiple applications concurrently, such as
browsing the internet, editing documents, and listening to music. Multi-tasking enhances
the overall computing experience, making it more efficient and enjoyable.
3. Operating systems also provide efficient memory management, which is essential for
modern computing. Memory management involves allocating and deallocating memory
for running programs, ensuring that memory is used efficiently and effectively. Efficient
memory management prevents memory-related errors, reduces crashes, and improves
overall system performance.
4. Operating systems provide Security. It provide mechanisms for controlling access to
computer resources, ensuring that unauthorized users cannot access sensitive data or
disrupt system operations. Operating systems use various security mechanisms, such as
access control lists, firewalls, and encryption, to protect against security threats.
5. Operating systems provide portability, allowing software to be run on different hardware
platforms. Portability enables software developers to write programs that can run on
multiple operating systems and hardware configurations, without requiring significant
modifications. For instance, a program written for a Windows operating system can run
on a Linux or macOS operating system, without requiring significant changes.

In summary, advantages of Operating Systems

1. Hardware Abstraction: Provides a layer of abstraction between hardware and user.
2. Multi-Tasking: Allows multiple tasks to be performed simultaneously.
3. Memory Management: Efficiently manages memory allocation and deallocation.
4. Security: Provides mechanisms for controlling access to computer resources.
5. Portability: Allows software to be run on different hardware platforms.

The Disadvantages of Operating Systems

While operating systems offer numerous benefits, they also have several disadvantages. Here, we
shall discuss five significant disadvantages of operating systems: complexity, vulnerability to
attacks, compatibility issues, cost and resource intensiveness,
1. One of the primary disadvantages of operating systems is their complexity. Installing,
configuring, and managing an operating system can be a discouraging task, especially for
novice users. The complexity of operating systems can lead to frustration, wasted time,
and even system crashes.
2. Operating systems are also vulnerable to attacks from malware, viruses, and other
security threats. The complexity of operating systems can make them more susceptible to
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 security vulnerabilities, which can be exploited by malicious actors. For instance, a single
vulnerability in an operating system can allow hackers to gain unauthorized access to
sensitive data or take control of the system. This can have serious consequences,
including data breaches, identity theft, and financial losses.
3. Compatibility issues are another significant disadvantage of operating systems. Operating
systems can have compatibility issues with hardware and software, which can lead to
system crashes, errors, or failed installations. For example, a new operating system may
not be compatible with older hardware or software, requiring users to upgrade or replace
their existing hardware or software. This can be costly and time-consuming, especially
for users who rely on specific software or hardware for their work or daily activities.
4. Operating systems can be expensive to purchase and maintain. While some operating
systems are free or open-source, many commercial operating systems require a
significant upfront cost or subscription fee. Additionally, maintaining an operating
system can require on-going costs, including updates, and technical support. For instance,
businesses may need to purchase multiple licenses for their employees, which can be
costly. Individuals may also need to purchase separate licenses for their personal devices.
5. Another significant disadvantage of operating systems is their resource intensiveness.
Modern operating systems require significant hardware resources, including processing
power, memory, and storage. This can lead to slower system performance, especially on
older hardware or devices with limited resources. For example, running multiple
resource-intensive applications simultaneously can cause the system to slow down or
even freeze. This can be frustrating for users who need to multitask or run demanding
applications.

In conclusion, as operating systems continue to evolve, it is essential for developers to address

these disadvantages and provide users with more efficient, secure, and user-friendly operating
systems.

In summary, disadvantages of Operating Systems

1. Complexity: Can be complex to install, configure, and manage.
2. Vulnerability to Attacks: Can be vulnerable to malware and other security threats.
3. Compatibility Issues: Can have compatibility issues with hardware and software.
4. Cost: Can be expensive to purchase and maintain.
5. Resource Intensive: Requires significant hardware resources.
The Components of Operating Systems: Assemblers, Compilers, and Interpreters
One of the key components of an operating system is the programming language translator,
which includes assemblers, compilers, and interpreters. These components play a crucial role in
translating programming languages into machine code that the computer's processor can execute.
Understanding the role of these components in operating systems is essential for computer
science students, programmers, and software developers.

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 1. Assemblers are a type of programming language translator that translates assembly
language into machine code. Assembly language is a low-level programming language
that uses symbolic codes to represent machine-specific instructions. Assemblers take the
assembly language code as input and generate machine code as output. This process
involves substituting symbolic codes with their corresponding machine codes and
generating object code that can be executed by the computer.

2. Compilers are another type of programming language translator that translates an entire
high-level programming language into machine code. High-level programming
languages, such as C, C++, and Java, are easier to learn and use than assembly language,
but they need to be translated into machine code before they can be executed by the
computer. Compilers take the high-level programming language code as input and
generate machine code as output.

3. Interpreters are a type of programming language translator that translates high-level

programming languages into machine code line by line. Unlike compilers, which
translate the entire program into machine code before executing it, interpreters translate
and execute the program line by line. This makes interpreters more flexible and
interactive than compilers, but also slower and less efficient. Interpreters are commonly
used for scripting languages, such as Python and JavaScript, and for interactive
programming environments, such as debuggers.

In conclusion, assemblers, compilers, and interpreters are essential components of operating

systems that enable the translation of programming languages into machine code. Each of these
components plays a crucial role in the programming language translation process, and they are
used in different contexts and applications. Assemblers are used for low-level programming,
compilers are used for high-level programming, and interpreters are used for scripting and
interactive programming.

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The Evolution of Computer Processing explore four major examples: batch processing,
real-time processing, time-sharing processing, and multi-processing.

Computers are amazing machines that can perform a wide range of tasks, from simple
calculations to complex simulations. However, have you ever wondered how computers manage
to do all these tasks? The answer lies in the way computers process information, which can be
broadly classified into four categories: batch processing, real-time processing, time-sharing
processing, and multi-processing. In this essay, we will explore each of these concepts in simple
terms.

Batch Processing: Doing Things in Batches

Imagine you have a large stack of
papers that need to be stapled. Instead of
stapling each paper individually, you
can staple them in batches. This is
similar to how batch processing works.
In batch processing, a computer
performs a series of tasks, one after the
other, without any human intervention.
The computer is given a set of
instructions, and it executes them in a
sequence, without stopping or waiting for user input. Batch processing is commonly used for
tasks like payroll processing, data backups, and report generation.

Real-Time Processing: Instant Results

Now, imagine you are playing a video game, and you need to react quickly to avoid obstacles. In
this scenario, you need instant feedback from the computer. This is where real-time processing
comes in. Real-time processing involves processing data instantly, without any delay. The
computer receives input, processes it immediately, and provides output in real-time. Real-time
processing is critical in applications like air traffic control, medical devices, and financial trading
platforms.

Time-Sharing Processing: Sharing Computer Time

Picture a scenario where multiple people need to use a

computer at the same time. Time-sharing processing allows
multiple users to share the computer's resources, like
memory and processing power. The computer allocates a
specific time slot to each user, allowing them to work on

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their tasks simultaneously. Time-sharing processing is commonly used in cloud computing,
online banking, and social media platforms.

Multi-Processing: Doing Multiple Things at Once

Finally, imagine you are working on a project that requires you to perform multiple tasks
simultaneously, like typing a document, browsing the internet, and listening to music. Multi-
processing allows computers to perform multiple tasks concurrently, improving overall
productivity. The computer's processor is divided into multiple cores, each handling a separate
task. Multi-processing is commonly used in applications like video editing, scientific
simulations, and gaming.

Allocation and scheduling resource

Allocation refers to assigning resources to tasks or processes. Think of it like assigning rooms in
a hotel. While scheduling refers to deciding when and how to allocate resources to tasks or
processes. Think of it like managing a restaurant’s reservations. When it comes to operating
systems, resource allocation and scheduling are key functions that ensure the smooth running of
the system.
In the realm of computer science, the efficient management of resources is crucial for optimal
system performance. Two fundamental concepts that facilitate this efficiency are allocation and
scheduling of resources. Allocation refers to the assignment of resources to tasks or processes,
while scheduling determines when and how these resources are allocated. In this essay, we will
delve into the processes of allocation and scheduling, exploring their components, algorithms,
and significance in ensuring the smooth operation of computational systems.

The allocation of resources is a multifaceted process that begins with resource identification.
This involves recognizing the available resources within a system, such as CPU, memory, and
I/O devices. Once these resources are identified, the next step is resource allocation, where
resources are assigned to tasks or processes based on factors like priority, need, and availability.
This allocation must be judicious to prevent resource starvation, where a task is perpetually
denied access to the resources it needs. Finally, resource deallocation occurs when tasks or
processes complete or are terminated, allowing resources to be reclaimed and reassigned.

Scheduling resources is equally critical and involves deciding when and how to allocate
resources to tasks or processes. This can be further divided into job scheduling, process
scheduling, and resource scheduling. Job scheduling involves scheduling tasks or processes
(jobs) based on priority, deadlines, and resource availability. Process scheduling, on the other
hand, focuses on scheduling processes (programs in execution) based on factors like CPU usage,
I/O operations, and memory requirements. Resource scheduling manages access to shared
resources such as printers, scanners, or network devices.

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To achieve efficient scheduling, various algorithms are employed. Some common scheduling
algorithms include:
1. First-Come-First-Served (FCFS): Schedule tasks in the order they arrive.
2. Shortest Job First (SJF): Schedule the shortest task first.
3. Priority Scheduling: Schedule tasks based on priority. Where the operating system
prioritizes certain processes over others based on their importance.
4. Round Robin (RR): Where the operating system gives each process a "slice" of time to
run. This ensures that no single process monopolizes the system's resources.
5. Shortest Remaining Time First (SRTF). This algorithm prioritizes processes based on
how much time they have left to run. So if two processes have the same priority, the one
that will finish the soonest will be scheduled first.
6. Multilevel feedback queue (MLFQ), which uses a hierarchy of queues to prioritize
processes. The scheduler uses information about each process, such as its priority and
how much time it has used, to decide which queue to put it in.
7. Fair-share scheduling. This algorithm prioritizes processes based on their "fair share" of
the system's resources. So if one process has used a lot of the system's resources, it will
be de-prioritized so that other processes can have a fair chance to run. This algorithm is
often used in virtualized environments, where multiple operating systems share the same
physical hardware.

OPERATING SYSTEM NUCLEUS AND MEMORY MANAGEMENT

The Operating System Nucleus: The Heart of the Operating System
The operating system nucleus, also known as the kernel, is the central part of an operating
system (OS). It is the most fundamental component of the OS, responsible for managing the
system's hardware resources and providing basic services to applications. In this essay, we will
explore the operating system nucleus, its functions, and its importance.

Functions of the Operating System Nucleus:

1. Process Management: The nucleus manages the creation, execution, and termination of
processes (programs) running on the computer.
2. Memory Management: It manages the allocation and deallocation of memory for running
programs.
3. File System Management: The nucleus provides access to the file system, allowing
programs to read and write files.
4. Input/Output (I/O) Management: It manages input/output operations between devices
such as keyboards, displays, and printers.
5. Security: The nucleus provides mechanisms for controlling access to computer resources,
such as user authentication and access control.
6. Interrupt Handling: It handles interrupts generated by hardware devices, such as keyboard
presses or disk completion.

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 7. Resource Allocation: The nucleus manages the allocation and deallocation of system
resources, such as CPU time, memory, and I/O devices.

Importance of the Operating System Nucleus:

1. Efficient Resource Utilization: The nucleus ensures efficient use of system resources,
such as CPU time and memory.
2. Security and Protection: It provides mechanisms for controlling access to computer
resources, ensuring security and protection.
3. Portability: The nucleus allows operating systems to be portable across different
hardware platforms.
4. Extensibility: It provides a framework for adding new features and functionality to the
operating system.
5. Performance: The nucleus plays a critical role in ensuring the performance and
responsiveness of the operating system.

In conclusion, the operating system nucleus is the heart of the operating system, responsible for
managing hardware resources and providing basic services to applications. Its functions and
importance make it a critical component of modern computer systems.

Memory management
Memory management is the process of allocating and de-allocating memory to processes and
keeping track of which memory is in use and which is available. The operating system's memory
manager is responsible for this. It uses a variety of techniques to manage memory, such as
paging, segmentation, and swapping.
 Paging is a technique that breaks up the memory into small, fixed-sized blocks called
pages. The memory manager keeps track of which pages are in use and can load and
unload them from memory as needed.
 Segmentation breaks the memory into logical segments based on the process that's using
it. Segmentation allows the operating system to share the physical memory between
multiple processes, even if they're all using different logical addresses.
 Swapping is a technique where the memory manager moves inactive pages of memory to
a disk, so they are not taking up valuable physical memory. This allows the system to
have more memory available for active processes.
 The memory manager also keeps track of which pages of memory are shared between
processes. This is called copy-on-write. So, there's a lot going on behind the scenes to
manage the system's memory!
So, let us discuss about memory allocation requests from processes. There are two main types of
requests: static and dynamic.

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  Static requests are made at compile time and don't change during the lifetime of the
process.
 Dynamic requests are made at runtime and can change as the process runs.
The memory manager keeps track of these requests and tries to meet them as best as possible. It
does this by using a variety of algorithms, such as best-fit, first-fit, and worst-fit. These
algorithms have different trade-offs in terms of efficiency and performance.
Best-Fit Algorithm.
This algorithm tries to find the smallest block of memory that can satisfy the request. This is the
most efficient use of memory, but it can take a long time to search through all the possible
blocks.
First-Fit Algorithm
The algorithm tries to find the first block of memory that can satisfy the request. This is faster
than best-fit, but it can waste more memory. The worst-fit algorithm tries to find the largest block
of memory that can satisfy the request. This can be slow, but it minimizes memory wastage.
Worst-fit algorithm
Worst-fit is generally considered the most effective of the three algorithms. It's slower than the
others, but it minimizes memory wastage and fragmentation. Fragmentation occurs when there
are many small, unused blocks of memory scattered throughout the system. This can lead to
memory shortages, even when there's enough total memory available. Worst-fit helps to reduce
this problem by trying to allocate the largest possible block of memory. So, worst-fit is slower,
but it's more efficient in the long run.
INPUT/OUTPUT SYSTEM
Input systems
An input system is a subsystem of the operating system that handles user input. This includes
devices like keyboards, mice, and touchscreens. The input system is responsible for translating
the raw data from these devices into something that the operating system can understand. This is
done by an input driver, which is a program that communicates with the device and converts the
data into a standard format. The input system also handles things like user authentication, so only
authorized users can access the system.
One important part of the input system is called the interrupt handler. This is a piece of code
that's triggered whenever an input device sends an interrupt signal. An interrupt signal is sent
when a device needs the operating system's attention, such as when a key is pressed or a mouse
button is clicked. The interrupt handler decides what to do with the interrupt, and it sends the
data to the appropriate process. This allows the input system to handle multiple input devices at
the same time.

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Interrupts come in two flavors: hardware interrupts and software interrupts.
 A hardware interrupt is triggered by an external device, like a mouse or keyboard.
 A software interrupt is triggered by the operating system itself. For example, when the
operating system needs to schedule a process, it will send a software interrupt to the
processor. This causes the processor to stop what its doing and handle the interrupt.
Interrupts are a vital part of the input system, as they allow the system to respond quickly
to input from the user.
Output systems
Output systems are the part of the operating system that handles outputting information to the
user. This includes things like printing, displaying images on the screen, and playing sounds. The
output system also includes the output driver, which is the program that sends the output to the
appropriate device. For example, the output driver for the display will send the image data to the
monitor. The output system is closely integrated with the input system, so they can work together
to provide a seamless user experience.
Let's start with one of the most important parts of the output system: The display driver. This is a
program that translates the graphics commands from the operating system into signals that the
monitor can understand. It also handles tasks like refreshing the screen and rendering 3D
graphics. Without the display driver, the monitor would just be a blank screen! Another
important part of the output system is the audio driver, which sends sound data to the speakers or
headphones. It also manages tasks like encoding and decoding audio data.
One example of an output system is a printer. The printer driver is the program that sends data to
the printer. It also handles tasks like converting the data into a format that the printer can
understand. Another example is the Graphics Processing Unit (GPU). The GPU is a specialized
chip that handles rendering 3D graphics. It's often used in gaming, as it can render complex
images very quickly. The GPU also helps to speed up other tasks that involve complex graphics,
like video editing.
 Another important part of the output system is the Universal Serial Bus (USB) driver.
This driver manages the USB ports on the computer. It allows you to connect a variety of
devices, like printers, cameras, and keyboards. It also handles tasks like power
management and data transfer. Without the USB driver, you will not be able to use all of
the devices that rely on USB.
 Another example is the serial port driver, which handles data transfer over serial ports.
Serial ports are used to connect devices like modems and scanners.

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