An operating system (OS) is the software that manages the hardware and software resources of a computer. It acts as an intermediary between the computer hardware and the applications that run on the computer. The operating system provides the necessary support and services to run applications, manage memory, handle input/output operations, and perform other tasks. It is the first software that is loaded when the computer starts up, and it runs continuously in the background, providing the necessary resources and services to other programs. Examples of popular operating systems include Windows, macOS, Linux, and Android. The basic functions of an operating system include:
Managing files: An operating system is responsible for managing the file system, organizing files and directories, and providing access to files for both the user and the applications running on the computer. Handling interrupts: The operating system is responsible for handling interrupts generated by hardware components, such as the keyboard or mouse, and ensuring that the computer responds in a timely manner. Providing an interface: The operating system provides a user interface, such as a graphical user interface or command-line interface, allowing the user to interact with the computer and perform tasks. Managing peripherals and drivers: The operating system manages peripheral devices, such as printers and storage devices, and provides drivers to allow the hardware to interact with the software. A graphical user interface (GUI) is a type of user interface that uses graphical elements, such as icons and windows, to allow the user to interact with the computer. A command-line interface (CLI) is a type of user interface that uses text-based commands to perform tasks and access information. A GUI is more user-friendly and easier to use than a CLI, but a CLI provides more control and is more efficient for advanced users. Managing memory: The operating system manages the computer's memory, allocating memory to running applications and managing memory allocation and deallocation as needed. The operating system uses various algorithms, such as first-fit and best-fit, to determine how to allocate memory to running applications, and it also manages the freeing up of memory when applications are closed. Managing multitasking: The operating system is responsible for managing multitasking, allowing multiple applications to run simultaneously and switching between them as needed. Providing a platform for running applications: The operating system provides a platform for running applications, providing the underlying support and resources needed to run the software. Providing system security: The operating system provides security features, such as user authentication, access control, and data encryption, to protect the computer and its data from unauthorized access and attack. The operating system also provides firewalls, antivirus software, and other security tools to prevent unauthorized access and protect against attacks. Managing user accounts: The operating system is responsible for managing user accounts, allowing multiple users to log in and use the computer and managing the permissions and access rights for each user.
SECTION 2 | ALLOCATING RESOURCES
Operating systems deal with allocating storage and keeping track of programs in memory through a variety of techniques, including memory management, swapping, time-slicing, priority scheduling, and input/output operations. Here is a brief description of each of these techniques:
Memory management: Operating systems use memory management techniques to allocate memory to programs as needed. This can include managing the size and location of memory partitions, allocating memory to individual processes, and keeping track of memory usage to prevent over-allocation and system crashes.
Swapping: When a program's memory requirements exceed the available physical memory, the operating system can use swapping to transfer parts of the program from memory to disk storage, freeing up memory for other programs. This process can be automated by the operating system, which can swap out programs that have not been used for a certain amount of time or that are using excessive amounts of memory.
Time-slicing: Time-slicing is a technique used by operating systems to allow multiple programs to share the CPU by dividing its time among them. Each program is given a certain amount of CPU time, typically measured in milliseconds, before the operating system switches to the next program in the queue.
Priority scheduling: Priority scheduling is a technique used by operating systems to give higher priority to certain programs or processes, allowing them to receive more CPU time than lower priority programs. This can be useful for real-time applications or for ensuring that critical tasks are completed quickly.
Input/output operations: Operating systems manage input/output operations by providing programs with access to peripheral devices such as printers, keyboards, and displays. The operating system can allocate resources such as buffers and communication channels to each program and manage the flow of data between the program and the device.
Operating systems use a variety of techniques to allocate storage and manage programs in memory, including memory management, swapping, time-slicing, priority scheduling, and input/output operations. By using these techniques effectively, operating systems can improve system performance, manage resources efficiently, and prevent system crashes and other issues.
SECTION 3 | MULTI TASKING
The operating system handles multiple tasks and to the user they often seem to run seamlessly simultaneously, below are some of the common manage techniques operating systems use:
Scheduling: Scheduling is the process by which an operating system decides which program or process should run next on the CPU. Scheduling algorithms can be based on factors such as priority, time-sharing, and real-time requirements.
Policies: Operating systems can use policies to control how resources are allocated and used by programs and processes. Policies can include limits on memory usage, CPU time, and network bandwidth, as well as rules for handling errors and conflicts.
Multitasking: Multitasking is the ability of an operating system to run multiple programs or processes at the same time. This can be achieved through techniques such as time-sharing, priority scheduling, and parallel processing.
Virtual memory: Virtual memory is a technique used by operating systems to allow programs to use more memory than is physically available on the system. This is achieved by mapping memory addresses used by programs to different areas of physical memory or disk storage.
Paging: Paging is a technique used by operating systems to manage virtual memory by dividing it into fixed-size pages. When a program accesses a page that is not currently in physical memory, the operating system retrieves it from disk storage and places it in memory.
Interrupt: An interrupt is a signal sent to the CPU by a device or program to indicate that it requires attention. The operating system can use interrupt handling to manage input/output operations, respond to hardware failures, and manage system resources.
Polling: Polling is a technique used by operating systems to manage input/output operations by regularly checking the status of devices and peripherals to see if they require attention. This can be less efficient than interrupt handling, but is useful for certain types of devices and systems.
Operating systems use a variety of resource management techniques to manage system resources and ensure that programs and processes run efficiently and reliably. These techniques can include scheduling, policies, multitasking, virtual memory, paging, interrupt handling, and polling. By using these techniques effectively, operating systems can improve system performance, reduce errors and conflicts, and prevent system crashes and other issues.
SECTION 4 | DEDICATED OPERATING SYSTEMS
A dedicated operating system (OS) is an operating system that is designed to run on a specific device or platform. Unlike general-purpose operating systems such as Windows, Linux, or macOS, which are designed to run on a wide range of devices, a dedicated OS is tailored to the specific hardware and software requirements of a particular device or platform.
A dedicated OS can be designed for a variety of devices, including smartphones, tablets, embedded systems, gaming consoles, and other specialized devices. These devices often have specific hardware requirements, such as sensors, touchscreens, and specialized input/output devices, that a dedicated OS can take advantage of.
Optimized performance: A dedicated OS can be designed to take full advantage of the hardware and software capabilities of the device, resulting in faster and more efficient performance. This can be especially important for devices with limited resources, such as smartphones, tablets, and embedded systems.
Improved security: A dedicated OS can be designed with security features that are specific to the device and its intended use. This can include encryption, authentication, and access controls, which can help protect the device and its data from unauthorized access or attacks.
Better user experience: A dedicated OS can be customized to meet the specific needs and preferences of the device's users, resulting in a better user experience. This can include features such as intuitive user interfaces, touchscreens, and voice recognition.
Simplified maintenance and support: A dedicated OS can be easier to maintain and support, as it is designed specifically for the device and its components. This can make it easier for developers to troubleshoot issues, release updates, and provide technical support to users.
Reduced costs: Developing a dedicated OS can be more cost-effective than using a commercial or off-the-shelf OS, especially for high-volume products. This can allow manufacturers to lower the cost of the device and make it more accessible to consumers.
Producing a dedicated OS for a device can offer several advantages, including optimized performance, improved security, better user experience, simplified maintenance and support, and reduced costs. These benefits can make it easier for manufacturers to create devices that meet the specific needs and preferences of their users, while also improving the overall quality and reliability of the device.
However, developing a dedicated OS can also be more time-consuming and expensive than using a commercial or off-the-shelf OS, as it requires specialized expertise and resources. Additionally, a dedicated OS may have limited compatibility with other devices or platforms, which can limit its usefulness for certain applications.
SECTION 5 | HIDING COMPLEXITY
Operating hide the complexity of hardware to the user to make the system more intuitive and user-friendly, some methods they use include:
Virtualization of real devices: An operating system can use virtualization to create virtual devices that mimic the functionality of real hardware devices, such as printers, scanners, and network adapters. This can simplify the programming and use of these devices, as they can be treated as software objects rather than complex hardware components.
Drive letters: An operating system can use drive letters to abstract the complexity of disk storage devices from users and applications. Instead of having to navigate complex file systems, users can access files and folders through a simple drive letter, such as C: or D:.
Virtual memory: An operating system can use virtual memory to provide applications with more memory than is physically available on the system. This allows applications to operate as if they have access to more memory, without requiring them to manage the complexities of physical memory.
Input devices: An operating system can provide a common interface for input devices such as keyboards, mice, and touchscreens. This can abstract the complexities of different input devices from applications, allowing them to receive input in a standard format.
Java Virtual Machine: The Java Virtual Machine (JVM) is a software layer that abstracts the complexities of hardware and operating systems from Java applications. The JVM provides a standardized environment for Java applications to run, regardless of the underlying hardware or operating system.
Operating systems can hide the complexity of hardware from users and applications in a variety of ways, including virtualization of real devices, drive letters, virtual memory, input devices, and the Java Virtual Machine. By abstracting the complexities of hardware, operating systems can simplify the programming and use of devices and resources, making them more accessible to users and developers.