🎼Операційні системи

1. Introduction to Operating Systems:

• Understanding the role of operating systems.

  • What is an Operating System?: An operating system is a software that manages computer hardware and software resources and provides common services for computer programs. It acts as an intermediary between the user and the computer hardware, allowing users to interact with the computer and run applications. Want to know more?: You can search for "What is an Operating System?" for more information.

  • Windows, Linux, macOS: These are different operating systems that are commonly used on computers. Windows is a popular operating system developed by Microsoft, while Linux is an open-source operating system that is available in various distributions, such as Ubuntu and Fedora. macOS is the operating system used on Apple Mac computers. Want to know more?: If you want to learn more about Windows, Linux, or macOS, you can search for each operating system to find detailed information.

  • Linux distributions: Linux distributions are variations of the Linux operating system that come with different software packages and configurations. Some popular Linux distributions include Ubuntu, Fedora, and Debian. Each distribution has its own unique features and target audience. Want to know more?: You can search for "Linux distributions" to explore different options and learn more about each distribution.

  • Is Linux just a core? Does it have a user interface in its basic core? Linux is more than just a core. It is an operating system that consists of the Linux kernel (the core) and additional software packages that make up a complete operating system. Linux distributions, such as Ubuntu and Fedora, come with a user interface in their basic core, allowing users to interact with the system through graphical interfaces. However, Linux can also be used in server environments without a graphical user interface, where it is controlled through a command-line interface. Want to know more? Google these points: Linux distributions, Linux graphical user interface, Linux command-line interface

  • macOS is based on FreeBSD, similar to Linux: macOS, the operating system used on Apple Mac computers, is built on a foundation called Darwin. Darwin is based on the FreeBSD operating system, which is similar to Linux in terms of being a Unix-like operating system. This means that macOS shares some similarities with Linux in terms of its underlying architecture and command-line interface. Want to know more?: If you are interested in the relationship between macOS, FreeBSD, and Linux, you can search for more information on these topics.

  • Running Linux on Windows. WSL?: Windows Subsystem for Linux (WSL) is a compatibility layer in Windows 10 and Windows Server that enables users to run Linux distributions natively on Windows, without the need for a separate virtual machine. WSL allows you to access Linux tools and utilities directly from the Windows command-line interface. Want to know more?: If you want to learn more about running Linux on Windows using WSL, you can search for "Windows Subsystem for Linux" or "WSL" for more information.

• How does Operating System work? What are the main components of computer and how is this related to OS? An operating system works as a software that manages the hardware and software resources of a computer. It acts as an intermediary between the user and the computer hardware, allowing users to interact with the computer and run applications. The main components of a computer include the central processing unit (CPU), memory (RAM), storage devices (hard drive, SSD), and input/output devices (keyboard, mouse, monitor). The operating system interacts with these components to perform tasks such as managing memory, scheduling processes, handling input/output operations, and providing a user interface.

  • Real life examples

    • Think of an operating system as the conductor of an orchestra, coordinating and managing all the instruments (hardware) to create beautiful music (run applications) for the audience (users).

    • Imagine the operating system as the captain of a ship, guiding and coordinating the crew (hardware) to ensure smooth sailing (execution of tasks) and providing navigation instructions (user interface) to reach the destination (complete tasks).

    • It's like the human brain (hardware) with long and short-term memory. The basic operating system (core, BIOS) is what you have when you are born. Everything else is like installable software that is stored in your long-term memory. Skills are like launching memorized software from long-term memory into short-term memory and executing it using the core of your brain (CPU) and your body (other hardware).

  • Examples related to the topic

    • When you click on an application icon and it opens on your computer, the operating system is responsible for loading the application into memory, allocating resources, and managing the execution of the program.

    • The operating system controls the interaction between a printer and your computer. It receives the print request, manages the data transfer, and sends the appropriate commands to the printer.

  • Want to know more? Google these points:

    • CPU scheduling algorithms

    • Virtual memory management

    • Device drivers

• What are the main components of operating system?

  1. Kernel: The kernel is the core component of an operating system that manages the system's resources and provides essential services. It controls the execution of processes, manages memory, handles input/output operations, and facilitates communication between hardware and software components.

  2. Process Management: The operating system oversees the creation, execution, and termination of processes. It allocates system resources, schedules processes for execution, and ensures proper synchronization and communication among them.

  3. Memory Management: This component is responsible for managing the computer's memory resources. It allocates memory to processes, tracks and updates memory usage, and handles memory-related operations such as loading and unloading programs into memory.

  4. File System: The file system manages the organization, storage, and retrieval of data on storage devices such as hard drives. It provides a hierarchical structure for organizing files and directories and implements access controls and permissions for data security.

  5. Device Drivers: Device drivers enable the operating system to communicate and interact with hardware devices such as printers, keyboards, and network adapters. They provide an interface for the operating system to control and utilize the functionalities of these devices.

1. File Systems:

   • File organization and storage.

     • disks

     • volumes

     • mounting

   • File permissions and security.

     • file access

2. Processes and Threads:

   • Differences between processes and threads.

   • Process scheduling and synchronization.

3. Memory Management:

   • Virtual memory: Virtual memory is a memory management technique used by operating systems to provide the illusion of having more physical memory than is actually available. It allows the computer to use a portion of the hard disk as an extension of RAM, enabling the system to run more programs simultaneously. When the physical memory (RAM) becomes full, the operating system transfers less frequently used data from RAM to the hard disk, freeing up memory for other processes. This process is transparent to the user and helps improve overall system performance.

     • Real life examples

       • Imagine you are working on a project with limited desk space. Instead of keeping all the materials on your desk, you store some of them in a nearby cabinet. When you need them, you can retrieve them from the cabinet and place them on your desk. This way, you can work with more materials without cluttering your workspace.

     • Examples related to the topic

       • When you have multiple applications running on your computer, virtual memory allows the operating system to allocate memory to each program based on its needs. If one program requires more memory than is physically available, the operating system can temporarily store some of its data on the hard disk and retrieve it when needed.

     • Want to know more? Google these points:

       • Paging and swapping in virtual memory

       • Page fault and page replacement algorithms

       • Memory hierarchy and caching

     • Later we'll discuss

       • Memory fragmentation

       • Thrashing in virtual memory systems

       • Memory management unit (MMU)

   • Memory allocation and deallocation: Memory allocation is the process of reserving a portion of the computer's memory for a program or process to use. It involves assigning memory addresses and allocating the necessary space for storing data. Memory deallocation, on the other hand, is the process of freeing up memory that is no longer needed by a program or process, making it available for other purposes.

   • Real life examples

     • Allocating space on a bookshelf to store a collection of books and then removing books that are no longer needed to free up space.

     • Renting a storage unit to store belongings and later returning the unit when the items are no longer needed.

   • Examples related to the topic

     • Allocating memory for a variable in a programming language like C, and then releasing that memory using the free() function when it is no longer needed.

     • Allocating memory for a dynamic array and resizing or deallocating the memory as the size of the array changes.

   • Want to know more? Google these points:

     • Dynamic memory allocation in programming languages

     • Memory management techniques like garbage collection

   • Later we'll discuss

     • Memory fragmentation

     • Memory leaks in programming

     • Memory pools and memory allocators

4. Networking:

   • Basics of Computer Networks: Computer networks are systems that connect multiple computers and devices to enable communication and data sharing. They allow devices to exchange information and collaborate. Computer networks can be wired or wireless and can vary in size, from small local networks in homes and offices to large-scale networks connecting multiple locations globally.

   • Real life examples

     • Computer clubs with offline games.

     • In a company, employees use a local network to share files and communicate with each other.

     • The internet is a global network that connects people from all over the world, allowing them to access information and communicate.

   • Examples related to the topic

     • When you send an email to a friend, your email client uses a network connection to send the message to the recipient's email server.

     • Online gaming relies on computer networks to enable players to connect and play together.

   • Want to know more? Google these points:

     • Types of computer networks (LAN, WAN, MAN)

     • Network protocols (TCP/IP, HTTP, DNS)

     • Network topologies (star, bus, mesh)

   • Later we'll discuss

     • Network security and threats

     • IP addressing and subnetting

     • Network troubleshooting techniques

   • Protocols and communication.

5. Security:

   • Basic principles of computer security: Computer security involves protecting computer systems and data from unauthorized access, use, disclosure, disruption, or destruction. It is based on several key principles, including:

     • Authentication and Authorization: Users must prove their identity (authentication) and be granted appropriate access privileges (authorization) to ensure that only authorized individuals can access sensitive information or perform specific actions.

     • Encryption: Encryption is the process of encoding data in a way that can only be decoded with the correct decryption key. It helps protect data during transmission and storage, making it unreadable to unauthorized parties.

     • Firewall: A firewall acts as a barrier between a private internal network and the public internet, monitoring and controlling network traffic based on predetermined security rules. It helps prevent unauthorized access to the network.

     • Regular Updates and Patches: Keeping software and systems up to date with the latest security updates and patches is crucial to address known vulnerabilities and protect against potential security breaches.

     • Backup and Recovery: Regularly backing up important data and having a comprehensive recovery plan in place can help mitigate the impact of data loss or system failures caused by security incidents or other events.

     Real life examples:

     • Locking your house and using a security system to protect it from unauthorized entry.

     • Keeping valuable belongings in a safe deposit box at a bank.

     Examples related to the topic:

     • Using a strong password and enabling two-factor authentication to secure your online accounts.

     • Installing antivirus software to protect your computer from malware and viruses.

     Want to know more? Google these points:

     • Types of cyber threats and attack vectors

     • Security best practices for online banking

     • Secure coding practices

     Later we'll discuss:

     • Intrusion detection systems

     • Network security protocols

     • Social engineering attacks

     • Authentication and authorization.