Operating Systems Lecture 2 PDF

Operating Systems Dr. Assem Khalaf Operating Systems  Lecture 2 3  File Management Overview Managing Files and Directories · File management is a critical function of the operating system that involves organizing and keeping track of files and directories on storage de...

Operating Systems Dr. Assem Khalaf Operating Systems  Lecture 2 3  File Management Overview Managing Files and Directories · File management is a critical function of the operating system that involves organizing and keeping track of files and directories on storage devices. · It allows users to create, store, retrieve, and manipulate files efficiently, providing a structured way to manage data. · The OS maintains a file system that keeps information about file names, types, locations, and access permissions, ensuring data integrity and security. 4  File Systems Different Types of File Systems (NTFS, FAT32, etc.) · A file system defines how data is stored and organized on a storage device. · Common file systems include: o NTFS (New Technology File System): Used ‫ش‬by Windows, supports large files, file permissions, and journaling for data recovery. o FAT32 (File Allocation Table 32): Older system compatible with many devices but limited to 4GB file sizes. o EXT4 (Fourth Extended File System): Commonly used in Linux, supports large volumes and files, efficient performance. · Each file system has its own advantages and limitations, influencing compatibility and performance. 5  File Operations File Creation, Deletion, Reading, and Writing · The OS handles various file operations essential for managing data: o File Creation: Allows users to create new files and define their attributes. o File Deletion: Enables users to remove files, freeing up storage space. o File Reading: Provides access to the contents of a file for viewing or processing. o File Writing: Saves data to a file, allowing for updates and modifications. · These operations are facilitated through system calls, ensuring that 6 users can interact with files seamlessly and securely.  Other OS Functions Overview Security, User Management, and Multitasking · Beyond basic functions, the OS also focuses on security, protecting data from unauthorized access. · User Management: Handles user accounts, permissions, and authentication, ensuring that each user has appropriate access rights. · Multitasking: Allows multiple processes to run concurrently, maximizing CPU usage and enhancing system performance. 7  User Interface Management Managing Graphical and Command-Line Interfaces · The OS provides user interfaces to facilitate interaction between users and the computer. · Graphical User Interface (GUI): Offers visual elements like windows, icons, and menus for intuitive navigation. · Command-Line Interface (CLI): Allows users to execute commands via text input, offering more control for advanced users. · The OS manages these interfaces to ensure smooth operation and user experience. 8  Resource Allocation Distributing System Resources Efficiently · Resource allocation is the process of distributing system resources, such as CPU time, memory, and storage, among various processes and users. · The OS prioritizes resource allocation based on process needs, user requirements, and system policies to ensure efficient performance and responsiveness. · Effective resource management prevents conflicts and optimizes the use of available hardware, contributing to overall system stability. 9  Overview of OS Services Brief Introduction to Key OS Services · Operating systems provide essential services that enable the execution of programs and manage hardware resources. · Key services include program execution, input/output operations, file system management, and communication between processes. · These services ensure that users and applications can interact with the computer efficiently and effectively, providing a foundation for all computing tasks. 10  Program Execution Overview How OS Starts and Stops Programs · The OS is responsible for launching applications and managing their execution. · When a program is started, the OS allocates necessary resources, such as memory and CPU time, and loads the program into memory. · Upon completion, the OS ensures proper termination by releasing resources and maintaining system stability. 11  Multitasking Running Multiple Programs Simultaneously · Multitasking allows users to run several applications at the same time, enhancing productivity and user experience. · The OS manages CPU time allocation between active processes, switching between them rapidly to give the illusion of simultaneous execution. · Effective multitasking ensures that resources are used efficiently and that applications remain responsive. 12  I/O Operation Overview How the OS Handles Input/Output Tasks · The OS manages input/output operations, facilitating communication between the computer and peripheral devices (like keyboards, mice, printers). · It provides an interface for applications to perform I/O tasks without needing to know the specifics of the hardware involved. · The OS ensures that data transfer between devices and memory is smooth and efficient, handling buffering, error checking, and scheduling. 13  Device Independence Importance of Abstracting Hardware Devices · Device independence means that applications can operate without needing to know the specifics of the underlying hardware. · The OS abstracts hardware details, providing a consistent interface for applications, allowing them to interact with different devices seamlessly. · This abstraction simplifies application development and enhances compatibility across various hardware configurations, ensuring that software can run on different systems without modification. 14  File System Overview How the OS Manages Files and Directories · The operating system (OS) organizes and manages files and directories on storage devices. · It provides a hierarchical structure, allowing users to create, modify, and delete files and folders easily. · The OS handles file metadata (such as size, type, and location) and ensures efficient storage and retrieval of data. 15  Permissions Setting File Access Permissions (Read/Write/Execute) · The OS enforces access controls to ensure that only authorized users can access or modify files. · Permissions can be set for different actions: reading (viewing), writing (modifying), and executing (running) files. · This security feature helps protect sensitive data and maintains system integrity by preventing unauthorized access. 16  Communication Overview Interprocess Communication (IPC) · Interprocess Communication (IPC) is a mechanism that allows processes to communicate and synchronize their actions. · The OS provides various IPC methods, such as pipes, message queues, and shared memory, enabling processes to exchange data and signals. · Effective IPC is crucial for multitasking environments where multiple processes need to work together seamlessly. 17  Networking How OS Supports Network Communication · The OS manages network connections, enabling computers to communicate over local and wide area networks. · It provides protocols for data transmission, error checking, and ensuring reliable communication between devices. · The OS also handles socket programming, allowing applications to send and receive data over the network easily. 18  Error Handling Overview Managing and Recovering from Errors · The OS is responsible for detecting, reporting, and recovering from errors that occur during operation. · It maintains logs of errors and provides mechanisms for diagnosing issues, allowing users and administrators to troubleshoot effectively. · Error handling ensures system stability and minimizes downtime, maintaining the overall reliability of the operating system. 19  Types of Errors Different Types of Errors: Hardware, Software, etc. · Errors can be categorized into various types, including hardware errors (e.g., disk failures, memory errors) and software errors (e.g., application crashes, bugs). · Understanding the types of errors helps in diagnosing problems and implementing appropriate fixes or preventive measures. · The OS employs strategies to isolate and recover from errors, minimizing their impact on overall system performance and user experience. 20  Resource Management Overview Allocating CPU, Memory, and Devices to Programs · The operating system (OS) efficiently allocates system resources such as CPU time, memory, and hardware devices to running programs. · It ensures that resources are distributed fairly and optimally to avoid conflicts and ensure smooth performance. · The OS also handles resource prioritization, giving critical programs more access to necessary resources. 21  Deadlock Prevention Techniques for Avoiding Deadlocks · A deadlock occurs when two or more programs are stuck waiting for each other to release resources, leading to a system halt. · The OS employs strategies like resource allocation ordering and timeout mechanisms to prevent deadlocks. · Deadlock prevention ensures system stability by avoiding resource conflicts that could disrupt program execution. 22  Protection Overview Ensuring System Security and Integrity · The OS protects system resources from unauthorized access or malicious activities. · It enforces security policies, monitors activity, and restricts access to sensitive data and resources. · Protection mechanisms are crucial for maintaining the integrity of the system and preventing data breaches or system corruption. 23 Thank you Dr. Assem Khalaf