A presentation on the Ext4 file system and the evolution of Ext filesystem in Linux operating system. Linux uses virtual filesystem. The comparison of the ext filesystem generations is provided.
Course 102: Lecture 26: FileSystems in Linux (Part 1) Ahmed El-Arabawy
This lecture introduces some concepts about FileSystems in Linux.
Video for this lecture on youtube:
http://www.youtube.com/watch?v=9jj1QOokACo
Check the other Lectures and courses in
http://Linux4EnbeddedSystems.com
or Follow our Facebook Group at
- Facebook: @LinuxforEmbeddedSystems
Lecturer Profile:
Ahmed ElArabawy
- https://www.linkedin.com/in/ahmedelarabawy
The document discusses Linux file systems. It provides an overview of Linux file system types including network file systems like NFS and SMB, and disk file systems like ext2, ext3, FAT32, and NTFS. It describes the physical structure of file systems on disk including the boot block, super block, inode list, and block list. It also summarizes the features and maximum sizes of different file system standards like ext2, ext3, ext4, ReiserFS, XFS, and JFS.
This ppt discusses the history of both the operating systems & compares both of them in terms of Kernel, memory management, GUI and application support.
The document provides an overview of file systems, including their purpose of organizing and storing information on storage devices. It discusses key aspects of file systems such as how they separate information into individual files and directories, use metadata to store attributes about files, allocate storage space in a granular manner (which can result in unused space), become fragmented over time, and use various utilities and structures to implement these functions while maintaining integrity of data and restricting access. File systems are a critical component of operating systems that allow for efficient organization, retrieval and updating of user data on different types of storage media and devices.
Disk and File System Management in LinuxHenry Osborne
This document discusses disk and file system management in Linux. It covers MBR and GPT partition schemes, logical volume management, common file systems like ext4 and XFS, mounting file systems, and file system maintenance tools. It also discusses disk quotas, file ownership, permissions, and the umask command for setting default permissions.
The document discusses various topics related to Linux administration. It covers Unix system architecture, the Linux command line, files and directories, running programs, wildcards, text editors, shells, command syntax, filenames, command history, paths, hidden files, home directories, making directories, copying and renaming files, and more. It provides an overview of key Linux concepts and commands for system administration.
The document summarizes how to write a character device driver in Linux. It covers the anatomy of a device driver including the user interface via device files, and kernel interfaces via file operations and major/minor numbers. It describes registering a character driver by defining file operations, reserving major/minor numbers, and associating them. Open and release functions handle initialization and cleanup. Read/write functions transfer data between userspace and hardware. Ioctl allows extending functionality.
The document discusses the NTFS file system. It describes the key components of NTFS including the master file table (MFT), MFT records, attributes, and how data is allocated and structured on disk. It provides details on how files are added, deleted and recovered from NTFS. It also discusses tools that can be used to analyze and examine NTFS file systems like icat, istat and fsstat.
Course 102: Lecture 26: FileSystems in Linux (Part 1) Ahmed El-Arabawy
This lecture introduces some concepts about FileSystems in Linux.
Video for this lecture on youtube:
http://www.youtube.com/watch?v=9jj1QOokACo
Check the other Lectures and courses in
http://Linux4EnbeddedSystems.com
or Follow our Facebook Group at
- Facebook: @LinuxforEmbeddedSystems
Lecturer Profile:
Ahmed ElArabawy
- https://www.linkedin.com/in/ahmedelarabawy
The document discusses Linux file systems. It provides an overview of Linux file system types including network file systems like NFS and SMB, and disk file systems like ext2, ext3, FAT32, and NTFS. It describes the physical structure of file systems on disk including the boot block, super block, inode list, and block list. It also summarizes the features and maximum sizes of different file system standards like ext2, ext3, ext4, ReiserFS, XFS, and JFS.
This ppt discusses the history of both the operating systems & compares both of them in terms of Kernel, memory management, GUI and application support.
The document provides an overview of file systems, including their purpose of organizing and storing information on storage devices. It discusses key aspects of file systems such as how they separate information into individual files and directories, use metadata to store attributes about files, allocate storage space in a granular manner (which can result in unused space), become fragmented over time, and use various utilities and structures to implement these functions while maintaining integrity of data and restricting access. File systems are a critical component of operating systems that allow for efficient organization, retrieval and updating of user data on different types of storage media and devices.
Disk and File System Management in LinuxHenry Osborne
This document discusses disk and file system management in Linux. It covers MBR and GPT partition schemes, logical volume management, common file systems like ext4 and XFS, mounting file systems, and file system maintenance tools. It also discusses disk quotas, file ownership, permissions, and the umask command for setting default permissions.
The document discusses various topics related to Linux administration. It covers Unix system architecture, the Linux command line, files and directories, running programs, wildcards, text editors, shells, command syntax, filenames, command history, paths, hidden files, home directories, making directories, copying and renaming files, and more. It provides an overview of key Linux concepts and commands for system administration.
The document summarizes how to write a character device driver in Linux. It covers the anatomy of a device driver including the user interface via device files, and kernel interfaces via file operations and major/minor numbers. It describes registering a character driver by defining file operations, reserving major/minor numbers, and associating them. Open and release functions handle initialization and cleanup. Read/write functions transfer data between userspace and hardware. Ioctl allows extending functionality.
The document discusses the NTFS file system. It describes the key components of NTFS including the master file table (MFT), MFT records, attributes, and how data is allocated and structured on disk. It provides details on how files are added, deleted and recovered from NTFS. It also discusses tools that can be used to analyze and examine NTFS file systems like icat, istat and fsstat.
The document describes the Linux file system hierarchy. It explains that the root of the hierarchy is / and then describes the purpose and contents of important directories like /bin, /boot, /dev, /etc, /home, /media, /mnt, /opt, /proc, /root, /sbin, /tmp, /usr, and /var. For example, it states that /bin contains common commands, /dev contains device files, and /home contains user directories.
NTFS is a file system introduced by Microsoft in 1993 for Windows NT operating systems. It improved on previous file systems with features like larger storage capacity support, redundancy, security, and performance improvements important for businesses. NTFS formats volumes with system files including the Master File Table that stores metadata for all files and folders. It provides security, compression, encryption and other advanced features through file attributes. NTFS also supports features like sparse files, recoverability, and alternate data streams.
The document discusses memory segmentation and paging techniques used in operating systems. Segmentation divides memory into variable-length segments, while paging divides memory into fixed-size pages. Paging maps logical pages to physical frame addresses using a page table for efficient memory access. It allows programs to access more memory than is physically available by swapping pages between memory and disk. The combination of segmentation and paging provides memory protection and reduces internal and external fragmentation.
The document discusses file systems and their components. It describes how files are organized logically and mapped to physical storage. It covers key file system concepts like directories, file allocation schemes, file attributes, and file operations. It also summarizes common file systems like FAT, FAT32, and NTFS and compares their features such as supported drive sizes, cluster sizes, and compatibility with different operating systems.
The document discusses the architecture of the Linux operating system. It contains five main components: the kernel, system libraries, hardware layer, system utilities, and shell. The kernel is the core of the operating system that facilitates interactions between hardware and software. It connects applications to system hardware. The system libraries help applications access the kernel's features through system calls. System utilities provide specialized functions to users. The hardware layer refers to physical machine components like RAM and CPU. The shell acts as an interface between the kernel and user, running kernel functions and taking user commands.
Disk management / hard drive partition management / create drive or partition...Ajay Panchal
This is a ppt presentation that provide you to information about the hard drive partitions, it also provide a knowledge about the hard drive and multiple hard drive in a single computer.
- Shell scripting allows users to automate repetitive tasks by writing scripts of shell commands that can be executed automatically. The shell acts as an interface between the user and the operating system kernel, accepting commands and passing them to the kernel for execution. Common shells used for scripting include Bash, C Shell, and Korn Shell. Shell scripts use shell commands, control structures, and functions to perform automated tasks like backups and system monitoring.
Linux uses a unified, hierarchical file system to organize and store data on disk partitions. It places all partitions under the root directory by mounting them at specific points. The file system is case sensitive. The Linux kernel manages hardware resources and the file system, while users interact through commands interpreted by the shell. Journaling file systems like ext3 and ReiserFS were developed to improve robustness over ext2 by logging file system changes to reduce the need for integrity checks after crashes. Ext4 further improved on this with features like larger maximum file sizes and delayed allocation.
This document discusses resource monitoring and management processes and disks in Linux systems. It covers:
- Monitoring processes using tools like ps and top to view process states, CPU usage, and memory usage. Processes can be prioritized using nice or renice.
- Signals can be used for inter-process communication and process control via signals sent using kill.
- Disks can be partitioned and formatted with filesystems like ext4. Logical volumes using LVM provide more flexibility in storage allocation.
- Periodic tasks like backups and log rotations can be automated using cron jobs run on schedules.
- File management involves organizing files in a hierarchical structure using directories, folders, and paths to track file locations.
- The operating system provides tools like File Explorer to manage files by renaming, copying, moving, and deleting them. Files are organized into folders and drives to improve organization.
- Key file attributes include the file name, extension, size, date created/modified, and format which is indicated by the extension and determines what application can open the file.
Operating system 24 mutex locks and semaphoresVaibhav Khanna
Mutual Exclusion - If process Pi is executing in its critical section, then no other processes can be executing in their critical sections
2. Progress - If no process is executing in its critical section and there exist some processes that wish to enter their critical section, then the selection of the processes that will enter the critical section next cannot be postponed indefinitely
3. Bounded Waiting - A bound must exist on the number of times that other processes are allowed to enter their critical sections after a process has made a request to enter its critical section and before that request is granted
Assume that each process executes at a nonzero speed
No assumption concerning relative speed of the n processes
The document discusses Windows XP's scheduling algorithm. It uses a priority-based, preemptive approach with 32 priority levels divided into variable and real-time classes. The scheduler ensures the highest priority thread runs by maintaining queues for each priority level and traversing from highest to lowest. Threads start at the process' base priority and may have their priority lowered after time quantums expire to limit CPU consumption of compute-intensive threads.
The document discusses different aspects of file systems and file structures. It describes files as collections of data that have long-term existence, can be shared between processes, and organized hierarchically. File systems provide storage for files and functions to manipulate them, maintaining attributes. Common file structures include sequential, indexed sequential, and direct/hashed files. The document also outlines the components of a file system software architecture and operations performed on directories.
The document discusses input/output (I/O) and file management in operating systems. It covers several key topics:
1) I/O devices are controlled by the OS and include input devices like keyboards and output devices like monitors. Files are managed through a logical, uniform view abstracted from physical storage properties.
2) A file is a collection of related information defined by its creator, such as programs, data, text, or formatted records. File management involves creation, deletion, mapping to storage, and backup.
3) The OS implements I/O buffering and caching to improve performance and address speed mismatches between devices. It also performs disk scheduling and structures file storage through directories, indexing,
Memory management is the act of managing computer memory. The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to programs at their request, and free it for reuse when no longer needed. This is critical to any advanced computer system where more than a single process might be underway at any time
This document discusses Linux file permissions. It explains that Linux is a multi-user and multi-tasking system, so permissions can be set for files and directories using the chmod command. The chmod command allows changing permissions for the file owner, group owners, and other users using either symbolic modes like u+rwx or octal notation. It also covers the chown and chgrp commands for changing file ownership and group.
This document discusses different approaches to memory management in computer systems. It explains that memory plays a central role, with the CPU and I/O system interacting with memory. It then describes four approaches to memory allocation and management: contiguous storage allocation, non-contiguous storage allocation, virtual storage using paging, and virtual storage using segmentation. Paging divides memory into fixed-size frames and logical memory into same-sized pages, using a page table to map logical to physical addresses. Segmentation divides a program into variable-sized segments and uses a segment table to map two-dimensional physical addresses. The most efficient approach sometimes combines paging and segmentation.
The document discusses Linux file systems. It describes that Linux uses a hierarchical tree structure with everything treated as a file. It explains the basic components of a file system including the boot block, super block, inode list, and block list. It then covers different types of file systems for Linux like ext2, ext3, ext4, FAT32, NTFS, and network file systems like NFS and SMB. It also discusses absolute vs relative paths and mounting and unmounting filesystems using the mount and umount commands.
The document discusses two Linux file systems: ext4 and BTRFS. Ext4 is the latest version of the ext file system family and aims to overcome limitations of ext3, such as larger file and volume sizes and improved performance. BTRFS is a newer file system that uses B-trees for its structures and aims to replace ext3/4 with new storage management approaches like snapshots and copy-on-write. The document provides details on the technical specifications and features of each file system.
Course 102: Lecture 27: FileSystems in Linux (Part 2)Ahmed El-Arabawy
This lecture goes through the different types of Filesystems and some commands that are used with filesystems. It introduces the filesystems ext2/3/4 , JFFS2, cramfs, ramfs, tmpfs, and NFS.
Video for this lecture on youtube:
http://www.youtube.com/watch?v=XPtPsc6uaKY
Check the other Lectures and courses in
http://Linux4EnbeddedSystems.com
or Follow our Facebook Group at
- Facebook: @LinuxforEmbeddedSystems
Lecturer Profile:
Ahmed ElArabawy
- https://www.linkedin.com/in/ahmedelarabawy
The document describes the Linux file system hierarchy. It explains that the root of the hierarchy is / and then describes the purpose and contents of important directories like /bin, /boot, /dev, /etc, /home, /media, /mnt, /opt, /proc, /root, /sbin, /tmp, /usr, and /var. For example, it states that /bin contains common commands, /dev contains device files, and /home contains user directories.
NTFS is a file system introduced by Microsoft in 1993 for Windows NT operating systems. It improved on previous file systems with features like larger storage capacity support, redundancy, security, and performance improvements important for businesses. NTFS formats volumes with system files including the Master File Table that stores metadata for all files and folders. It provides security, compression, encryption and other advanced features through file attributes. NTFS also supports features like sparse files, recoverability, and alternate data streams.
The document discusses memory segmentation and paging techniques used in operating systems. Segmentation divides memory into variable-length segments, while paging divides memory into fixed-size pages. Paging maps logical pages to physical frame addresses using a page table for efficient memory access. It allows programs to access more memory than is physically available by swapping pages between memory and disk. The combination of segmentation and paging provides memory protection and reduces internal and external fragmentation.
The document discusses file systems and their components. It describes how files are organized logically and mapped to physical storage. It covers key file system concepts like directories, file allocation schemes, file attributes, and file operations. It also summarizes common file systems like FAT, FAT32, and NTFS and compares their features such as supported drive sizes, cluster sizes, and compatibility with different operating systems.
The document discusses the architecture of the Linux operating system. It contains five main components: the kernel, system libraries, hardware layer, system utilities, and shell. The kernel is the core of the operating system that facilitates interactions between hardware and software. It connects applications to system hardware. The system libraries help applications access the kernel's features through system calls. System utilities provide specialized functions to users. The hardware layer refers to physical machine components like RAM and CPU. The shell acts as an interface between the kernel and user, running kernel functions and taking user commands.
Disk management / hard drive partition management / create drive or partition...Ajay Panchal
This is a ppt presentation that provide you to information about the hard drive partitions, it also provide a knowledge about the hard drive and multiple hard drive in a single computer.
- Shell scripting allows users to automate repetitive tasks by writing scripts of shell commands that can be executed automatically. The shell acts as an interface between the user and the operating system kernel, accepting commands and passing them to the kernel for execution. Common shells used for scripting include Bash, C Shell, and Korn Shell. Shell scripts use shell commands, control structures, and functions to perform automated tasks like backups and system monitoring.
Linux uses a unified, hierarchical file system to organize and store data on disk partitions. It places all partitions under the root directory by mounting them at specific points. The file system is case sensitive. The Linux kernel manages hardware resources and the file system, while users interact through commands interpreted by the shell. Journaling file systems like ext3 and ReiserFS were developed to improve robustness over ext2 by logging file system changes to reduce the need for integrity checks after crashes. Ext4 further improved on this with features like larger maximum file sizes and delayed allocation.
This document discusses resource monitoring and management processes and disks in Linux systems. It covers:
- Monitoring processes using tools like ps and top to view process states, CPU usage, and memory usage. Processes can be prioritized using nice or renice.
- Signals can be used for inter-process communication and process control via signals sent using kill.
- Disks can be partitioned and formatted with filesystems like ext4. Logical volumes using LVM provide more flexibility in storage allocation.
- Periodic tasks like backups and log rotations can be automated using cron jobs run on schedules.
- File management involves organizing files in a hierarchical structure using directories, folders, and paths to track file locations.
- The operating system provides tools like File Explorer to manage files by renaming, copying, moving, and deleting them. Files are organized into folders and drives to improve organization.
- Key file attributes include the file name, extension, size, date created/modified, and format which is indicated by the extension and determines what application can open the file.
Operating system 24 mutex locks and semaphoresVaibhav Khanna
Mutual Exclusion - If process Pi is executing in its critical section, then no other processes can be executing in their critical sections
2. Progress - If no process is executing in its critical section and there exist some processes that wish to enter their critical section, then the selection of the processes that will enter the critical section next cannot be postponed indefinitely
3. Bounded Waiting - A bound must exist on the number of times that other processes are allowed to enter their critical sections after a process has made a request to enter its critical section and before that request is granted
Assume that each process executes at a nonzero speed
No assumption concerning relative speed of the n processes
The document discusses Windows XP's scheduling algorithm. It uses a priority-based, preemptive approach with 32 priority levels divided into variable and real-time classes. The scheduler ensures the highest priority thread runs by maintaining queues for each priority level and traversing from highest to lowest. Threads start at the process' base priority and may have their priority lowered after time quantums expire to limit CPU consumption of compute-intensive threads.
The document discusses different aspects of file systems and file structures. It describes files as collections of data that have long-term existence, can be shared between processes, and organized hierarchically. File systems provide storage for files and functions to manipulate them, maintaining attributes. Common file structures include sequential, indexed sequential, and direct/hashed files. The document also outlines the components of a file system software architecture and operations performed on directories.
The document discusses input/output (I/O) and file management in operating systems. It covers several key topics:
1) I/O devices are controlled by the OS and include input devices like keyboards and output devices like monitors. Files are managed through a logical, uniform view abstracted from physical storage properties.
2) A file is a collection of related information defined by its creator, such as programs, data, text, or formatted records. File management involves creation, deletion, mapping to storage, and backup.
3) The OS implements I/O buffering and caching to improve performance and address speed mismatches between devices. It also performs disk scheduling and structures file storage through directories, indexing,
Memory management is the act of managing computer memory. The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to programs at their request, and free it for reuse when no longer needed. This is critical to any advanced computer system where more than a single process might be underway at any time
This document discusses Linux file permissions. It explains that Linux is a multi-user and multi-tasking system, so permissions can be set for files and directories using the chmod command. The chmod command allows changing permissions for the file owner, group owners, and other users using either symbolic modes like u+rwx or octal notation. It also covers the chown and chgrp commands for changing file ownership and group.
This document discusses different approaches to memory management in computer systems. It explains that memory plays a central role, with the CPU and I/O system interacting with memory. It then describes four approaches to memory allocation and management: contiguous storage allocation, non-contiguous storage allocation, virtual storage using paging, and virtual storage using segmentation. Paging divides memory into fixed-size frames and logical memory into same-sized pages, using a page table to map logical to physical addresses. Segmentation divides a program into variable-sized segments and uses a segment table to map two-dimensional physical addresses. The most efficient approach sometimes combines paging and segmentation.
The document discusses Linux file systems. It describes that Linux uses a hierarchical tree structure with everything treated as a file. It explains the basic components of a file system including the boot block, super block, inode list, and block list. It then covers different types of file systems for Linux like ext2, ext3, ext4, FAT32, NTFS, and network file systems like NFS and SMB. It also discusses absolute vs relative paths and mounting and unmounting filesystems using the mount and umount commands.
The document discusses two Linux file systems: ext4 and BTRFS. Ext4 is the latest version of the ext file system family and aims to overcome limitations of ext3, such as larger file and volume sizes and improved performance. BTRFS is a newer file system that uses B-trees for its structures and aims to replace ext3/4 with new storage management approaches like snapshots and copy-on-write. The document provides details on the technical specifications and features of each file system.
Course 102: Lecture 27: FileSystems in Linux (Part 2)Ahmed El-Arabawy
This lecture goes through the different types of Filesystems and some commands that are used with filesystems. It introduces the filesystems ext2/3/4 , JFFS2, cramfs, ramfs, tmpfs, and NFS.
Video for this lecture on youtube:
http://www.youtube.com/watch?v=XPtPsc6uaKY
Check the other Lectures and courses in
http://Linux4EnbeddedSystems.com
or Follow our Facebook Group at
- Facebook: @LinuxforEmbeddedSystems
Lecturer Profile:
Ahmed ElArabawy
- https://www.linkedin.com/in/ahmedelarabawy
Poking The Filesystem For Fun And Profitssusera432ea1
1) The document discusses writing a rogue filesystem driver that could be used as an attacker tool. It covers motivation, filesystem internals, types of filesystem drivers, and how to write a rogue filesystem driver by implementing functions like superblock operations, inode operations, and file operations.
2) A rogue filesystem driver could be difficult to detect and could selectively spoof, block, or hide file contents to gain a strong foothold in the system. It does not require hooking system calls or compromising the kernel in the same way.
3) Key aspects of developing a rogue driver involve registering the filesystem type, setting up superblock operations, and implementing inode, directory, and file operations to handle
It is the File system that is contained on the same partition on which the "Root directory" is located. It is the File system on which all the other file systems are mounted
This document summarizes key concepts related to I/O structure in operating systems, including disk structure, disk scheduling, disk management, and swap-space management. It discusses how disks are logically addressed and mapped to physical sectors. It also describes different disk scheduling algorithms like SSTF, SCAN, C-SCAN and factors that influence algorithm selection. The document outlines the processes involved in low-level formatting, logical formatting, and handling bad blocks. It concludes with an overview of swap-space management in various operating systems.
This document provides an overview of Windows file systems and how they are used for digital forensics investigations. It discusses the File Allocation Table (FAT) file system and how it tracks file clusters. It also describes the New Technology File System (NTFS) and how it stores file metadata and tracks unused data clusters. The document outlines how file deletion, renaming and moving works in Windows, and artifacts that can be recovered from deleted files. It identifies several useful file types for forensic analysis, like shortcut files, the Recycle Bin, print spool files and registry keys.
OSDC 2011 | Enterprise Linux Server Filesystems by Remo RickliNETWAYS
Der Einsatz des richtigen Filesystems ist noch immer eine grundlegende Entscheidung mit großem Einfluss auf spätere Performance und Management. Mit Ext4 und BTRFS gibt es nun zwei neue Alternativen die der Erwartungshaltung bisherige Schwachstellen auszumerzen standhalten müssen. Während Ext4 bereits stable ist und den Sprung in die gängigen Enterprise Distributionen geschafft hat, steht das von Oracle BTRFS hier noch eher am Anfang. Trotz des scheinbaren Nachteils sehen vielen in BTRFS das nächste Standardfilesystem für Linux, da es im Vergleich bestehenden Limitierungen von Ext4 auflöst und als die Linux-Alternative zu ZFS gesehen wird.
Der Vortrag erläutert Architektur und Charakteristiken beider Dateisysteme, bewertet sie aus Sicht eines Systemadministrators für den Einsatz im Rechenzentrum und beschreibt mögliche Migrationspfade.
The document discusses file management in operating systems. It covers topics such as the basic functions of a file system, different file organization techniques like sequential, direct and indexed sequential, file structures, file allocation methods like contiguous, linked and indexed, free space management using free lists or bitmaps, file access control, and backup techniques. File systems are responsible for organizing files and managing access to data on storage devices in a way that facilitates navigation and protects data from corruption or loss.
This document summarizes key concepts about file systems in Linux:
1. It describes the structure of file systems including superblocks, inodes, and data blocks. Inodes contain metadata about files and pointers to data blocks.
2. It discusses device files that correspond to devices in the system and are represented in the /dev directory. Each device has a major and minor ID.
3. Journaling file systems like ext4 are described which eliminate the need for lengthy consistency checks after crashes by journaling file system updates.
4. The concept of mounting other file systems at mount points under the single directory hierarchy rooted at / is summarized along with the mount() and umount() system calls.
The Btrfs filesystem was jointly developed by several companies including Oracle and Redhat. It uses copy-on-write and maintains CRCs for metadata and data. Features include snapshots, multi-device support, online resizing and compression. Performance and stability have improved through fixes and new tools allow automated repair of corrupt blocks. Storage is allocated through extent and chunk trees which map logical to physical blocks and allow different RAID levels for data and metadata. Btrfs works well with flash storage through trim support and hints to optimize device lifetime and performance.
The Virtual File System (VFS) provides a standardized interface for user programs to access different types of file systems. It uses various data structures like superblocks, inodes, dentries, and files to represent file system objects and metadata. System calls allow programs to interact with the operating system kernel to perform operations on these VFS objects. The VFS implements various caching mechanisms like the dentry cache to improve performance. It also supports features like namespaces and mounting/unmounting of different file systems.
The document discusses several aspects of file and directory structure in operating systems. It describes different approaches to implementing directories, including linear lists and hash tables. It also discusses file access mechanisms in distributed file systems, including how file name mapping, caching, and various protocols for open, read, and close operations work. The key components of a file system structure, such as the logical file system, file organization module, and layers of an application program, logical file system, and file organization are also summarized.
The document discusses file systems and different types of file systems. It provides information on what a file and file system is, the main components of a file system including directories and file allocation methods. It also summarizes the key differences between common file systems like FAT32, NTFS, and exFAT and describes their ideal usage cases. Different structures for organizing files in directories like single-level, two-level, and tree-structured directories are also covered along with the advantages of maintaining directories.
The document discusses file systems in Windows. It describes the FAT and NTFS file systems used in Windows. FAT stores file information in a file allocation table and uses a linked list data structure. NTFS stores file data and metadata in a master file table. Key differences are that NTFS supports larger storage, permissions, and compression while FAT32 is more compatible across platforms but less secure locally.
AOS Lab 9: File system -- Of buffers, logs, and blocksZubair Nabi
The document describes the file system layers in xv6, including the buffer cache, logging, and on-disk layout. The buffer cache synchronizes access to disk blocks and caches popular blocks in memory. The logging layer ensures atomicity by wrapping file system updates in transactions written to a log on disk before writing to the file system structures. The on-disk layout divides the disk into sections for the boot sector, superblock, inodes, bitmap, data blocks, and log blocks.
Do journaling filesystems guarantee against corruption after a power failure (1)Rudhramoorthi Andiappan
Journaling file systems record file system changes in a journal before committing them to the main file system. This allows the file system to be brought back online more quickly after a crash with lower likelihood of corruption. Different journaling modes trade off performance versus data integrity - writeback journals metadata only for best performance but risks data corruption, while data mode journals all changes for maximum integrity but lower performance. Common Linux journaling file systems include Ext3, XFS, JFS, and ReiserFS, each using different journaling strategies and optimizations.
The document discusses Linux file systems and input/output. It describes the basic structure of Linux file systems, including the root directory and common file system types like Ext4, XFS, and Btrfs. It also summarizes the different classes of devices in Linux - block devices, character devices, and network devices. Block devices provide access to storage and allow random access to fixed sized blocks. Character devices process data sequentially and include keyboards and printers. Network devices operate indirectly through sockets, protocols, and network drivers.
The document discusses various aspects of file system implementation in operating systems. It covers file system structure, layers, and in-memory structures. It describes different directory implementation methods like linear lists and hash tables. For allocation methods, it explains contiguous, extent-based, linked, and indexed allocation. It also covers free space management using bitmaps and linked lists. Performance tradeoffs of different allocation methods are discussed.
This document summarizes a lecture on file system implementation. It discusses:
- File system structure including logical file system, file organization module, basic file system, and device drivers.
- Key data structures including file control blocks, mount table, directory cache, open file tables.
- Allocation methods like contiguous, linked, and indexed allocation.
- Free space management techniques like bit vectors, linked lists, and grouping.
- Caching strategies to improve performance like disk caching, read-ahead, and memory mapping.
The document discusses Linux file systems and partitioning. It describes how to use the fdisk command to view and create partitions, and supported local file systems like Ext2, Ext3, Vfat, and ISO9660. It provides details on Ext3 file system structure, creation, conversion from Ext2, and tools like dumpe2fs, fsck, and tune2fs. It also covers mounting file systems using mount, automatic mounting from /etc/fstab, and unmounting file systems with umount.
Unlocking Productivity: Leveraging the Potential of Copilot in Microsoft 365, a presentation by Christoforos Vlachos, Senior Solutions Manager – Modern Workplace, Uni Systems
Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...SOFTTECHHUB
The choice of an operating system plays a pivotal role in shaping our computing experience. For decades, Microsoft's Windows has dominated the market, offering a familiar and widely adopted platform for personal and professional use. However, as technological advancements continue to push the boundaries of innovation, alternative operating systems have emerged, challenging the status quo and offering users a fresh perspective on computing.
One such alternative that has garnered significant attention and acclaim is Nitrux Linux 3.5.0, a sleek, powerful, and user-friendly Linux distribution that promises to redefine the way we interact with our devices. With its focus on performance, security, and customization, Nitrux Linux presents a compelling case for those seeking to break free from the constraints of proprietary software and embrace the freedom and flexibility of open-source computing.
Best 20 SEO Techniques To Improve Website Visibility In SERPPixlogix Infotech
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Ext filesystem4
1. The ext filesystem
A four generation retrospective
Presented by –
Neha Kulkarni (5202)
ME Computer
Pune Institute of Computer Technology
2. Outline
• Linux file system
• Virtual file system
• Ext file system
• Ext2 file system
• Ext3 file system
• Ext4 file system
• Comparison
• Conclusion
• References
3. Linux filesystem
• A file system is an abstraction that supports the
creation, deletion, and modification of files, and
organization of files into directories.
• Linux uses the File System Hierarchy (FSH)
standard.
• Modern UNIX systems allow disks to be
partitioned into two or more separate physical
entities, each containing a distinct file system.
• Modern UNIX file systems are virtual file systems,
designed to handle many different types of
underlying physical file systems.
4. In the FHS, all files and directories appear under the
root directory /, even if they are stored on different
physical or virtual devices
5.
6. • The superblock contains all of the information
about how the file system is configured, such
as block size, block address range, and mount
status.
• The i-nodes contain the file attributes and a
map indicating where the blocks of the file are
located on the disk. They are of 128 bytes.
• The data blocks are where file contents are
stored.
• i-node in position 2 of the table usually points
to the entry for the root directory file in the
file system.
9. ext filesystem
• Implemented in April 1992 as the first file system
specifically for the Linux kernel
• It was the first implementation that used the
virtual file system, for which support was added
in the Linux kernel in version 0.96c, and it could
handle file systems up to 2GB in size.
• Filenames were allowed up to 255 characters.
• Only one timestamp, no data modification
timestamps
• Use of linked-list for free space- caused
fragmentation
11. ext2 filesystem
• Designed by Remy Card in January 1993
• Designed and implemented to fix some problems
present in the first extended file system.
• Maximal file size 2GB, can be extended up to 4TB
• Provides long file names up to 255 characters
• Reserves around 5% of the blocks for super-user
• User can set attributes on files or directories
• Allows the administrator to choose the logical
block size when creating the file system (1024B,
2048B, 4096B)
12. • Implements fast symbolic links (upto 60
characters)
• Keeps track of the file system state
• Immutable files can only be read. Nobody can
write or delete them.
• Directories are managed as linked lists of
variable length entries
• Data modification timestamps were available
• ext2 partitions can be converted to ext3 and vice-
versa without any need for backing up the data
and repartitioning
15. • The superblock is defined in struct ext2_super_block, line 339
of include/linux/ext2_fs.h
• A group descriptor is defined by ext2_group_descr structure,
line 148 of ext2_fs.h
• Block number of the first block of inode table is stored in the
bg_inode_table field of the group descriptor.
• i_mode determines the type and access rights of a file. They
are present in sys/stat.h
16. Directory inode
Directory entries in the inode table require special attention. To test if an inode refers
to a directory file we can use the S_ISDIR(mode) macro:
if (S_ISDIR(inode.i_mode))
In the case of directory entries, the data blocks pointed by i_block[] contain a list of
the files in the directory and their respective inode numbers.
17. Locating a file
int fd = open("/home/ealtieri/hello.txt", O_RDONLY);
The desired file is hello.txt, while its path is /home/ealtieri/hello.txt.
Once the inode of the file is known, the data blocks belonging to the hello.txt are specified
by the inode.block[] array.
18. ext3 filesystem
• ext3, or third extended filesystem, is a
journalled filesystem.
• The filesystem was merged with the mainline
Linux kernel in November 2001 from 2.4.15
onward.
• Its main advantage over ext2 is journaling,
which improves reliability and eliminates the
need to check the file system after an unclean
shutdown.
19. • ext3 adds the following features to ext2:
- A journal
- Online file system growth
- HTree indexing for larger directories – 32
bit
• Maximum file size is 16GB-2TB
• Maximum file system size is 2TB-32TB
• The max number of blocks for ext3 is 232
20. • Journalling levels:
– Journal (Lowest risk) -
Both metadata and file contents are written to the
journal before being committed to the main file
system.
– Ordered (medium risk) -
Only metadata is journalled, file contents are written
to the disk before associated metadata is marked as
committed in the journal.
– Writeback (highest risk) -
Only metadata is journalled, file contents are not.
Contents might be written before or after the journal
I is updated.
21. Block allocator
• When allocating a block for a file, the Ext3 block
allocator always starts from the block group
where the i-node structure is stored to keep the
meta-data and data blocks close to each other
• In case of multiple files allocating blocks
concurrently, the Ext3 block allocator uses block
reservation to make sure that subsequent
requests for blocks for a particular file get served
before it is interleaved with other files.
• Ext3 still uses the bitmap to search for the free
blocks to reserve
22. Disadvantages of ext3
• Ext3 lacks recent features such as extents, dynamic
allocation of inodes, block sub-allocation.
• A directory can have at the most 31998 subdirectories.
• No online defragmentation tool
• Does not support the recovery of deleted files
• Does not have native support for snapshots
• No check-summing while writing the journal
• Ext3 stores dates as Unix time using four bytes in the
file header. 32 bits does not give enough scope to
continue processing files beyond January 18, 2038.
23. ext4 filesystem
• It supports 48-bit block addressing, so it will
have 1 EB of maximum filesystem size and 16
TB of maximum file size.
• 1 EB = 1,048,576 TB (1 EB = 1024 PB, 1 PB =
1024 TB, 1 TB = 1024 GB)
• Ext4 allows an unlimited number of sub
directories
24. Extents
• Extent mapping is used in Ext4 to represent new files, rather
than the double, triple indirect block mapping used in Ext2/3.
25. Ext4 block allocator
• Main goal is to provide better allocation for
small and large files
• Ext4 uses a "multiblock allocator" (mballoc).
• Persistent pre-allocation :
Applications tell the filesystem to preallocate
the space.
• The feature is available via the
libc posix_fallocate() interface
26. Delayed Allocation
• Delayed allocation defers block allocations from
write() operation time to page flush time.
• It increases the opportunity to combine many
block allocation requests into a single request
reducing fragmentation
• Saves CPU cycles, and avoids unnecessary block
allocation for short-lived files
• The current Ext4 delayed allocation only supports
data=writeback journalling mode.
27. Inode features
• Larger inodes: Ext4 will default to 256 bytes. This is needed
to accommodate some extra fields (like nanosecond
timestamps or inode versioning), and the remaining space
of the inode will be used to store extend attributes that are
small enough to fit it that space. This will make the access
to those attributes much faster, and improves the
performance of applications that use extend attributes by a
factor of 3-7 times.
• Inode reservation consists in reserving several inodes when
a directory is created, expecting that they will be used in
the future.
• Nanoseconds timestamps means that inode fields like
"modified time" will be able to use nanosecond resolution
instead of the second resolution of Ext3.
28. Journalling
• Ext4 checksums the journal data to know if
the journal blocks are failing or corrupted.
• In Ext4 the journaling feature can be disabled,
which provides a small performance
improvement.
29. Other features
• Ext4 supports online defragmentation
• There's a e4defrag tool which can defragment
individual files or the whole filesystem
• Fsck- In Ext4, at the end of each group's inode
table will be stored a list of unused inodes
(with a checksum, for safety), so fsck will not
check those inodes. The result is that total fsck
time improves from 2 to 20 times, depending
on the number of used inodes.
30. Difference between ext versions
Point ext2 ext3 ext4
Maximum
individual file size
16GB – 2TB 16GB – 2TB 16GB – 16TB
Maximum file
system size
2TB – 32TB 2TB – 32TB 1EB
Journalling Not available Available Available and can
be turned “off” too
Number of
directories
31998 31998 Unlimited
Journal checksum No No Yes
Multi-block
allocation and
delayed allocation
No No Yes
31. Conclusion
• Linux file system follows the FSH standard
• Ext, ext2, ext3, ext4 are the versions of the ext
file system
• Ext is no longer supported by Linux kernel
• Ext4 filesystem supports 48-bit block
addressing, multi-block allocation, extents,
persistent pre-allocation, delayed allocation,
unlimited number of subdirectories, journal
checksumming and improved timestamps.
32. References
[1] ”Design and Implementation of the Seconded Extended
Filesystem”, Remy Card, Proceedings of the First Dutch
International Symposium on Linux, ISBN 9036703859
[2] Ext4 Linux Kernal Newbies – Online Documentation
[3] Introduction to Linux : Chapter 3 – General Overview of the
Linux Filesystem
[4] ”Ext4 block and inode allocator improvements”, Aneesh
Kumar et al, Proceesings of the Linux Symposium, 2008
[5] Linux Filesystem Hierarchy, Binh Nguyen
[6] www.tldp.org_LDP_tlk_fs_filesystem
[7] www.wikipedia.org – ext2, ext3, ext4