ext2, or second extended file system, is a file system for the Linux kernel. It was initially designed by French software developer Rémy Card as a replacement for the extended file system (ext). Having been designed according to the same principles as the Berkeley Fast File System from BSD, it was the first commercial-grade filesystem for Linux.
ext3, or third extended filesystem, is a journaled file system that is commonly used with the Linux kernel. It used to be the default file system for many popular Linux distributions but generally has been supplanted by its successor version ext4. The main advantage of ext3 over its predecessor, ext2, is journaling, which improves reliability and eliminates the need to check the file system after an improper, a.k.a. unclean, shutdown.
Disk partitioning or disk slicing is the creation of one or more regions on secondary storage, so that each region can be managed separately. These regions are called partitions. It is typically the first step of preparing a newly installed disk after a partitioning scheme is chosen for the new disk before any file system is created. The disk stores the information about the partitions' locations and sizes in an area known as the partition table that the operating system reads before any other part of the disk. Each partition then appears to the operating system as a distinct "logical" disk that uses part of the actual disk. System administrators use a program called a partition editor to create, resize, delete, and manipulate the partitions. Partitioning allows the use of different filesystems to be installed for different kinds of files. Separating user data from system data can prevent the system partition from becoming full and rendering the system unusable. Partitioning can also make backing up easier. A disadvantage is that it can be difficult to properly size partitions, resulting in having one partition with too much free space and another nearly totally allocated.
In the maintenance of file systems, defragmentation is a process that reduces the degree of fragmentation. It does this by physically organizing the contents of the mass storage device used to store files into the smallest number of contiguous regions. It also attempts to create larger regions of free space using compaction to impede the return of fragmentation. Some defragmentation utilities try to keep smaller files within a single directory together, as they are often accessed in sequence.
SystemRescue is a Linux distribution for x86-64 and IA-32 computers. The primary purpose of SystemRescue is to repair unbootable or otherwise damaged computer systems after a system crash. SystemRescue is not intended to be used as a permanent operating system. It runs from a Live CD, a USB flash drive or any type of hard drive. It was designed by a team led by François Dupoux, and is based on Arch Linux since version 6.0. Starting with version 6.0, it has systemd as its init system.
Multi-booting is the act of installing multiple operating systems on a single computer, and being able to choose which one to boot. The term dual-booting refers to the common configuration of specifically two operating systems. Multi-booting may require a custom boot loader.
GHOST, now called Symantec™ GHOST Solution Suite (GSS) for enterprise, is a disk cloning and backup tool originally developed by Murray Haszard in 1995 for Binary Research. The technology was bought in 1998 by Symantec.
The Installable File System (IFS) is a filesystem API in MS-DOS/PC DOS 4.x, IBM OS/2 and Microsoft Windows that enables the operating system to recognize and load drivers for file systems.
In computing, a file system or filesystem governs file organization and access. A local file system is a capability of an operating system that services the applications running on the same computer. A distributed file system is a protocol that provides file access between networked computers.
The USB mass storage device class is a set of computing communications protocols, specifically a USB Device Class, defined by the USB Implementers Forum that makes a USB device accessible to a host computing device and enables file transfers between the host and the USB device. To a host, the USB device acts as an external hard drive; the protocol set interfaces with a number of storage devices.
In computing, an extent is a contiguous area of storage reserved for a file in a file system, represented as a range of block numbers, or tracks on count key data devices. A file can consist of zero or more extents; one file fragment requires one extent. The direct benefit is in storing each range compactly as two numbers, instead of canonically storing every block number in the range. Also, extent allocation results in less file fragmentation.
Undeletion is a feature for restoring computer files which have been removed from a file system by file deletion. Deleted data can be recovered on many file systems, but not all file systems provide an undeletion feature. Recovering data without an undeletion facility is usually called data recovery, rather than undeletion. Undeletion can both help prevent users from accidentally losing data, or can pose a computer security risk, since users may not be aware that deleted files remain accessible.
GParted is a GTK front-end to GNU Parted and an official GNOME partition-editing application. GParted is used for creating, deleting, resizing, moving, checking, and copying disk partitions and their file systems. This is useful for creating space for new operating systems, reorganizing disk usage, copying data residing on hard disks, and mirroring one partition with another. It can also be used to format a USB drive.
The following tables compare general and technical information for a number of file systems.
ext4 is a journaling file system for Linux, developed as the successor to ext3.
Partimage is a disk cloning utility for Linux/UNIX environments. Partimage can save partitions in many formats to a disk image. Utilities such as Partimage are useful in a number of situations which are commonly encountered by network administrators as well as advanced computer users who maintain their own systems. The last stable release was in 2010; since then, one of Partimage's authors has worked on FSArchiver, which has broader functionality than Partimage.
dm-crypt is a transparent block device encryption subsystem in Linux kernel versions 2.6 and later and in DragonFly BSD. It is part of the device mapper (dm) infrastructure, and uses cryptographic routines from the kernel's Crypto API. Unlike its predecessor cryptoloop, dm-crypt was designed to support advanced modes of operation, such as XTS, LRW and ESSIV, in order to avoid watermarking attacks. In addition to that, dm-crypt addresses some reliability problems of cryptoloop.
In computer operating systems, mkfs is a command used to format a block storage device with a specific file system. The command is part of Unix and Unix-like operating systems. In Unix, a block storage device must be formatted with a file system before it can be mounted and accessed through the operating system's filesystem hierarchy.
Recuva is an undeletion program for Windows, developed by Piriform Software.
Partition-Saving is a disk imaging utility for Linux, Windows and DOS environments that can save disk partitions in one of the several supported disk image formats.
