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Tux3
Tux3 is an open-source versioning filesystem created by Daniel Phillips. He introduced the filesystem as a public replacement for his Tux2 filesystem which had encountered licensing issues due to the filing of several patents. Phillips had previously created the Htree directory indexing system which eventually became an official feature of ext3. The technical details of Tux3 were first publicized in an email on 23 July 2008. Design In broad outline, Tux3 follows a conventional Unix-style inode/file/directory design. A Tux3 inode table is a B-tree with versioned attributes at the leaves. A file is an inode attribute that is a B-tree with versioned extents at the leaves. Directory indexes are mapped into directory file blocks as with Htree. Free space is mapped by a B-tree with extents at the leaves. It attempts to avoid traditional journaling by introducing a recovery logic which allows it to recover upon remounting. A Tux3 inode is a variable sized object consisting of a list ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Htree
An HTree is a specialized tree data structure for directory indexing, similar to a B-tree. They are constant depth of either one or two levels, have a high fanout factor, use a hash of the filename, and do not require balancing. The HTree algorithm is distinguished from standard B-tree methods by its treatment of hash collisions, which may overflow across multiple leaf and index blocks. HTree indexes are used in the ext3 and ext4 Linux filesystems, and were incorporated into the Linux kernel around 2.5.40. HTree indexing improved the scalability of Linux ext2 based filesystems from a practical limit of a few thousand files, into the range of tens of millions of files per directory. History The HTree index data structure and algorithm were developed by Daniel Phillips in 2000 and implemented for the ext2 filesystem in February 2001. A port to the ext3 filesystem by Christopher Li and Andrew Morton in 2002 during the 2.5 kernel series added journal based crash consistency. With ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PHTree
An HTree is a specialized tree data structure for directory indexing, similar to a B-tree. They are constant depth of either one or two levels, have a high fanout factor, use a hash of the filename, and do not require balancing. The HTree algorithm is distinguished from standard B-tree methods by its treatment of hash collisions, which may overflow across multiple leaf and index blocks. HTree indexes are used in the ext3 and ext4 Linux filesystems, and were incorporated into the Linux kernel around 2.5.40. HTree indexing improved the scalability of Linux ext2 based filesystems from a practical limit of a few thousand files, into the range of tens of millions of files per directory. History The HTree index data structure and algorithm were developed by Daniel Phillips in 2000 and implemented for the ext2 filesystem in February 2001. A port to the ext3 filesystem by Christopher Li and Andrew Morton in 2002 during the 2.5 kernel series added journal based crash consistency. W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Versioning Filesystem
A versioning file system is any computer file system which allows a computer file to exist in several versions at the same time. Thus it is a form of revision control. Most common versioning file systems keep a number of old copies of the file. Some limit the number of changes per minute or per hour to avoid storing large numbers of trivial changes. Others instead take periodic snapshots whose contents can be accessed with similar semantics to normal file access. Similar technologies Backup A versioning file system is similar to a periodic backup, with several key differences. * Backups are normally triggered on a timed basis, while versioning occurs when the file changes. * Backups are usually system-wide or partition-wide, while versioning occurs independently on a file-by-file basis. * Backups are normally written to separate media, while versioning file systems write to the same hard drive (and normally the same folder, directory, or local partition). In comparison t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of File Systems
The following lists identify, characterize, and link to more thorough information on Computer file systems. Many older operating systems support only their one "native" file system, which does not bear any name apart from the name of the operating system itself. Disk file systems Disk file systems are usually block-oriented. Files in a block-oriented file system are sequences of blocks, often featuring fully random-access read, write, and modify operations. * ADFS – Acorn's Advanced Disc filing system, successor to DFS. * AdvFS – Advanced File System, designed by Digital Equipment Corporation for their Digital UNIX (now Tru64 UNIX) operating system. * APFS – Apple File System is a next-generation file system for Apple products. * AthFS – AtheOS File System, a 64-bit journaled filesystem now used by Syllable. Also called AFS. * BFS – the Boot File System used on System V release 4.0 and UnixWare. * BFS – the Be File System used on BeOS, occasionally misnamed as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linux
Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which includes the kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name "GNU/Linux" to emphasize the importance of GNU software, causing some controversy. Popular Linux distributions include Debian, Fedora Linux, and Ubuntu, the latter of which itself consists of many different distributions and modifications, including Lubuntu and Xubuntu. Commercial distributions include Red Hat Enterprise Linux and SUSE Linux Enterprise. Desktop Linux distributions include a windowing system such as X11 or Wayland, and a desktop environment such as GNOME or KDE Plasma. Distributions intended for ser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Btrfs
Btrfs (pronounced as "better F S", "butter F S", "b-tree F S", or simply by spelling it out) is a computer storage format that combines a file system based on the copy-on-write (COW) principle with a logical volume manager (not to be confused with Linux's LVM), developed together. It was initially designed at Oracle Corporation in 2007 for use in Linux, and since November 2013, the file system's on-disk format has been declared stable in the Linux kernel. According to Oracle, Btrfs "is not a true acronym". Btrfs is intended to address the lack of pooling, snapshots, checksums, and integral multi-device spanning in Linux file systems. Chris Mason, the principal Btrfs author, stated that its goal was "to let inuxscale for the storage that will be available. Scaling is not just about addressing the storage but also means being able to administer and to manage it with a clean interface that lets people see what's being used and makes it more reliable". History The core dat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linux Magazine
''Linux Magazine'' is an international magazine for Linux software enthusiasts and professionals. It is published by the former Linux New Media division of the German media company Medialinx AG. The magazine was first published in German in 1994, and later in English, Polish, Brazilian Portuguese, and Spanish. The German edition is called ''Linux-Magazin'' (); the American/Canadian edition is ''Linux Pro Magazine'' (). The founding company was Articon GmbH. The magazine is published on the first Thursday of each month. Every issue includes a DVD-ROM, usually featuring a recent version of a Linux distribution. ''Linux-Magazin'' ''Linux-Magazin'' is among the oldest magazines about Linux in the world. The first German language issue appeared in October 1994, seven months after ''Linux Journals first issue, as the information paper for DELUG, the German Linux user group. The slogan of the magazine is „Die Zeitschrift für Linux-Professionals“ (German for "The magazine for Lin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comparison Of File Systems
The following tables compare general and technical information for a number of file systems. General information Limits Metadata Features File capabilities Block capabilities Note that in addition to the below table, block capabilities can be implemented below the file system layer in Linux ( LVM, integritysetup, cryptsetup) or Windows (Volume Shadow Copy Service, SECURITY), etc. Resize capabilities "online" and "offline" are synonymous with "mounted" and "not mounted". Allocation and layout policies OS support See also * List of file systems * Comparison of file archivers * List of archive formats * Comparison of archive formats Notes References External links A speed comparison of filesystems on Linux 2.4.5(archived) Filesystems (ext3, reiser, xfs, jfs) comparison on Debian Etch{{Webarchive, url=https://web.archive.org/web/20180304191727/https://debian-administration.org/article/388/Filesystems_ext3_reiser_xfs_jfs_comparison ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
E2fsprogs
e2fsprogs (sometimes called the e2fs programs) is a set of utilities for maintaining the ext2, ext3 and ext4 file systems. Since those file systems are often the default for Linux distributions, it is commonly considered to be essential software. List of utilities Included with e2fsprogs, ordered by ASCIIbetical order, are: ;badblocks : search a device for bad blocks ;blkid : locate/print block device attributes ;chattr : change file attributes on a Linux file system ;debugfs : used to manually view or modify internal structures of the file system ;dumpe2fs : which prints superblock and block group information. ;e2freefrag : report free space fragmentation information ;e2fsck : an fsck program that checks for and corrects inconsistencies ;e2image : save critical ext2/ext3/ext4 filesystem metadata to a file ;e2label : change the label on an ext2/ext3/ext4 filesystem ;e2undo : replay an undo log for an ext2/ext3/ext4 filesystem ;e4defrag : online defragmenter for ext4 filesystem ;fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Referential Integrity
Referential integrity is a property of data stating that all its references are valid. In the context of relational databases, it requires that if a value of one attribute (column) of a relation (table) references a value of another attribute (either in the same or a different relation), then the referenced value must exist. For referential integrity to hold in a relational database, any column in a base table that is declared a foreign key can only contain either null values or values from a parent table's primary key or a candidate key. In other words, when a foreign key value is used it must reference a valid, existing primary key in the parent table. For instance, deleting a record that contains a value referred to by a foreign key in another table would break referential integrity. Some relational database management systems (RDBMS) can enforce referential integrity, normally either by deleting the foreign key rows as well to maintain integrity, or by returning an error and n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fsck
The system utility fsck (''file system consistency check'') is a tool for checking the consistency of a file system in Unix and Unix-like operating systems, such as Linux, macOS, and FreeBSD. A similar command, CHKDSK, exists in Microsoft Windows and its predecessor, MS-DOS. Pronunciation There is no agreed pronunciation. It can be pronounced "F-S-C-K", "F-S-check", "fizz-check", "F-sack", "fisk", "fishcake", "fizik", "F-sick", "F-sock", "F-sek", "feshk", the sibilant "fsk", "fix", "farsk" or "fusk". Use Generally, fsck is run either automatically at boot time, or manually by the system administrator. The command works directly on data structures stored on disk, which are internal and specific to the particular file system in use - so an fsck command tailored to the file system is generally required. The exact behaviors of various fsck implementations vary, but they typically follow a common order of internal operations and provide a common command-line interface to the user. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journaling File System
A journaling file system is a file system that keeps track of changes not yet committed to the file system's main part by recording the goal of such changes in a data structure known as a "journal", which is usually a circular log. In the event of a system crash or power failure, such file systems can be brought back online more quickly with a lower likelihood of becoming corrupted. Depending on the actual implementation, a journaling file system may only keep track of stored metadata, resulting in improved performance at the expense of increased possibility for data corruption. Alternatively, a journaling file system may track both stored data and related metadata, while some implementations allow selectable behavior in this regard. History In 1990 IBM introduced JFS in AIX 3.1 as one of the first UNIX commercial filesystems that implemented journaling. The next year the idea was popularized in a widely cited paper on log-structured file systems. This was subsequently i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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