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Hard Link
In computing, a hard link is a directory entry (in a Directory (computing), directory-based file system) that associates a name with a Computer file, file. Thus, each file must have at least one hard link. Creating additional hard links for a file makes the contents of that file accessible via additional Path (computing), paths (i.e., via different names or in different directories). This causes an Aliasing (computing), alias effect: a process can open the file by any one of its paths and change its content. By contrast, a soft link or File shortcut, “shortcut” to a file is not a direct link to the data itself, but rather a reference to a hard link or another soft link. Every directory is itself a special file on many systems, containing a list of file names instead of other data. Hence, multiple hard links to directories are possible, which could create a circular directory structure, rather than a branching structure like a Tree structure, tree. For that reason, some file sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computing
Computing is any goal-oriented activity requiring, benefiting from, or creating computer, computing machinery. It includes the study and experimentation of algorithmic processes, and the development of both computer hardware, hardware and software. Computing has scientific, engineering, mathematical, technological, and social aspects. Major computing disciplines include computer engineering, computer science, cybersecurity, data science, information systems, information technology, and software engineering. The term ''computing'' is also synonymous with counting and calculation, calculating. In earlier times, it was used in reference to the action performed by Mechanical computer, mechanical computing machines, and before that, to Computer (occupation), human computers. History The history of computing is longer than the history of computing hardware and includes the history of methods intended for pen and paper (or for chalk and slate) with or without the aid of tables. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ReFS
Resilient File System (ReFS), codenamed "Protogon", is a Microsoft proprietary file system introduced with Windows Server 2012 with the intent of becoming the "next generation" file system after NTFS. ReFS was designed to overcome problems that had become significant over the years since NTFS was conceived, which are related to how data storage requirements have changed. These requirements arose from two major changes in storage systems and usage – the size of storage in use ( large or massive arrays of multi-terabyte drives now common), and the need for continual reliability. As a result, the file system needs to be self-repairing (to prevent disk checking from being impractically slow or disruptive), along with abstraction or virtualization between physical disks and logical volumes. The key design advantages of ReFS include automatic integrity checking and data scrubbing, elimination of the need for running chkdsk, protection against data degradation, bui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UNIX System V
Unix System V (pronounced: "System Five") is one of the first commercial versions of the Unix operating system. It was originally developed by AT&T and first released in 1983. Four major versions of System V were released, numbered 1, 2, 3, and 4. System V Release 4 (SVR4) was commercially the most successful version, being the result of an effort, marketed as ''Unix System Unification'', which solicited the collaboration of the major Unix vendors. It was the source of several common commercial Unix features. System V is sometimes abbreviated to SysV. , the AT&T-derived Unix market is divided between four System V variants: IBM's AIX, Hewlett Packard Enterprise's HP-UX and Oracle's Solaris, plus the free-software illumos forked from OpenSolaris. Overview Introduction System V was the successor to 1982's UNIX System III. While AT&T developed and sold hardware that ran System V, most customers ran a version from a reseller, based on AT&T's reference implementation. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stat (Unix)
is a Unix system call that queries the file system for metadata about a computer file, file (including Unix file type, special files such as computer directory, directories). The metadata contains many fields including Unix file type, type, file size, size, ownership, File-system permissions, permissions and Unix time, timestamps. For example, the ls, command uses this system call to retrieve timestamps: * mtime: when last modified () * atime: when last accessed () * ctime: when last status changed () appeared in Research Unix#Versions, Version 1 Unix. It is among the few original Unix system calls to change, with Research Unix#Versions, Version 4's addition of group permissions and larger file size. Since at least 2004, the same-named shell (computing), shell command (computing), command stat has been available for Linux to expose features of the system call via a command-line interface. Functions The C POSIX library header , found on POSIX and other Unix-like operating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inode
An inode (index node) is a data structure in a Unix-style file system that describes a file-system object such as a file or a directory. Each inode stores the attributes and disk block locations of the object's data. File-system object attributes may include metadata (times of last change, access, modification), as well as owner and permission data. A directory is a list of inodes with their assigned names. The list includes an entry for itself, its parent, and each of its children. Etymology There has been uncertainty on the Linux kernel mailing list about the reason for the "i" in "inode". In 2002, the question was brought to Unix pioneer Dennis Ritchie, who replied: A 1978 paper by Ritchie and Ken Thompson bolsters the notion of "index" being the etymological origin of inodes. They wrote: Additionally, Maurice J. Bach wrote that the word ''inode'' "is a contraction of the term index node and is commonly used in literature on the UNIX system". Details A file system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Undelete
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. Support Not all file systems or operating systems support undeletion. Undeletion is possible on all FAT file systems, with undeletion utilities provided since MS-DOS 5.0 and DR DOS 6.0 in 1991. It is not supported by most modern UNIX file systems, though AdvFS is a notable exception. The ext2 file system has an add-on program called e2undel which allows file undeletion. The similar ext3 file system does not officially support undeletion, but utilities like ext4magic, extundelete, Ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data
Data ( , ) are a collection of discrete or continuous values that convey information, describing the quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted formally. A datum is an individual value in a collection of data. Data are usually organized into structures such as tables that provide additional context and meaning, and may themselves be used as data in larger structures. Data may be used as variables in a computational process. Data may represent abstract ideas or concrete measurements. Data are commonly used in scientific research, economics, and virtually every other form of human organizational activity. Examples of data sets include price indices (such as the consumer price index), unemployment rates, literacy rates, and census data. In this context, data represent the raw facts and figures from which useful information can be extracted. Data are collected using technique ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integer
An integer is the number zero (0), a positive natural number (1, 2, 3, ...), or the negation of a positive natural number (−1, −2, −3, ...). The negations or additive inverses of the positive natural numbers are referred to as negative integers. The set (mathematics), set of all integers is often denoted by the boldface or blackboard bold The set of natural numbers \mathbb is a subset of \mathbb, which in turn is a subset of the set of all rational numbers \mathbb, itself a subset of the real numbers \mathbb. Like the set of natural numbers, the set of integers \mathbb is Countable set, countably infinite. An integer may be regarded as a real number that can be written without a fraction, fractional component. For example, 21, 4, 0, and −2048 are integers, while 9.75, , 5/4, and Square root of 2, are not. The integers form the smallest Group (mathematics), group and the smallest ring (mathematics), ring containing the natural numbers. In algebraic number theory, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reference Counting
In computer science, reference counting is a programming technique of storing the number of references, pointers, or handles to a resource, such as an object, a block of memory, disk space, and others. In garbage collection algorithms, reference counts may be used to deallocate objects that are no longer needed. Advantages and disadvantages The main advantage of the reference counting over tracing garbage collection is that objects are reclaimed ''as soon as'' they can no longer be referenced, and in an incremental fashion, without long pauses for collection cycles and with clearly defined lifetime of every object. In real-time applications or systems with limited memory, this is important to maintain responsiveness. Reference counting is also among the simplest forms of memory management to implement. It also allows for effective management of non-memory resources such as operating system objects, which are often much scarcer than memory (tracing garbage collection systems ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simplified Illustration Of Hard Links On Typical UN*X Filesystem
Simplification, Simplify, or Simplified may refer to: Mathematics Simplification is the process of replacing a mathematical expression by an equivalent one that is simpler (usually shorter), according to a well-founded ordering. Examples include: * Simplification of algebraic expressions, in computer algebra * Simplification of boolean expressions i.e. logic optimization * Simplification by conjunction elimination in inference in logic yields a simpler, but generally non-equivalent formula * Simplification of fractions Science * Approximations simplify a more detailed or difficult to use process or model Linguistics * Simplification of Chinese characters * Simplified English (other) * Text simplification Music * ''Simplify'', a 1999 album by Ryan Shupe & the RubberBand * Simplified (band), a 2002 rock band from Charlotte, North Carolina * ''Simplified'' (album), a 2005 album by Simply Red * "Simplify", a 2008 song by Sanguine * "Simplify", a 2018 song by Young the G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GNU Emacs
GNU Emacs is a text editor and suite of free software tools. Its development began in 1984 by GNU Project founder Richard Stallman, based on the Emacs editor developed for Unix operating systems. GNU Emacs has been a central component of the GNU project and a flagship project of the free software movement. The program's tagline is "the extensible self-documenting text editor." Most functionality in GNU Emacs is implemented in user-accessible Emacs Lisp, allowing deep extensibility directly by users and through community-contributed packages. Its built-in features include a file browser and editor (Dired), an advanced calculator (Calc), an email client and news reader (Gnus), a Language Server Protocol integration, and the productivity system Org-mode. A large community of users have contributed extensions such as the Git interface Magit, the Vim (text editor), Vim emulation layer Evil, several search frameworks, the window manager EXWM, and tools for working with a wide range of p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Text Editor
A text editor is a type of computer program that edits plain text. An example of such program is "notepad" software (e.g. Windows Notepad). Text editors are provided with operating systems and software development packages, and can be used to change files such as configuration files, documentation files and programming language source code. Plain text and rich text There are important differences between plain text (created and edited by text editors) and rich text (such as that created by word processors or desktop publishing software). Plain text exclusively consists of character representation. Each character is represented by a fixed-length sequence of one, two, or four bytes, or as a variable-length sequence of one to four bytes, in accordance to specific character encoding conventions, such as ASCII, ISO/IEC 2022, ISO/IEC 2022, Shift JIS, UTF-8, or UTF-16. These conventions define many printable characters, but also whitespace character, non-printing characters th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
