Computer file

filefilescomputer fileselectronicelectronic filedata filedata sourcesdigital filecontentdata files
A computer file is a computer resource for recording data discretely in a computer storage device.wikipedia
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File format

formatfile formatsformats
There are different types of computer files, designed for different purposes. The format of a file is defined by its content since a file is solely a container for data, although on some platforms the format is usually indicated by its filename extension, specifying the rules for how the bytes must be organized and interpreted meaningfully.
A file format is a standard way that information is encoded for storage in a computer file.

System resource

resourcesresourcesystem resources
A computer file is a computer resource for recording data discretely in a computer storage device.
Virtual system resources include files (concretely file handles), network connections (concretely network sockets), and memory areas.

File system

filesystemfile systemsfilesystems
Typically, files are organised in a file system, which keeps track of where the files are located on disk and enables user access. The introduction, circa 1961, by the Burroughs MCP and the MIT Compatible Time-Sharing System of the concept of a "file system" that managed several virtual "files" on one storage device is the origin of the contemporary denotation of the word.
Taking its name from the way paper-based information systems are named, each group of data is called a "file".

Filename extension

file extensionextensionfile extensions
The format of a file is defined by its content since a file is solely a container for data, although on some platforms the format is usually indicated by its filename extension, specifying the rules for how the bytes must be organized and interpreted meaningfully.
A filename extension is an identifier specified as a suffix to the name of a computer file.

Extended file attributes

extended attributesextended attributeextended file attribute
Some file systems can store arbitrary (not interpreted by the file system) file-specific data outside of the file format, but linked to the file, for example extended attributes or forks.
Extended file attributes are file system features that enable users to associate computer files with metadata not interpreted by the filesystem, whereas regular attributes have a purpose strictly defined by the filesystem (such as permissions or records of creation and modification times).

Sidecar file

Media Descriptor Sidecar file
On other file systems this can be done via sidecar files or software-specific databases.
Sidecar files, also known as buddy files or connected files, are computer files that store data (often metadata) which is not supported by the format of a source file.

Metadata

meta datameta-datacommunications metadata
Most file types also allocate a few bytes for metadata, which allows a file to carry some basic information about itself.
Describing the contents and context of data or data files increases its usefulness.

Digital container format

container formatcontainercontainer formats
All those methods, however, are more susceptible to loss of metadata than are container and archive file formats.
A container or wrapper format is a metafile format whose specification describes how different elements of data and metadata coexist in a computer file.

Computer data storage

main memorystoragememory
A computer file is a computer resource for recording data discretely in a computer storage device.
Secondary storage is often formatted according to a file system format, which provides the abstraction necessary to organize data into files and directories, while also providing metadata describing the owner of a certain file, the access time, the access permissions, and other information.

Zero-byte file

zero byte file
A special case is a zero byte file; these files can be newly created files that have not yet had any data written to them, or may serve as some kind of flag in the file system, or are accidents (the results of aborted disk operations).
A zero-byte file or zero-length file is a computer file containing no data; that is, it has a length or size of zero bytes.

Device file

block devicedevice nodepseudo-device
Compare this with /dev/null which is also a file, but as a character special file, its size is not meaningful.
In Unix-like operating systems, a device file or special file is an interface to a device driver that appears in a file system as if it were an ordinary file.

CP/M

CP/M-80CP/M operating systemBDOS
In such systems, software employed other methods to track the exact byte count (e.g., CP/M used a special control character, Ctrl-Z, to signal the end of text files).

Hard link

hard linkshardlink
For example, rm filename will not delete the file itself, but only a link to the file.
In computing, a hard link is a directory entry that associates a name with a file on a file system.

Inode

inode numberinodesinode table
The operating system provides a level of abstraction, which means that interaction with a file from user-space is simply through its filename (instead of its inode).
The 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.

Data remanence

data left on storageData purgingdata shredding
This free space is commonly considered a security risk (due to the existence of file recovery software).
Many operating systems, file managers, and other software provide a facility where a file is not immediately deleted when the user requests that action.

Rm (Unix)

rmdeletedrm -rf
For example, rm filename will not delete the file itself, but only a link to the file.
In computing, (short for remove) is a basic command on Unix and Unix-like operating systems used to remove objects such as computer files, directories and symbolic links from file systems and also special files such as device nodes, pipes and sockets, similar to the command in MS-DOS, OS/2, and Microsoft Windows.

File attribute

attributesattributefile attributes
File attributes are metadata associated with computer files that define file system behavior.

Filename

file namename6.3 filename
In modern computer systems, files are typically accessed using names (filenames).
A filename (also written as two words, file name) is a name used to uniquely identify a computer file stored in a file system.

Compatible Time-Sharing System

CTSSCompatible Time Sharing System
The introduction, circa 1961, by the Burroughs MCP and the MIT Compatible Time-Sharing System of the concept of a "file system" that managed several virtual "files" on one storage device is the origin of the contemporary denotation of the word.
Each file had two names, the second name was similar to extension today.

Directory (computing)

directorydirectoriesfolder
However, more generally, a directory can contain either a list of files or a list of links to files.
In computing, a directory is a file system cataloging structure which contains references to other computer files, and possibly other directories.

Microsoft Word

WordMS WordWord for Windows
For instance, Microsoft Word files are normally created and modified by the Microsoft Word program in response to user commands, but the user can also move, rename, or delete these files directly by using a file manager program such as Windows Explorer (on Windows computers) or by command lines (CLI).
As with all OLE Compound Files, Word Binary Format consists of "storages", which are analogous to computer folders, and "streams", which are similar to computer files.

Open (system call)

open system call
For most file systems, a program initializes access to a file in a file system using the open system call.

Operating system

operating systemsOScomputer operating system
The operating system provides a level of abstraction, which means that interaction with a file from user-space is simply through its filename (instead of its inode). On most modern operating systems, files are organized into one-dimensional arrays of bytes.
Computers store data on disks using files, which are structured in specific ways in order to allow for faster access, higher reliability, and to make better use of the drive's available space.

Read (system call)

read
In modern POSIX compliant operating systems, a program that needs to access data from a file stored in a file system uses the read system call.

Hidden file and hidden directory

hidden filehiddendotfile
Some systems also include a hidden flag to make certain files invisible; this flag is used by the computer system to hide essential system files that users should not alter.
In computing, a hidden folder (sometimes hidden directory) or hidden file is a folder or file which filesystem utilities do not display by default when showing a directory listing.