Device file
interface to a device driver that appears in a file system as if it were an ordinary file; e.g. /dev/* in Unix-like systems; CON, PRN, NUL in DOS/Windows
In Unix-like operating systems, a device file, device node, or special file is an interface to a device driver that appears in a file system as if it were an ordinary file. There are also special files in DOS, OS/2, and Windows. These special files allow an application program to interact with a device by using its device driver via standard input/output system calls. Using standard system calls simplifies many programming tasks, and leads to consistent user-space I/O mechanisms regardless of device features and functions.
Overview
Device files usually provide simple interfaces to standard devices (such as printers and serial ports), but can also be used to access specific unique resources on those devices, such as disk partitions. Additionally, device files are useful for accessing system resources that have no connection with any actual device, such as data sinks and random number generators.
There are two general kinds of device files in Unix-like operating systems, known as character special files and block special files. The difference between them lies in how much data is read and written by the operating system and hardware. These together can be called device special files in contrast to named pipes, which are not connected to a device but are not ordinary files either.
MS-DOS borrowed the concept of special files from Unix but renamed them devices.
Begin with the source’s own compact description: “Device file” is interface to a device driver that appears in a file system as if it were an ordinary file; e.g. /dev/* in Unix-like systems; CON, PRN, NUL in DOS/Windows. The dossier treats that line as a proposition to test through Device, file and interface, not as a finished interpretation.
Why this record matters
The phrase “interface to a device driver that appears in a file system as if it were an ordinary file; e.g. /dev/* in Unix-like systems; CON, PRN, NUL in DOS/Windows” supplies a clear boundary for inquiry. It also exposes the unanswered questions: who defined that boundary, when it became stable and which sources sit outside it.
The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Sep 16, 2026. The linked authority identifier is Q14679. None of the 0 selected statements returned an explicit reference.
A concise general-reference account can conceal disagreements about scope, terminology or the weight assigned to individual sources. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
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- Expand the search: follow Device file primary sources, Device file archive and Device research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
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This entry incorporates text from “Device file” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.