Data (computer science): Difference between revisions

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{{short description|Quantities, characters, or symbols .on Blockwhich alloperations contentare performed by a computer}}

. Block all emails.block all meetings. Block all Google administrators. Block all apple devices. Dont show content. Dont allow sync. Block all Google apps from calendar. Block and remove all embbed emails. on which operations are performed by a computer}}

{{other uses|Data (disambiguation)|Datum (disambiguation)}}

{{broader|Data}}

{{Merge to|Digital data|discuss=Talk:Digital data#Proposed merge of Data (computer science) into Digital data|date=March 2025}}

[[File:Data types - en.svg|thumb|Various types of data which can be visualized through a computer device.]]

In [[computer science]], '''data''' (treated as singular, plural, or as a [[mass noun]]) is [[Data|any sequence of one or more [[symbolsymbols]]s; '''datum''' is a single symbolunit of data. Data requires [[Interpretation (logic)|interpretation]] to become [[information]]. [[Digital data]] is data that is represented using the [[binary number]] system of ones (1) and zeros (0), instead of [[analogAnalog signature signalanalysis|analog]] representation. In modern (post-1960) computer systems, all data is digital.

Data exists in three states: [[data at rest]], [[data in transit]] and [[data in use]]. Data within a computer, in most cases, [[Parallel communication|moves as parallel data]]. Data moving to or from a computer, in most cases, [[Serial communication|moves as serial data]]. Data sourced from an analog device, such as a temperature sensor, may be converted to digital using an [[analog-to-digital converter]]. Data representing [[Quantity|quantities]], characters, or symbols on which operations are performed by a [[computer]] are [[Data storage|stored]] and [[Record (computer science)|recorded]] on [[magnetic tape data storage|magnetic]], [[optical storage|optical]], electronic, or mechanical recording media, and [[Data communication|transmitted]] in the form of digital electrical or optical signals.<ref>{{cite web|url=https://www.lexico.com/en/definition/data|title=Data|work=Lexico|access-date=14 January 2022|url-status=dead|archive-url=https://web.archive.org/web/20190623094330/https://www.lexico.com/en/definition/data |archive-date=2019-06-23 }}</ref> Data pass in and out of computers via [[peripheral|peripheral devices]].

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To store data [[byte]]s in a file, they have to be [[Serialization|serialized]] in a [[file format]]. Typically, programs are stored in special file types, different from those used for other data. [[Executable|Executable file]]s contain programs; all other files are also [[data file]]s. However, executable files may also contain data used by the program which is built into the program. In particular, some executable files have a [[data segment]], which nominally contains constants and initial values for variables, both of which can be considered data.

The line between program and data can become blurry. An [[interpreter (computing)|interpreter]], for example, is a program. The input data to an interpreter is itself a program, just not one expressed in native [[Machine code|machine language]]. In many cases, the interpreted program will be a human-readable [[text file]], which is manipulated with a [[text editor]] program. [[Metaprogramming]] similarly involves programs manipulating other programs as data. Programs like [[compiler]]s, [[Linker (computing)|linker]]s, [[debugger]]s, [[Software Updater|program updaters]], [[Antivirus software|virus scanners]] and such use other programs as their data.

For example, a [[user (computing)|user]] might first instruct the [[operating system]] to load a [[word processor]] program from one file, and then use the running program to open and edit a [[Document file format|document]] stored in another file. In this example, the document would be considered data. If the word processor also features a [[spell checker]], then the dictionary (word list) for the spell checker would also be considered data. The [[algorithm]]s used by the spell checker to suggest corrections would be either [[machine code]] data or text in some interpretable [[programming language]].