A data file is a computer file which stores data for use by a computer application or system. It generally does not refer to files that contain instructions or code to be executed (typically called program files), or to files which define the operation or structure of an application or system (which include configuration files, directory files, etc.); but specifically to information used as input, and/or written as output by some other software program.

Data files come in two broad categories: open and closed.

Closed data file formats

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Closed data (frequently referred to as proprietary format files) files have their metadata data elements hidden, obsured or unavailable to users of the file. Application developers do this to discourage users from tampering or corrupting with the data files or importing the data into a competitors application. See vendor lock-in.

Open data file formats

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Open data files have their the their internal structures available to users of the through a process of metadata publishing. Metadata publishing implies that the structure and semantics of all the possible data elements within a file are availalbe to users.

Examples of open data files include XML formats such as HTML for storing web pages or SVG for storing scalable graphics.

Binary and ASCII data file formats

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Data files are frequently stored in binary or ASCII file formats. ASCII file formats can usually be inspected and modified with an appropriate text or word-processor.

Binary files are usually not editable with a text or word processor.

Note that binary file formats are not necessarily closed. Some application vendors store data in a compressed file structure.

See also

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• Index file
• Database

Computer file systems