Editing Computer file (section)

=== File size ===
{{Misleading|section|date=March 2019}}
{{Main article|File size}}

At any instant in time, a file has a specific size, normally expressed as a number of [[byte]]s,<ref group="lower-alpha">Can also be shown as kilobytes, megabytes, gigabytes, etc.</ref> that indicates how much storage is occupied by the file. In most modern operating systems the size can be any non-negative whole number of bytes up to a system limit. Many older operating systems kept track only of the number of [[disk sector|blocks]] or [[track (disk drive)|tracks]] occupied by a file on a physical storage device. 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).

The general definition of a file does not require that its size have any real meaning, however, unless the data within the file happens to correspond to data within a pool of persistent storage. 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 (computing)|flag]] in the file system, or are accidents (the results of aborted disk operations). For example, the file to which the link {{Mono|/bin/ls}} points in a typical [[Unix-like]] system probably has a defined size that seldom changes. Compare this with {{Mono|[[/dev/null]]}} which is also a file, but as a [[character special file]], its size is not meaningful.