Identifying Files - Revision history

Dan Tobias: /* MIME Type */

2017-02-21T00:55:23Z

‎MIME Type

Jsummers: Reorganizing, and merging from Category:File_Format_Identification.

2015-08-16T21:22:08Z

Reorganizing, and merging from Category:File_Format_Identification.

Jsummers: Category:File Format Identification

2015-06-25T22:53:58Z

Category:File Format Identification

Rhetoric X: File identification software

2012-10-28T16:08:31Z

File identification software

JasonAller: first draft

2012-10-28T10:23:09Z

first draft

New page

Once you have retrieved a file from its storage media you'll need to identify what kind of information you now have access to. In some cases like a phonograph record that has lost its label you may have to find an expert on the media contained on the device to identify what song you now have. However when working with files generated by computer there are several clues you can use to begin the process.

== File Extension ==
One of the best places to start if working with a file that is still stored under its original file name is to look at the extension. For many operating systems this will be the characters at the end of the name, often separated by a period. OFFICE.DXF would be a file of with a .DXF extension which we could use to discover it is likely an AutoCad file most likely storing a drafting drawing.

== Creator and Type ==
The Macintosh from Apple did not use file extensions, but instead used 4 character creator and type codes.

== Text Editor ==
Opening the file with a text editor may yield clues as to the content, even if the contents can not be interpreted by reading visually. An example would be opening .png files with a text editor; even without the file extension the second through fourth character will be "PNG".

== Hex Editor ==
Some file types have a recognizable signature when viewed with a hexadecimal editor.

@@ Line 9: / Line 9: @@
 === MIME Type ===
-Some systems, such as [[HTTP]] and [[MIME]], use [[Mime-type]]s to identify a file's data type. However, Mime-types are of marginal use for identifying rare file types to humans. They may have been guessed from the file's filename extension or magic signature, which provides no new information.
+Some systems, such as [[HTTP]] and [[MIME]], use [[MIME types]] to identify a file's data type. However, Mime-types are of marginal use for identifying rare file types to humans. They may have been guessed from the file's filename extension or magic signature, which provides no new information.
 == Internal signatures ==

@@ Line 1: / Line 1: @@
-Once you have retrieved a file from its storage media you'll need to identify what kind of information you now have access to. In some cases like a phonograph record that has lost its label you may have to find an expert on the media contained on the device to identify what song you now have. However when working with files generated by computer there are several clues you can use to begin the process.
+Once you have retrieved a file from its storage media, you'll need to identify what kind of information you now have access to. In some cases, like a phonograph record that has lost its label, you may have to find an expert on the media contained on the device to identify what song you now have (see [[Identifying Physical Media]]). However, when working with files generated by computer, there are several clues you can use to begin the process.
-== File Extension ==
+== External signatures ==
 One of the best places to start if working with a file that is still stored under its original file name is to look at the extension. For many operating systems this will be the characters at the end of the name, often separated by a period. OFFICE.DXF would be a file of with a .DXF extension which we could use to discover it is likely an AutoCad file most likely storing a drafting drawing.
-== Creator and Type ==
+=== Creator and Type ===
 The Macintosh from Apple did not use file extensions, but instead used 4 character creator and type codes.
-== Software Utilities ==
+=== MIME Type ===
-There are software utilities that are able to identify file types. See [[file identification software]].
+Some systems, such as [[HTTP]] and [[MIME]], use [[Mime-type]]s to identify a file's data type. However, Mime-types are of marginal use for identifying rare file types to humans. They may have been guessed from the file's filename extension or magic signature, which provides no new information.
-== Text Editor ==
+== Internal signatures ==
-Opening the file with a text editor may yield clues as to the content, even if the contents can not be interpreted by reading visually. An example would be opening .png files with a text editor; even without the file extension the second through fourth character will be "PNG".
+An internal signature is a distinctive pattern of bytes in the file's contents. Most often, it takes the form of a "magic signature" near the beginning of the file.
-== Hex Editor ==
+See [[File identification software]] for utilities that can help to identify files using such signatures.
-Some file types have a recognizable signature when viewed with a hexadecimal editor.
 [[Category:File Format Identification]]

← Older revision		Revision as of 22:53, 25 June 2015
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	== Hex Editor ==		== Hex Editor ==
	Some file types have a recognizable signature when viewed with a hexadecimal editor.		Some file types have a recognizable signature when viewed with a hexadecimal editor.
		+
		+	[[Category:File Format Identification]]