File Extensions

by Fran Damratowski, Refurbishing SIG Chair
Chesapeake PC Users Group, MD
From the July, 2007 issue of the I/O Port Newsletter

Obtained from APCUG with the author's permission for publication by APCUG member groups.

Have you ever wondered what the three alphanumeric extension at the end of a file name mean. (MS-DOS required filename to limited to eight characters for the base or root name and three characters for the extension. Windows 95 and above no longer have that limitation.) The three or more letters or numbers are a way for the computer user, software, and operating system to differentiate between and identify the program used to create a file (document, spreadsheet, database, etc.). We are all familiar with .exe for an executable file, .txt for a text document, and .pdf for a PDF file. There are many other file extensions. The same file extension may be used for more than one program. There is no standard or organization for creating file extensions.

Here is a sampling of the B list of some of the extensions and the file types they represent.

If your file extensions are hidden see the March issue of The Printer for instructions related to making them visible.

This article has been provided to APCUG by the author solely for publication by APCUG member groups. All other uses require the permission of the author (see e-mail address above).



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Tulsa Computer Society 07/01/2007
Don Singleton, President