File Extensions: File Extensions are a convention used in minicomputer systems as well as many microcomputer operating systems. They consist of a suffix to file names that indicates the file type and is often used to determine file handling. In the case of the common PC operating systems (other than Unix) the extensions are usually three letter tags. Thousands of extensions have been defined. The following is a short list of a few of the most common.

Extension	File Type
.ARC	A compressed file in PKARC format
.BAT	An MSDOS batch (command) file
.BMP	A bitmap image file
.COM	An MSDOS executable program in a specific core image format
.DLL	A dynamic Link Library file
.DOC	Usually a Microsoft Word file
.DXF	Autocad file
.EPS	An Encapsulated Postscript (printer) file
.EXE	An executable program (several different formats)
.GIF	An image file format
.GZ	A Unix Compressed File
.HLP	A Microsoft Help file
.HTM	A Hypertext Markup language file
.HTT	A hypertext Template file
.ICO	An Icon file
.IDX	A Data Base Index File
.INF	A Script/Information file for Windows Setup
.INI	A file containing program initialization information
.JPG	A JPEG image file
.LZH	A compressed file
.MPG	An MPEG image file
.PCX	An image file
.PCL	A Hewlett Packard Print file
.PDF	An Adobe Acrobat Document file
.PIF	A Windows Program Interface File
.RTF	A Rich Text Format Text file
.SYS	An MSDOS executable program in a core image format used for device drivers.
.TIF	An image file
.TXT	An ASCII Text File
.WKx	Various spreadsheet files (WKS, WK1, etc)
.WPx	Various Word Perfect document files
.WMF	Windows Metafile
.WRI	A word processor file from WRITE (WIN3) or WORDPAD (WIN95)
.ZIP	A compressed file in PKZIP format

The following two sites are only two of the many file extension lists available on the World Wide Web:

• http://thereference.com/computer/filext.html
• http://en.wordpress.com/resch/exteng.htm"

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