First let me explain what a file extension is used for, then I’ll go on to explain how to fix problems with unrecognized file types

Each application program stores its data in some format, which may or may not be recognized by other application programs. This data storage to a permanent or temporary storage medium is in a specific format that the concerned application program can understand and process.

To distinguish among the different file formats out there, we use the file extensions.

The file extensions are like signature to an application program, as only one application can open and process a particular file extension in a system (and the application programs register their native file extensions when they are installed in the system). This is usually a three or four letter alphanumeric code added at the end of the name of a file.

For instance: battle.doc, surgery.ppt, status.mpeg, etc.

The file types and the extensions present in a system are usually dependant on the number and variety of the software installed. Usually one file with a particular extension cannot be opened by a different application. And in Windows based systems, the file extensions are hidden from the users by default. But you can view them by doing a small tweak in Folder Options, View tab.

Two types of files are data files and program files. The data files are used to store data, whereas the program files manipulate the data. Examples of data file extensions are .doc, .xls, etc., and the examples of program file extensions include .exe, .dll etc.

Usually one particular file extension may be used by more than one application program. Therefore, it may have different format descriptions, program ID, and general data structure dependant on the particular application that creates it.

Some other properties of the File extensions are these (all these properties are dependant on the application that creates the file, and vary according to that). :

1. MIME type: Multipurpose Internet Mail Extension (MIME) type is used to describe the encoding of the file when it is sent across the Internet through email documents, usually as an attachment.
2. The identifying characters: These characters come at the beginning of the file with the particular extension. Usually these characters identify unique attributes about the particular file.
3. Program ID: The Windows systems use a single most important database of everything that is run, stored, or processed in the system, called the registry. The application program that uses a particular file extension is identified in the registry through its program ID. This may be ASCII or Hexadecimal. Also this is specific to the particular application that creates the file.

Some of the major file extensions are these:

• XLS: Microsoft Excel Spreadsheet
• PPS: PowerPoint Show
• DAT: Generic Data file
• BUP: DVD IFO Backup file
• ODT: OpenDocument Text file
• DB: File used by Paradox Database and many other RDBMS applications.
• WMV: Windows Media Video
• M4V: MPEG 4 Video part 14
• OFX: Either Olicom Fax file or Open Financial Exchange file
• ASPX: ASP-XHTML (also ASP-XML) file (Active Server Pages-Extensible HTML) XML-Extensible Markup Language
• DLL: Dynamic Link Library
• BIN: Binary file
• PDF: Portable Document Format

The file extensions are usually widely accepted for many of the most popular files. But some of the file extensions are still very widely used by different applications for different types of data. A standardization in this is highly appreciable and desirable.

constant-content.com | March 20th, 2008
Tags: file extension
Categories: File Extensions

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