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.

File Extension Problem?

Can’t Open a File or Program? Unknown File type Error?

Most computer users will be familiar with using files, however not all users will be aware of file extensions or what they mean.

File extensions are the suffix after the file name that lets you know what type of file it is. File extensions usually have three or sometimes four letters, preceded by a period and occasionally may even incorporate numbers.

An example of a file is mywork.doc – in this case mywork is the file name or root name and doc is the file extension, which tells you it is a Microsoft Word document.

Your PC needs to know the file extension so it can use the correct program to open the file. Occasionally you may see a message telling you your operating system does not know which program to use and asking you to select one to open the file. When this happens, it helps to know a little about what each file extension means and which application is needed to work with the file.

Below is a list of some common file extensions and the type of file they represent.
* xls – a spreadsheet created by Microsoft Excel
* pps – a Microsoft Power Point slide show
* dat – a data file
* bup – a backup file for a DVD IFO file
* odt – Open Office or Open Document text document
* db – a database file
* wmv – a Windows Media video file
* m4v – an iTunes video file
* ofx – Open Financial Exchange file
* aspx – ActiveX server pages of Microsoft.Net
* dll – Dynamic Link Library
* bin – a binary file or a CD image file
* pdf – portable document format created by Acrobat Reader from Adobe

Each application on your PC will have its own type of file extension. Whenever you work with or save data, you will be able to see which type of file extension is used by that particular program.
When you explore files stored on your computer, the file extension is usually hidden. This is a default setting on Windows. It is possible however to change this setting by going to the Control Panel and selecting Folder Options. Click on View and in the list that appears, locate ‘Hide file extensions for known file types’ and uncheck the box. The extensions will now be visible.

Some file types can be dangerous and may harm your PC by executing a virus or malicious script. Be particularly careful when opening email attachments and if you’re at all unsure of what they contain or if you don’t know the sender, it’s best not to open them at all, or if you must then check them first using your anti virus scanner.

There are many hundreds of file extensions in use today and although it would be impossible to learn what they all mean, it’s a good idea to get familiar with the most common types at least. Not only will it make your computing experience easier but can also keep your PC safe from harm.

Download this free scanner and find out just how clogged your Windows registry really is.

File Extension PPS:

PPS files are associated with the PowerPoint Show Format

PowerPoint Show format (PPS) is a presentation document format, used to create a PowerPoint presentations. PowerPoint, supplied by Microsoft, is a presentation program. PowerPoint is also part of the Microsoft Office Suite. As in the case of other software in the Office Suite, PowerPoint is supplied for Windows and Mac OS. It has reached its latest version, MS Office PowerPoint 2007. Today the PowerPoint is the most important and most popular format recognized for presentation purposes. Many major companies, corporations, etc., use PowerPoint as their presentation software.

The PowerPoint presentation is created in pages called slides, which can contain other objects like text, graphics, or even documents in other formats (even independent formats) using Microsoft’s OLE technology.

The PowerPoint was previously a copyrighted product of a software company, Forethought. Microsoft purchased the product and license for $14 million from them, and developed it as their own.

The PowerPoint documents support graphics, animation, slideshow, and text. The PowerPoint Viewer can be used to view the finished PowerPoint presentations. The extension PPT (PowerPoint Template) is an editable presentation file, whereas PPS is for only the show. PPS can also be edited using the PowerPoint application, however, it is optimized for the viewing. So, the PPS files will be less size than the corresponding PPT file.

Attributes of the PPS File Extension:

1. MIME Type: Multipurpose Internet Mail Extension (used to recognize the format when sent across as attachment in an email).

application/vnd.ms-powerpoint

2. Program ID: Used to identify uniquely, the program for the file extension within the Windows Registry, which is a database of all data and applications in the system.

PowerPoint.SlideShow.8
PowerPointViewer.SlideShow.11
soffice6.pps

Properties of the Presentations:

PowerPoint Presentations support Microsoft OLE technology, as do the other applications out there. They can hence include any type of object within their body. Also, the VBA (Visual Basic for Applications) will help make the presentations have the ability to process data, and behave almost like application programs. VBA comes packaged with higher versions of MS Office Suite. There are templates provided by Microsoft supplied with the application, which can be used to create slides. The templates can define the placement of text and other objects. Some templates even give the power of adding statistical diagrams like pyramid, bar graph, Venn diagram, and many others.

The animations supplied by the PowerPoint are of two types: slide animations and transitional animations. There are subtle, moderate, and exciting animations available preset in the application. Besides this, the custom animations can be done for the entry, emphasis, and exit of the objects in a slide. We can also animate the text’s movement. Custom animation can be created by choosing Slideshow from the menu and choosing Custom animation. The animation can be applied to all slides or select few. The transitional animations help decide how the transition from one slide to the next is done.

Besides these, there are many other features supported in PowerPoint presentations. The PowerPoint presentation format, as it has almost become the standard format for presentation, is recognized by also the other platforms like the Mac software, OpenOffice.org software etc.

Today’s PowerPoint Show is an XML based open format. It is downloadable from the Internet from Microsoft website. XML, the Extensible Markup Language is tomorrow’s format description scheme. It can well enhance the reach and popularity of the PPS documents.

A file extension is a string of characters preceded by a dot (.) and appended to the end of a computer filename.  It usually consists of three (or sometimes four) characters, whose purpose is to identify the file type.  Some examples of common three-letter file extensions are “DOC,” which represents a Microsoft Word document file and “EXE,” which represents an executable file—a computer program that performs (or executes) a specific action (or actions) when opened.  An example of a four-letter file extension is “JPEG,” which represents a compressed image file.

The following examples illustrate the format generally used for filenames and extensions:

Filename.doc
Busyfile.exe
Photo.jpeg

In the hypothetical filenames above, the portion before the period (or dot, as it’s more commonly known) represents the file’s root name.  The extension is added partly to allow computer files to be more conveniently categorized and organized into groups of similar files, which then become easier to locate and access.  It can also indicate which computer program is required to open the file.

In theory, at least, filenames also allow the computer user to distinguish between harmless, helpful files and malicious files, which can contain viruses and other types of malicious software.  While depending on file extensions to protect a computer from malware isn’t always completely effective, file extensions can often provide clues that something is amiss with a particular file.

For example, simply knowing that a file is an executable file (by the fact that it contains the “EXE” extension) can often help us avoid inadvertently downloading malicious software.  If the file we’re interested in downloading presents itself as an informational text file of one sort or another and yet contains the “EXE” extension, that should tell us that downloading that file will execute some type of action which will affect our computer in some way.  (And the underhanded nature of the offer should warn us that the action will likely be harmful.) 

Again, should we receive an e-mail from an unknown source offering information through a link to a website, and that link contains the “EXE” extension, we can be sure that the individual who sent the e-mail intends to download a file which will execute some sort of action on our hard drive—very likely a devious one.  (We can check the actual file extension, even if it’s been disguised by the link’s anchor text, by lightly passing the mouse over the anchor text, without clicking, and checking the real website URL and filename in the status bar at the bottom of our screen.)

While there are ways for computer hackers to disguise file extensions to prevent the recipient from recognizing and becoming suspicious of executable files, whenever we do see the “EXE” file extension, this should be our cue to be very cautious and not to click the link unless we know and trust its source.

Sometimes, files which contain the “DOC” extension are actually malicious files masquerading as Microsoft Word files.  If your computer is set to display file extensions, however, you’ll be able to quickly see whether or not an extra extension has been added to the filename after the “DOC” (or other initial) extension, which would signal a file type other than the one indicated by the original extension.  (The last extension following the final dot in the filename—when there’s more than one—is the extension that indicates the file’s actual type.)

File extensions can tell us a great deal about a computer file—particularly if we exercise both care and vigilance in evaluating them.

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The Portable Document Format (PDF)

Portable Document Format (PDF) is a file format created by Adobe Systems Inc., and supported in Adobe Acrobat, Adobe reader, and many other third-party PDF reading and processing software.

The PDF is a text based document format, which grew up to include any type of multimedia. The primary aim of PDF is to render files like articles, e-books, etc., as a printable document. Other document formats like HTML may not be quite friendly with printers. Therefore, their outputs usually go askew when printed. The PDF documents are created by digital printing (usually from documents in another format). It is not an easily editable format.

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