DAT file extension could represent following file types:

- Data file

- A data file extension used to designate an error message in a inbound internet email message (Microsoft Exchange Server v 5.0)

- WordPerfect Merge Data

- Extension used for some MPEG files

- Yahoo Messenger archive file

PSD is a file extension used by Adobe Photoshop to store its graphics files. Adobe Photoshop is a de-facto standard in a raster image editing software. First version of Photoshop was developed in 1988 by Thomas and John Knoll. It was subsequently sold to Adobe Systems which owned it since then.

EML file extension is used to store email messages in RFC-8222 format. Many applications including Outlook Express, Thunderbird, Apple Mail, Windows Mail, Postbox, and others use EML format to export and import e-mails.

BIN file is short for binary file. It is impossible to open BIN files in text editor because they consist of information in binary form which could only be enterpreted by computer applications or operating system. This extension is also associated with extension used for UNIX executable files.

CDR is a file extension used by CorelDraw application. CorelDraw is a well-known vector editing software. Its initial version was released in January 1989 for Windows 2.0 and since then more than 20 versions of CorelDraw were released. At this time CorelDraw is available in desktop versions for Windows and Mac OS operating systems.

AI file extension is used by files produced by Adobe Illustrator. AI is a vector image format which means it stores graphics information as a set of geometrical figures with their coordinates, sizes and transformations.

Office Open XML (also referred to as OOXML or Open XML) is an ISO/IEC standardized ZIP-compatible file format originally developed by Microsoft for representing spreadsheets, charts, presentations and word processing documents. Starting with Microsoft Office 2007, the Office Open XML file formats (ECMA-376) have become the default file format of Microsoft Office.

You can open XLSX file using Microsoft Excel application. Microsoft Excel is similar to other spread sheet applications that can store information that can be edited and viewed on several platforms. You can run Microsoft Excel and open XLSX files on Mac and Windows through installed Microsoft Office applications.

SWF file extension is used to store Adobe Flash multimedia file format. SWF (pronounced “swiff”, short for “Shockwave Flash”) file format was developed by FutureWave Software Inc in 1995 and released as a storage format for FutureSplash Animator software on Windows and Mac OS.

File with DOWNLOAD file extension usually contains an incomplete download started by Apple Safari web browser. Apple Safari adds .DOWNLOAD file extension to a file name when it starts downloading. When downloading process is done .DOWNLOAD file extension removed from the file name.

Most frequent use of RAR extension is to store compressed information archived using RAR format. It is a proprietary compression format developed by Eugene Roshal. Compressing files is very useful when you want to transfer them over the internet since compression reduces amount of information to transfer. Also you may fit much more information on your PC hard drive if you compress information that you don't use.

In order to open CRDOWNLOAD file you need to know what exactly it contains. CRDOWNLOAD file extension means that the file download was started by Google Chrome but hasn't completed yet. Typically CRDOWNLOAD file extension is removed by Chrome once download is complete.

In computing, DLL (an abbreviation of 'Dynamic Linked Library') is a file extension for executable libraries. DLL files are commonly used by software programs to store parts of the executable code.