DAT – it is used by Windows Operating System to store application “data”. It can store images, binary data, 3d graphics and any other kind of information.
PPS – it comes from Power Point Slide Show and it’s a data type file that can incorporate a mixture of text, pictures and even movies. These files can also include information on how the presentation is displayed, such as the transition effects between slides.
TORRENT – it is used to store information produced by BitTorrent clients. These type of files, most of the times, contain metadata information about files that you intend to share and about the computer that coordinates data distribution.
Note: BitTorrent is often used to share copyrighted information so they should be treated with care.
DLL – it’s the short version from Dynamic Link Library. The DLL files were introduced because not all executable codes could fit in a single “.exe” file and some codes needed to be shared between applications. They also contain helper systems used by applications for certain features.
EXE – this extension stands for EXEcutable. What it does is, when you choose an application and try to start it, Windows searches for an “.exe” file associated with this application and starts executing it.
XLS – it comes from Excel Spreadsheet and it’s created by Microsoft Excel application. This is the most popular computer application until now and is a part of Microsoft Office Suite of applications.
DOC – file extension DOC stands for DOCument and it is created using Microsoft Word for Windows applications.
The newer versions of Microsoft Word use the DOCX file extension, which is an extension of DOC file format. The biggest advantage of this new format is that it can be opened and read by other applications, not just Microsoft Word.
PDF – it represents a general file format created by Adobe Corporation. These days, a big part of the documents transferred via internet, are stored in this format.