Open EPUB File

What Are File Extensions? - Part 2

Given the example, we can now ask how important are file extensions? In reality, file extensions are part of a computer's filesystem or the format of organizing files on a particular computer. This is often affected by the type of operating system installed. File extensions point back to the original application that created them or simply markers of the application. These markers allow us and the computer to determine what type of applications can open these files.

File extensions are often suffixes of the applications that created them. Programs written in Visual Basic Script (VBScript) will have file names ending with the *.VBS extension. But not all are derived from their respective applications. Commonly used extensions may contain two to four letters. Microsoft's PreFetch files have *.pf extensions, Microsoft Word documents have *.doc, and static web pages written in most WYSIWYG's have *.html extensions. File extensions are appended after the dot (.) sign which also follows the written filename. In most cases, we do not choose the file extension. Applications automatically add it to the filename, but we can change it and affect the content of the file.

File extensions allow computers to process files effectively and accurately. Instead of taking more resources of a system in looking for applications to render a file, it automatically locates and connects to the application that can open the file. This reduces the time used by the computer in opening a file. There are computers systems especially UNIX where the use of file extension is optional, but not Windows. For Windows to open a file, it must be associated with a file extension.

Continue reading: third part of the "What Are File Extensions?" article