About Filename Extensions

Some operating-system use filename additions to recognize different kinds of information.  For example, a computer file known as papers.htm or papers.html is noticeable as a Web page.  A computer file known as papers.gif is noticeable as a particular type of picture computer file, while papers.jpg indicates an picture computer file of another format.  A Ms Word papers might be known as papers.doc, whereas a plain written text computer file would most likely be known as something like papers.txt. Web servers, which may run on a number of different operating-system, use filename additions to recognize computer file kinds. The Ms Disk Managing System (MS-DOS) uses filename additions.  Ms windows uses them too, since it is built "on top of" MS-DOS.  Ms windows is often configured to hide filename additions, so that you may not be conscious of them.  (But see below for the remedy.) The Mac OS doesn't use filename additions.  A very different system is employed to recognize different computer file kinds, so that a computer file known as papers could be almost anything -- written text, graphics, audio, video, whatever.  Mac customers who want to publish on the Web or share information with Ms windows customers need to be conscious of filename additions and start using them correctly.