4. Why are different file types needed?

1. So that you know the correct software to use

If you see the file extension .ppt, then you would probably know that you need to have access to PowerPoint presentation software, if you see a file has a .mdb extension and you know you don't have Microsoft Access installed, you would quickly realise that you cannot open the file.

2. So that the user knows what the file may contain from the file extension

If you see a file with a .swf extension, you know that the file is likely to contain a multimedia video. If the file extension is .mp3 then you would know that it is likely to be a music file.

3. So that searching and sorting files can be done effectively

If you have different file extensions, it makes it much easier for you to search for a specific file type. For example, if you know you are looking for an essay but you can't remember where you stored it, you could search for all of the .doc files on your system.

4. So that the operating system can display appropriate icon

When you look at the details of the files on your system, you will often see a small icon next to the details which indicates the specific file type. For example, you might see a small blue W icon next to all of the Word document files and a small green X icon next to all the Excel files.

5. So that it is easier to open the appropriate application

Double clicking on the data file will normally load up and run the appropriate application for that specific file type.

6. So that application programs know how to load up and interpret the data

If you open an Excel file by double clicking on the icon or file name, when the application opens, it will know how to load and interpret the data held in that file.