Understanding File Types in Windows

Successive versions of windows have reduced the amount of information displayed to the user. This is microsoft's attempt at making your PC easier to use, but for many it just makes things more confusing. You can reveal some of the most important hidden things and may well find it helpful.

Just a bit of history first so you can understand what you're about to reveal. Files used to be named according to the convention 8.3, that is 8 letters and a dot and 3 letters. Maybe

myletter.doc
somecalcs.xls
myhold.jpg

The first (up to) 8 are picked by the user to describe the file contents. The 3 are used by the operating system (eg, windows) to note what type of file it is. Some common file types are;

.doc	Microsoft Word File
.xls	Microsoft Excel File
.exe	Executable File - one that starts up a software application, for instance
.txt	A plain text file, can be read by Word, Notepad, Wordpad many others
.bmp	A full detail (ie large file size) picture
.jpg	A compressed (ie smaller file size) picture
.wav	A full detail (ie large file size) sound file
.mp3	A compressed (ie smaller file size) sound file

This was quite restrictive, with only 8 characters available to describe the file contents, and in windows 98 onwards you can use 256.

The software you use to view files is  - it can show all the folders and files on your hard disk. Don't confuse this with  which is for viewing web pages.

Depending how your start menu is set up, there are different ways to start up explorer. Maybe Start_My Computer, or Start_Programmes_Accessories. One way that should always work is to right-click on the start button and choose 'explore' from the menu. Like this;



Oh yes, before we go any further, set Explorer to View_Details, like this;



In Explorer, you need to press the little + button next to 'my computer' to reveal the list of hard drives and CD drives.



You can keep drilling down folders by clicking these + buttons til you get to a folder with individual files in it. It might look like this:



In there are two winamp media files, an excel file, a word file, an applications, two Micrografx Picture Objects. So where are those 3 digit file extensions? Windows is hiding them from you. Lets reveal them.

In explorer, choose tools then folder options, like this;



Now choose view and you see a list of settings. You'll see one that is 'hide extensions for know file types'. Uncheck that box, like this;



Now lets go back to the same folder and see how those files look now.



Now we can see that the file '01' is actually 01.wav' and the file 'ATrack01' is really 'ATrack01.mp3'.

Also, there are .bmp and .jpg files that are both described as being the same 'Type'. Why is this?

An Important Bit. Windows wants to associate every file type with a program - so that it knows what software to open if you click-click on that file. The 'File Type' in Explorer isn't really the file type at all, its the associated software. So if you have a graphics package installed and its associated with 6 different picture file formats, all of them will show as the same 'type' - even though that isn't really true. This is microsoft's way of making your computer easier to use, but in fact tends to cause considerable confusion.

Now take a look at this;



By changing the association of the picture files away from Micrografx, they are now reported as having a different type. In fact, nothing about the files themselves has changed.

How do file assocations get changed? Well, a few ways;

1. A lot of software is greedy, and when you install it, it will take file associations for itself. When this happens, file types appear to change. Some software even keeps taking associations back whenever other software trys to take them - OK if its the tool you want to use, horrible if its not.

2. Change it yourself in the software settings. Most software will have some settings, usually in Tools_Options or File_Preferences. You'll often find an associations section in there where you can choose what to set for that software.

3. In Explorer itself. Choose Tool_Folder Options and open the File Types tab. Here's the list of all file types your copy of Windows knows about, and the current associated software. If you choose a file type from the list, and press 'change' you can choose the software to be associated yourself. Now you're in control.


Broadband Internet Services