Project X1 for CNIT 121: Identifying File Types (Up to 25 points)


To practice identifying unknown file types.

Getting the Files

Download this 7-zip archive:
Open it with 7-zip. If you don't have 7-zip, you can get it here:
When the files are extracted, you should see a folder with six files, like this:


Your goal is to determine the correct file type and therefore the correct file extension for each file. Right now they all have .TXT extensions, but none of them are actually TXT files.


You can do it any way you like. The technique I demonstrated in class was to use Notepad in Windows.

The first file is the one I used for a demonstration in class, so it's not worth any points.

Here's how to solve the first one.

Double-click file1.txt to open it in Notepad.

Although most of the file is unreadable binary, the first few characters are readable ASCII: GIF89a

You may remember from lecture that this is a GIF file. If you don't remember, just Google "GIF89a" and you will find that the correct file extension is .GIF

To test your solution, rename the file to the new extension, as shown below:

Then double-click the file to open it in a program appropriate to its real type:

As you can see, the file is a recognizable image of a penguin. It opened in Internet Explorer on my system.

When you get the extension correct, each of these files will open to create a recognizable, useful document.

Use the same procedure to find each extension, as summarized below:

Turning in Your Project

There are no images to capture. Just send an email to with a subject line of "Proj X1 from YOUR NAME".

In the body of the email, give the correct filename extensions for each file like this (using the correct extensions, not TXT)

File2 TXT
File3 TXT
File4 TXT
File5 TXT
File6 TXT
You'll get 5 points for each correct answer.

Last modified: 1-18-13