Files
Computers organize data in groups according to their purpose. We call these "files." You will already know about many kinds of files, such as JPG, GIF, and MP3 files. These are used to store images and sound. But your operating system, documents, settings, and every other function your computer performs is also stored in files. A file is really just a long string of numbers stored by the computer, with a set structure to allow the computer to determine what kind of information is inside. Many file types Many file types include "metadata," which is information about what's inside the file. Most files will have a section at the beginning, called a "header," which contains information about what type of file it is, it's length, the date it was created, and other information the computer may need to use it.
This data is usually visualized in hexadecimal, and can be view using special software called a "hex editor." It's usually not important to look inside files at this level, but it is important to understand what files are and to be able to identify some key file types. You should recognize the following file types.
Text files:
TXT, DOC
Image files:
JPG - pronounced "jay-peg," a very common image file
PNG - almost as common as JPG, can have transparent backgrounds
GIF - useful mostly because they can be animated
Sound files:
mp3 - a very common file type
MP4 - newer and more efficient (smaller) than mp3, can also be used for movie files
WAV - an older and larger format, often used when recording sound
Others:
PDF - a file format that provides a lot of information so that it will look the same on many different kinds of device
Zip - a file that has been compressed (made smaller), can contain many other files within it, must be de-compressed before use
