What Files Are

Files are a collection of data onto a permanent storage structure. They are stored on a permanent storage media such as a computer hard drive, CD ROM drive, floppy disk drive or sometimes even a tape drive. Files take a certain amount of room to store. For example if you have two text files and one file has one sentence in it while the other file has 200 sentences in it, the file with 200 sentences will use more room on the storage media.

File Functions

Different files have different purposes. Files are used to do one or more of the following functions:

• Provide machine executable code which is used to run application programs and the operating system.
• Store application program or operating system configuration information.
• Store data used by the user such as Microsoft Word document files.

Therefore there are three types of information that files contain:

• Executable code.
• System or program configuration information.
• User data.

These files are read by an application program or the operating system.

File Characteristics

Files have the below characteristics:

• Name
• Optional extension name - Part of the name, it is used by Windows operating systems to identify an associated program that can be used to read it
• Size - Shows the space the file requires for storage normally showed in kilobytes (Kb) which is 1000 bytes
• Type - Indicates the program used to access the file. The next section will talk more about file types.
• Date Modified - Shows the last date the file was created or changed.
• File structure - This characteristic is not viewable by the computer user but some programs can examine file structure to determine the type of file it is even when the file extension is changed.

The main items to remember include the facts that all files take a certain amount of room on their storage media and all files have a type which indicates whether they can be run by your computer. The file extension is one indication of the file type but not the only way to determine type.

If you are browsing your files using "My Computer" and click on "View" and "Details" you will see a window showing the file characteristics like the one below. Folders only take a little room on the hard drive and do not normally take as much room as files.