1. What Is a File? A file is a collection of binary symbols stored in specific locations on a drive and referred to by a unique name. For example, a file can be a letter created by MS Word, a picture created by Paint, an accounting report created by Excel, or the sounds of a musical composition. Each of these is represented in a different file format.

2. What Is a Format? All computer data are in one of two states - binary. Memory - tiny electric currents, High/Low or On/Off Hard disk - magnetic blips, Present/Absent CD or DVD – laser burned pits, Present/Absent We could call these states Jim/John, Apple/Orange, Table/Chair. It works best to call them 0/1. Suppose you want to represent a letter, a color, a sound in the computer. You need to define a convention for what sequence of 0/1s is the letter G, what is red, how to represent the note of middle C, etc. For example, G is usually 01000111. These conventions are called formats.

3. How Files Are Created Every file has been created by an application Hard Disk Hard Disk or other Memory An applicationIn memoryThe application such asthe programassigns a unique Word, Paint,generates thename to what it program compiler content of thecreated and saves etc., is loaded intofile to be saved,it on a drive, the memoryletter, picturehard disk, flash program, etc.drive, CD, etc. Each application uses its own special formats for the kind of files it produces

4. Formats and File Extensions The file extension tells Windows what the file format is and which application to use with the file. Examples:.DOC,.DOCX - MS Word, Open Office app.XLS,.XLSX- Excel, Open Office app.PPT, PPTX- PowerPoint, Open Office app.JPG- Paint, Internet Explorer.MP3,.WAV- Windows Media Player In the Windows Control Panel you can change which applications handle which file extensions.

5. How Files Are Saved The application that created the file asks you to: Assign a name to the file Decide where the file should be saved It may give you a choice of several formats to use Windows then saves it as you specified. The application assigns a file extension depending on the format the file is in. The next time you use the file that file extension tells Windows which application should handle it.

6. How Files Are Named Every file has a unique File Name A file is named when first saved. Windows keeps a record of where files are located in the File Allocation Table. Recorded there is the file’s location, its size in bytes, the date and time when it was created and various file attributes. File names may contain alphabetic characters, numerals or some special characters such as a hyphen, parenthesis, blank (space), ampersand (&), underscore (_), or tilde(~). You cannot use / \ | ; : + =. If you use an illegal character, a pop up will notify you of the error.

7. Where Files Are Located Every saved file is in some folder on some drive Information in computer memory is lost when power is turned off. To retain it, data are stored on drives, in folders, as named files. Drive: A physical device for storing persistent information, either in the computer of attachable to it. In Windows a single capital letter followed by a colon denotes a drive. C: is usually the hard drive. Folder: An addressing convention used to organize files on a drive. The physical location of a file on a drive is not determined by the folder it is in. Files on a drive not located in other folders are said to be in the Root Directory or Folder. Additional folders are created in the Root to keep related files together and to protect them from being mistaken for other files or accidentally deleted. You can create folders within other folders.

8. How Files Are Recovered Windows uses the file’s extension to bring the matching application and the file into memory. The file can then be processed – viewed, edited, saved elsewhere, etc. by the application. Application and file both in memory Windows locates application using file extension Locates file using file name