The File Allocation Table is the keystone of DOS or the Disk Operating System, the basic operating system that PCs have used for many years. While DOS handles other tasks, such as orchestrating printers, keyboards, and monitors, the bulk of the effort is managing how a single file is stored (and sometimes scattered) on the magnetic bits of a floppy or hard drive. This same concept is still in use in modern file systems, which organize the manner in which bits are stored on disk.
An analogy of FAT can be found in a library that uses a card system to look for a book.
You can search by book title and the card will tell you where in the library to look for the book. Take the concept further by visualizing a book is still in the library, however the different chapters are scattered through different parts of the library.
The index card would tell you that 1) the book is there, and 2) where you would find the different chapters or even pages of chapters in the library. This is how FAT works.
If you delete a book from the library because the book was out dated, you could insert a new book in whatever spaces were available in the library. Over time, your library would become quite scattered and it would take a bit of time to get the data together on one entire book. In a computer file system, this is known as fragmentation, and it slows down the computer much like youd be slowed down getting a book in the far corner of your library.
This program is also known as disk defragmenter. In geek shortspeak we refer to this as Defragging or Defrag. Microsoft includes a defrag utility in Microsoft Windows. Other software vendors also sell enhanced defrag utilities, which do a more thorough job or perhaps have more features (bells and whistles) in the program. For most users, though, the Windows defrag program is all that you need.
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