Originally Posted by cat_sorcerer
What is the purpose of defragging??
Defragging re-consolidates files stored on a hard drive. Quite frequently, on a Windows PC, as files are written to the hard drive, they are split up to fill in empty or blank spaces on the hard drive. The operating system has to manage (keep track of) where each piece of each file is located in the File Allocation Table. So, for example, if you have 10 files on your computer and each file is split into 10 pieces to fill in empty space, your File Allocation Table has to keep track of the 10 original files and the 100 pieces to make sure you have access to the files. Now expand that thought to thousands of files and the FAT has to keep track of hundreds of thousands of file bits. When you defrag, the system moves pieces of files around so that each file is written to a contiguous portion of the hard drive. This means that the operating system only has to keep track of the file in one spot. As you use the computer, this splitting of files happens more frequently and therefore the system begins to slow a bit. With normal fragmentation of the hard drive, the normal user should never see a difference in system performance, but as fragmentation gets higher and higher(as time goes on) the system can slow down drastically.
Hope this helps a bit.