Defrgamentation for your hard drive

First here is some background about the file systems, then I'll explain the actual need of defragmenting.

What is a file system?
When files are stored in the computer, the operating system or OS(Unix, MacOs, Windows...) must have a simple way of sorting them. So when we need to access a file the OS must know where to find it or its exact place. Moreover the OS also needs: its occupation on the disk, size, name, creation date(properties and attributes). Many ways exists this arrangement to be accomplished and that just is the primary role of the filesystems. They are also responsible for allocating free space over the disk media, arrangement, indexing and more. For example Windows uses the following file systems: FAT16 FAT32 and NTFS.

File system problems
Together with the previous ones the operating system solves many other important issues. For example when we save file on the harddrive it is stored continuously (without breaks in the drive's space). Next to the first a 2nd, 3rd one and so on files are stored. But when а file is deleted its place becomes a gap, having length(size) exactly like the erased size. When later the continuous free space finishes the filesystem uses the open gap where places another file. But as we know files have different size.
For example if there is 40kb. left from previously deleted file and we save a new one with size of 30kb. then the last 10kb from the freespace will be free(gap). For that reason the filesystem maps the drive. The map describes how much freespace is left and its location on the drive.

Need of defragmentation?
Let's suppose that we have a 10kb. freespace from an previously erased file, and a 90kb freespace on the end of harddrive. We want to store a new 100kb. file on that drive.
We have that 100kb. space, but it is not continuous - it is in the form of two small parts: 90kb. at the end and 10kb. left from the erased file. How this could be done?

Solution to the problem
To accomplish the above task the filesystem takes the file apart into several pieces and saves the first part(10kb. in that case) in the first found freespace. The lasting 90kb. are placed on the freespace left at the end of the drive. This process of separating the files in small parts or fragments is called fragmentation. This way the more separations or fragments exists the more the loading of 1file is prolonged. The usual software uses 10-100 or even 1000 files. Imagine this way how much the loading could be prolonged. For that reason it is good once in a month an arranging of the files to be done(defragmentation). This way you'll increase the performance of the computer. Usually this procedure takes time:

In order your defragmentation to be faster follow these simple steps:

1. Stop your antivirus/antispyware programs.

2. Do not use the computer in the time of defragmenting.

3. Ensure that there is a lot of free space (>20%) on your harddrive.