Fragmentation, in common, means division into different parts. In computer's language fragmentation is a phenomena in which different parts of a file are stored in different parts of the hard disk. It happens normally when you delete or create a file or save changes to the file.
Suppose if you delete a file from the hard disk and then you saved another file to the hard disk greater then first file then the hard disk will store the part of that file equal to the deleted file in the space of the deleted file and the rest of the part will be stored in other part of the hard disk. Similarly if you store a file to the hard disk and then you make some changes to that file then there is a very good possibility that the changes may be stored in some other parts of the hard disk while the original file may be stored somewhere else.
This is not a very much serious problem for a user because the file system on the computer can work with a specific degree of fragmentation so, for most of the users it is not affecting the performance of their computer, that is why they do not need urgent defragmentation of their hard disk.
But it is mostly depending on the nature of work you are doing and the nature of your file and also on the nature of random-access disk mechanism, as all of these have a slight effect on the resulting performance. But normally, it is not considerable. But if you store a very large number of files and changes on your hard disk then it will surely affect the performance of the hard disk by slightly decreasing the performance of file system of the computer.
Due to this reason, a user, facing fragmentation in the hard disk, will need defragmentation of the hard disk. For this reason, disk defragmenter is used. For various windows various disk defragmenters are designed which work effectively for that specific windows. The use of disk defragmenter is very easy. You only need to right click the disk, in 'my computer', that is to be defragmented and then go to the properties. In the properties bar, you then have to click on the 'tools' tab. On that page, you have to click on 'Defragment now' option. Then click on the 'Defarment' button. This will start your defragmentation process in which different parts of your files will be re-united to form single files. It will improve the performance of your computer.
Disk defragmenter works as follows:
It first re-arranges the files the computer hard disk and then search for different parts of same file on the hard disk. It then re-unites these different parts of each fragmented file into a single file. this will help your computer to work more efficiently.
In modern versions of windows, Disk fragmenter run on a pre defined or may be user defined schedule. So, it runs automatically on that schedule and defragment the files on the hard disk. But it is not necessary to use that schedule because you have the options either to run the defragmenter manually or to define your own schedule for its working by making changes to the pre defined schedule.
So, it can easily be concluded that disk defragmenter is a good tool and it it facilitates a user by consolidating fragmented files on your hard disk.
This article is written by James Clark, who also writes for http://pckeeper.zeobit.com/, a site featuring lot of useful articles on registry cleaner, disk defragmenter, and disk cleaner.