Disk Defragmenter is a system utility provided by Windows for analyzing local logical drives, further locating and combining fragmented files and folders within blocks (clusters) of hard drive. You also can defrag logical drives from a command line using defrag command.

When we save a file it is divided in small stripes and saved on clusters, concerning the size of a cluster the number of fragments are created, for example to save a file of 16KB we need 4 clusters if the size of cluster to hold data is 4KB. Now it is not fixed that all these stripes would be saved in a contiguous fashion.

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Logical drives become fragmented as we create and delete files and folders or when we install new software, or download files from the Internet or from the local network. File system typically store files in the first contiguous free space that is large enough for the file. If a fairly large free space is not available the file system saves as much of the file as possible in the largest obtainable space and saves the left over data in the next obtainable free space, and so on.

As we know a file when saved either on FAT or NTFS file system, mostly files are never saved on a disk in a contiguous fashion. Gradually when the data increases along with the increase in the size of a file it becomes fragmented heavily.

The more fragmented the drive is, the slower the computer’s file the input/output performance will be eventually increasing seek time. Increased seek time causes delayed boot and overall slow performance of the system.

There are many third party applications which can perform the defrag option, but it is dangerous to use as their knowledge of the file system is questionable. A fault in a defrag operation could prove fatal and would cause permanent data loss.

I think we should rely only on Microsoft and Executive Software International developed “Disk defragmenter”.

There are several benefits of defragging a drive and we should make this as an important part of our computing. Defragging should be done at least once a month by any individual. Unfortunately, defragging the drive of local users in an enterprise network or a large network is not given priority. The only benefit we consider is the fast performance of drive, but it is not the case.

When a file is deleted the contents of files are intact and the only thing which gets deleted is the allocation information related to the file. Space where the deleted file is stored is marked as free space and becomes overwritten when there is a requirement of saving a new file. You must have noticed why it take to save a file and how a big file becomes deleted within few seconds? The reason is quite simple as explained above.

Files deleted from a defragged drive are easier to recover as compared to fragmented drive, any data recovery software recovering deleted files would be able to recover those files which are saved contiguously, and it is than we realize the benefits of defragging the drive. Please note that defragmenter is applicable to Windows operating system. Tools to run defrag on an other file system is a topic which I would be covering in next posts.

I think by this post in my best capacity I have made an effort for people to understand the importance of defrag.