How to: The how and whys of defragmentating a hard drive

Over a period of time you may save and delete hundreds of files and documents on your computers hard drive. These files are save, moved, deleted all over sections of the hard drive.

Whenever you delete a file and empty the trash bin, that cluster(smallest portion of disk space for writing files) of the hard drive is now empty and can be used for writing over again.


Now lets say you want to save a word document which is 900bytes in size. A gap/cluster size on the hard drive is usually 512bytes.

A portion of that word document, 388bytes, would have to be saved on another empty gap (cluster) somewhere else on the hard drive. Do this hundreds of times throughout the week and portions of files are spread all over the hard drive.

Defragmentation physically organizes the contents into the smallest number of contiguous regions (fragments). A defragmentation program moves files around within the free space available to undo fragmentation. This is a very intensive operation and cannot be performed on a file system with no free space. The default defragmenter which comes with Windows is okay, but there are faster and more efficient ones out there.


My preference is Auslogics, which is very fast and efficient and allows background programs running.