When’s the last time you defragged your hard drive? What do you mean you don’t know what defragging is? You haven’t heard of the Disk Defragmenter utility?! Say it isn’t so! Just kidding. Most people probably haven’t heard of this tool, and if they have they probably don’t know what it does exactly. Let me fill you in either way.

When a hard drive gets filled for the first time, files are placed according to some algorithm that is probably based on a linear sequence to some extent (i.e. file B gets stored next to file A when A is the previously stored file). Once you have been using your computer for a while files will have been deleted, new files will be created on top of them, and eventually there will be gaps of free space on the hard drive that act as buffer space between files. These gaps will vary in size, but either way, they are a nuisance.

Imagine a full bookcase. You have lots of books of various sizes on each row. Then over time you remove some books and replace them, and as you do, you get different-sized gaps where new books can go. Sometimes, the gaps are really small and you can’t stick a new big book in any them. If you were to consolidate all of the gaps together, you would be able to provide enough space for that new big book.

The Disk Defragmenter shifts files around and consolidates extra space into contiguous chunks to allow for big files to get stored in one consecutive piece rather than being split up into many pieces to fit in the small gaps. Along with a bigger single block of free space being created, you are also increasing the speed of your computer by making it so files are not divided into different parts of the hard drive. Remember, a hard drive is a magnetic disk with a needle that reads data from the surface while the disk is spun rapidly to the start point of a given file. If the file is stored in sequential blocks on the hard drive, then it’s just a matter of jumping from block X to block Y (which is as fast as you can get). Otherwise, the disk might have to be spun to block X, then block R, then block B, then block S to get the full contents of a file. That would take a lot longer than it needs to.