Windows XP Home Edition: The Missing Manual

Disk Defragmenter

As you create files using your various programs, Windows lays them end-to-end on the hard drive surface. Later, when you type more data into a document (thus enlarging it), the file no longer fits in the same space. Windows XP puts as much of the file in the original location as can fit, but may have to store a piece of it in the next empty spot on the hard drive.

Ordinarily, you’ll never even notice that your files are getting chopped up in this way, since they open promptly and seamlessly. Windows keeps track of where it has stored the various pieces, and reconstitutes them when necessary.

Eventually, as your drive fills up, even new files may not fit in a single “parking place” on the hard drive surface, since there are no free spaces left that can hold it. In fact, Windows may have to store a file in five, six, or even more pieces. If your hard drive remains mostly full for a long time, this file fragmentation may result in noticeable slowdowns when you open or save files.

The solution: Disk Defragmenter, a program that puts together pieces of files that have become fragmented (split into pieces) on your drive. Although Disk Defragmenter takes some time to function, a freshly “defragged” PC feels faster and more responsive than a heavily fragmented one.

Tip

Fragmentation doesn’t become noticeable except on hard drives that have been very full for quite a while. Don’t bother defragmenting your drive unless you’ve actually noticed it slowing down; the time you’ll ...