Defragmenting a hard drive

What does defragmenting a hard drive do?

Imagine that your hard drive is a 25-page spiral notebook. Initially it is completely blank, so when you first start writing in it you start at page one. After a while, you have one entry that is 5 pages, one that is 3 pages, and one that is 15 pages long. Then you decide to erase the middle entry, which leaves you with 3 empty pages in the middle of the book, and 2 at the end. So what happens if you write an entry that's four pages? The only way to do it is to put the first 3 pages in the middle of the book and the last page at the end, and remember that it's in two places. Since you now have to go to more than one place to read your entry, it takes longer to do so.

Hard drives do basically the same thing. At the beginning of the hard drive, there's a small area called either the Master File Table (MFT) or File Allocation Table (FAT) that records where on the hard drive files are actually stored. Then when you want to access a file, this table figures out the location of all the bits and reads them. If the majority of your files are scattered in this way, your computer will likely run quite slowly.

This is where disk defragmenting comes into play. When you run a defragmenter, it moves all the files around so all the bits are right next to each other. Using the example above, it would rip out the last entry in your notebook and move it to the end, so your 4-page entry will be continuous.

How do I defragment my disk ...

...under Windows XP or Windows 2000?

1. Go to Start > All Programs > Accessories > System Tools > Disk Defragmenter. (Phew! That's one buried program!)
   
   
   
2. Now, select the drive you wish to defragment and click Defragment. If you have multiple hard drives or partitions, you'll have to do them individually.
   
   This can take some time. If it does not solve your problem, please read the FAQ further or feel free to contact us at x18062.

... under Windows Vista?