Windows Vista: The Complete Reference (Complete Reference Series)
Windows stores information on your disks in sectors, which can be anywhere from 2 to 32 kilobytes (KB) in size . Files are stored in as many sectors as required to fit (for example, a 64 KB file would take two sectors on a disk with 32 KB sectors). These sectors do not need to remain sequential: Windows keeps track of which sectors are used for which files, no matter where they are on the disk. Sectors for a single file can be located just about anywhere on the disk.
Fragmentation occurs when you add and remove files from your computer. When you delete a file, Windows marks the sectors as available, and uses them the next time you create a file. If a file gets larger and contiguous space isn't available, Windows uses other available sectors to store the new part of the file. As you continue to use your computer, your files can become more and more fragmented. When you save a new file, if no contiguous space is large enough, Windows writes the new file using sectors that aren't together-the file is fragmented right from the start.
Fragmentation slows down your disk access and, subsequently, your computing efficiency, because Windows has to spend more time finding the parts of each file. The more chunks a file is split into, the slower Windows accesses the file, because the file system has to move all over the disk to find pieces of the file.
Fortunately, Windows comes with a program that moves the contents of files around on your hard disk so that each file is stored as one contiguous string of sectors-Disk Defragmenter. Run the Disk Defragmenter utility when you plan on not using your computer for some time, because it can take an hour or so, and has to restart if you change any files.
In this day of ultra -cheap, gargantuan drives (80 GB and beyond) with superfast access times (7200 RPM standard and 10,000 RPM becoming more common), fragmentation doesn't affect speed nearly as much as it did on older hard disks. One reason is that newer disks read an entire track (concentric circle of information) at a time from the disk into the disk's buffer memory, so it matters less if the sectors of the track contain information in the wrong order. If your disk has lots of free space, your files are less likely to be badly fragmented.
| Note | Even though Disk Defragmenter moves data about on your drive, no files or folders appear to move. How you organize your files and such is really an illusion anyway. Which folder you put your copy of the next Great American Novel in has nothing to do with where it's stored in the disk itself. |
Running Disk Defragmenter
Follow these steps to run Disk Defragmenter:
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Right-click the disk drive in the Computer window and choose Properties. In the Properties dialog box for the disk, click the Tools tab and click the Defragment Now button. You see the Disk Defragmenter window, shown in Figure 35-1.
Figure 35-1: Disk Defragmenter analyzing your disk for file fragmentation. -
Click Defragment Now. Disk Defragmenter starts to work and displays the results of its analysis.
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When Disk Defragmenter is done, a message asks whether you want to exit the program; click Yes.