Troubleshooting Tools and Strategies

Disk Defragmenter is a Windows-based tool that rearranges files, folders, programs, and unused space on your computer's hard disk. This is occasionally necessary because of the way files are stored on disk.

When files are edited and outgrow their original space on the disk, the file is broken into fragments, with latter fragments stored in open spots elsewhere on disk. In addition, when files are deleted on FAT16 and FAT32 volumes, only the entries in the file allocation table itself are deleted. The formerly occupied space is marked as open and can be used by other files. When other files use the empty space, if it is not large enough to accommodate the remaining data of the file, the file is again broken up with the remainder stored in another open space on disk. This process occurs with every new and edited file that is stored to disk.

While this process makes storage faster and more efficient when the file is saved, it takes much longer to read and write fragmented files than unfragmented files. Creating new files and folders also takes longer because the space available on the volume is scattered. Windows must then save new files and folders to various locations on the volume. When many files on disk become badly fragmented, performance notably suffers.

Running Disk Defragmenter

Disk Defragmenter remedies this problem by rewriting the files on disk back into contiguous segments. To start Disk Defragmenter, from the Start menu, point to Programs , Accessories , and System Tools , and then click Disk Defragmenter .

You can analyze the volume to see how many fragmented files and folders there are and then decide whether or not to defragment the volume.

The amount of time that the defragmentation process takes to run depends on several factors, including the size of the volume, the number of files on the volume, the amount of fragmentation, and the available local system resources.

Disk Defragmenter defragments volumes formatted with FAT16, FAT32, and NTFS.

Disk Defragmenter Results

The Disk Defragmenter tool display is split into two main areas, as shown in Figure 31.1. The upper portion lists the volumes on the local computer. The lower portion shows how fragmented the volume is. The colors indicate the condition of the volume:

• Red areas show fragmented files.

• Blue areas show contiguous (unfragmented) files.

• White areas show free space on the volume.

• Green areas show system files, which cannot be moved by Disk Defragmenter. These system files are not part of the Windows operating system but include files belonging to NTFS (when applicable) and the system paging file.
  Figure 31.1 Disk Defragmenter

By comparing the Analysis Display band to the Defragmentation Display band, you can see the improvement in your volume after defragmenting. Always analyze volumes before defragmenting them. After the analysis is complete, a dialog box tells you if you need to defragment the volume.

You can defragment local file system volumes only, and you can only run one Disk Defragmenter console at a time. In addition, you must be logged on as an administrator or a member of the Administrators group. If your computer is connected to a network, network policy settings might also prevent you from completing this procedure.