Introduction to Disk Defragmentation As advanced as hard drives have become, one item they are not very good at is housekeeping, or maybe that should be drive keeping. When files are created, deleted, or modified it's almost a certainty they will become fragmented. Fragmented simply means the file is not stored in one place in its entirety, or what computer folks like to call a contiguous location. Different parts of the file are scattered across the hard disk in noncontiguous pieces. The more fragmented files there are on a drive, the more performance and reliability suffer as the drive heads have to search for all the pieces in different locations. The Disk Defragmenter Utility is designed to reorganize noncontiguous files into contiguous files and optimize their placement on the hard drive for increased reliability and performance. Why Defrag Disk? Fragmentation is caused by creating and deleting files and folders, installing new software, and downloading files from the Internet. Computers do not necessarily save an entire file or folder in a single space on a disk; they're saved in the first available space. After a large portion of a disk has been used, most of the subsequent files and folders are saved in pieces across the volume. When you delete files or folders, the empty spaces left behind are filled in randomly as you store new ones. This is how fragmentation occurs. The more fragmented the volume is, the slower the computer's file input and output performance will be. Defragmentation is the process of rewriting non-contiguous parts of a file to contiguous sectors on a disk for the purpose of increasing data access and retrieval speeds. Because FAT and NTFS disks can deteriorate and become badly fragmented over time, defragmentation is vital for optimal system performance. Using Disk Defrag on Windows XP Accessing Disk Defragmenter • Start | All Programs | Accessories | System Tools | Disk Defragmenter • Start | Run | and type dfrg.msc in the Open line. Click OK • Start | Administrative Tools | Computer Management. Expand Storage and select Disk Defragmenter The first two methods take you to a standalone window containing Disk Defragmenter. The last method opens Microsoft Management Console and displays Disk Defragmenter as one of the snap-in modules. In all cases, a window similar to the one below will be displayed.; When Disk Defragmenter first opens (Fig. 01) you'll see a list of the hard drives displayed at the top of the screen. The Estimated Disk Usage Before Defragmentation and Estimated Disk Usage After Defragmentation will be blank until a drive is selected and the Analyze button is clicked. In the screen shot above, I've already analyzed the drives as evidenced by the Session Status showing as Analyzed and the Estimated Disk Usage Before Defragmentation area containing a graphical representation of the drive fragmentation. After the Analyze button has been clicked and the process completes the window shown above (Fig. 02) opens with a brief recommendation of what action Disk Defragmenter thinks should be taken regarding the drive. It's important to note that this is just a recommendation based on the percentage of fragmented files to total files and doesn't prevent the drive from being defragmented if you feel it needs to be done and might improve system performance. If you want to go ahead and defragment without more information, click the Defragment button. If you're in agreement with their recommendation and don't want to defragment, click the Close button. Click the View Report button to view a more detailed drive analysis. An Analysis Report contains quite a bit of additional information about the selected drive. The report shown above (Fig. 03) details the File Fragmentation status of drive New Volume (D:). The top pane provides Volume information, and as you can see there are 3,851 fragmented files. This may not seem like many fragmented files, but consider that this is only a 29GB drive, which is very small by today's standards, and that 97% of the total drive space is currently unused. Look at the Average Fragments Per File number of 1.04 and this tells you that approximately 4% of the files on the drive are in two or more pieces. My experience has been that when this number reaches 1.05 the message in the quick analysis window (Fig. 02) will recommend defragmenting the drive. The bottom pane, Most Fragmented Files, lists the files in descending order that are the most fragmented. Click on Defragment button to Defrag the drive. You can see the status of Defragmentation in the status bar. Disk defragmentation is now complete, click on View Report button to view the Defragmentation Report. In spite of the recommendation not to defragment this particular disk, I went ahead and clicked the Defragment button. The results of that choice are shown above (Fig. 04) in the Estimated Disk Usage After Defragmentation section. The graphical representation clearly shows that not only have the red lines depicting fragmented files been eliminated, many of the contiguous files indicated by the blue have been repositioned toward the beginning of the drive, reducing the amount of searching the drive heads have to do to locate a file. The drive in this example is not a system drive, nor does it have a paging file which would be indicated by the lime green Unmovable Files color. After the defragmentation process completes, clicking the View Report button will bring up the Defragmentation Report (Fig. 05). It takes the exact same form as the Analysis Report (Fig. 03) but shows the post defragmentation results. The Total Files and Average File Size remain identical, but notice that Total Fragmented Files and Total Excess Fragments have been reduced to zero (0) and the Average Fragments Per File is now 1.00, indicating most or all of the files are contiguous. In addition, there are no files listed that did not defragment.