About Defragging Hard Drives Tutorial Home >Music and Video >Digital Music >Digital Hardware Requirements >Maintaining Your Hard Drive >About Defragging Hard Drives   Step 1:  Fragmenting in Hard Drive Hard drive fragmentation occurs when files are deleted, leaving physical spaces between the remaining files. While the operating system is designed to consider it a priority to write each file as contiguous data, it also is designed to use any available area to the drive's full capacity. Consequently, files are written piecemeal to various small available areas scattered throughout the drive. After a period of use, many files are thus "fragmented."   Step 2:  Minimize Fragmentation Fragmentation is harmful because to read an existing file or write a new file, the drive's head must scan back and forth to various locations on the drive. This slows down the data rate of the drive, but also causes it to wear out more rapidly and introduces the increased possibility of read and write errors.   Step 3:  What Is Defragmentation? Defragmentation is the process of reading files, storing them in memory, and then rewriting them as physically contiguous data. To do this, the defragmentation program must juggle and shuffle files until all of them have been recopied to new locations as complete files. This results in increased drive speed and reliability.   Step 4:  Performing Defragmentation All versions of Windows have built-in defragmentation utilities. Note that this capability was not implemented in Windows NT® for the NT file system (NTFS), so to defrag your NTFS drives in Windows NT, you must purchase a defrag utility from a third-party supplier, such as Norton or Symantec. Windows NT does use defrag.exe to defragment disks formatted using the less efficient and older FAT (file allocation table) system, and subsequent versions of Windows utilizing NTFS allow for defragmentation of NTFS drives.