This version performed defragmentation adequately, but could run only interactively. In Windows 2000, Microsoft included the first version of the Disk Defragmenter utility. Although Microsoft did not include a defragmentation tool in the operating system, a few third-party software publishers produced successful defragmentation products for that operating system. This thinking was proven wrong, however, in the earliest versions of Windows NT, and an appropriate application program interface (API) was built into Windows NT 4 to support defragmentation. It was originally thought that because of the way NTFS functions, file fragmentation would not be an issue. One of the great features missing in Windows NT 4 and limited in Windows 2000 is the Disk Defragmenter utility. New & Noteworthy… Scheduling Disk Defragmenter Fragmentation occurs on every drive, but frequently updated drives are most susceptible to the performance degradation of fragmentation. The effect of fragmentation is to require more time to access the file, thus slowing performance. The file no longer occupies contiguous clusters and is fragmented multiple fragments of the file are spread out around the disk. The file system allocates new clusters to the file, some of which it already occupied and some of which are now on a different area of the disk. Later, your first file increases in size. Over time, additional files are written to the disk. If a file occupies clusters that are next to each other on disk, the file is said to occupy contiguous clusters. If the file is large enough, it will be written to multiple clusters.

As files are written to the drive, they are assigned to available areas of the disk (called clusters) by the file system. Assume that you are starting with a clean, freshly formatted hard drive. How data is arranged on a drive affects how fast the data is written to a drive or read from a drive. ShinderTechnical Editor, in MCSE (Exam 70-293) Study Guide, 2003 Arrangement of Data on Drives MCSE 70-293: Planning, Implementing, and Maintaining a High-Availability Strategy

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