Post-NT versions of Windows come with a built-in defragmenter. However, you should consider investing in a third-party defragmenter because of the limits of the Windows utility.
As users delete, add and move files on their hard disks, fragmentation occurs, which hampers performance and can create unusable chunks of disk space scattered across the disk. The process of defragmentation rearranges the files on the hard disk so all of their sectors are contiguous. Until Windows 2000, Microsoft didn't provide a disk defragmenter, and users and administrators relied on third-party software.
Given the limits of Microsoft's Disk Defragmenter, using third-party software remains a wise idea. According to Microsoft, the following points are limitations of the built-in defragmenter: defragmentation of local volumes only and defragmenting only one volume at a time. The defragmenter cannot defragment one volume while scanning another. It may also take several passes through a volume to defragment it completely.
The original version in Windows 2000 has a number of additional limitations, such as not allowing automatic scheduled defragmentation and not defragmenting NT file system (NTFS) meta data files such as the Master File Table.
Several companies offer more capable disk defragmenters, including ones that run over a network. Among these companies are Raxco Software (www.raxco.co.uk) with PerfectDisk; and Executive Software International Inc.'s Diskkeeper (www.executive.com).
Windows' Disk Defragmenter is only useful for single-user systems where the user handles his or her own administration. No matter how cheap it is, it is not a good choice for even a small enterprise with a network.
This is basically Microsoft's conclusion as well. At the end of a tech note on its disk defragmenter (http://www.microsoft.com/windows2000/techinfo/administration/fileandprint/defrag.asp), Microsoft says:
"Disk Defragmenter is designed primarily for stand-alone machines and users with Administrator privileges. It is not intended to be used for network defragmentation. Administrators who require network controls, automatic scheduling, and the capability to simultaneously defragment multiple partitions, and MFT and paging files, should consider upgrading to a third-party, networkable defragmenter."
Rick Cook has been writing about mass storage since the days when the term meant an 80K floppy disk. The computers he learned on used ferrite cores and magnetic drums. For the last 20 years, Rick has been a freelance writer specializing in storage and other computer issues.