By its very design, Windows NT/2000 does not allow a paging file on a disk volume to be defragmented online (when the computer is running and the operating system is fully started). This is due to data integrity issues related to the way Windows NT/2000 maintains the paging file.



More information:



During the developmental stages of Windows NT, defragmentation application programming interfaces (APIs) were developed and built into Windows NT to ensure that files could be moved safely—without data loss, system crashes, or corruption—while the operating system was running.



To ensure against data loss, system crashes and file corruption, the Windows 2000 Disk Defragmenter interoperates with the file system and APIs.



Disk defragmentation tools use the following process when defragmenting:



1. Locating the fragments of each file throughout the disk.

2. Copying them contiguously to a new location.

3. Verifying that the copy is an exact duplicate of the original.

4. Updating the Master File Table (MFT) so that the new file location is set.

5. De-allocating the old location and reclassifying it as free space.




When Windows 2000 starts up, disk space is allocated to the MFT and the Paging File for their exclusive use. It's important to know that the APIs that enable safe defragmentation do not support the movement of these files; as a result, they cannot be moved safely. Therefore, it's recommended that the MFT and the Paging File be defragmented when Windows 2000 is not running. But, because this places them beyond the range of routine defragmentation methods, the standard solution is to defragment the MFT and the Paging File during boot time, using a third-party, enterprise-level defragmenter.



Diskeeper does not defragment the paging file and MFT online. Taking all the above into account, is the SpeedDisk "proprietary" method fully supported by Microsoft?



Glenn Turner 6/26/2001 10:55:19 PM

Obviously the person doing the review is biased...No surprize to me that he picked Speed Disk as the best performing utility especially since they are a billion dollar company, with large advertising budgets. Now he has a problem with rebooting a system, but not with installing patches every time Microsoft comes out with a service pack? How many service packs did NT have? Do you think for a minute that I want to install 4 different patches on all 200 of my machines? This guy is crazy, saying that PerfectDisk 2000 scheduling is confusing, aren't IT professionals supposed to like added features? With Perfectdisk 2000 you can remotely schedule down to the partition or down to the exact file you want to defragg. Did this guy crawl out from the same rock as the last boob that evaluated the three products?

Chris McGuire 2/2/2001 1:35:19 PM