"I thought XP defrag was a version of Diskeeper?"
It basically is. The commercial version of Diskeeper shares a lot of the limitations of the built-in defragmenter:
- Requires 15-20% free space
- May require more than 1 pass
- May not consolidate free space (partition re-fragments faster)
- Requires Admin privs
- Doesn't defragment certain files
Ontrack's defragmenter isn't much better than the built-in defragmenter. It also lacks the ability to defragment certain files, etc...
- Greg/Raxco Software
Disclaimer: I work for Raxco Software, the maker of PerfectDisk - a commercial defrag utility and a competitor to Diskeeper, as a systems engineer in the support department.