This one is for the OS X gurus.

Is it true that OS X 10.3 (or any builds since Darwin 7.0 Kernel) has automatic file de-fragmentation using 'Hot-File-Adaptive-Clustering'?

I have heard that, in these system configurations, when a file is accessed, a check is made to see if it is fragmented (i.e. split into several different sectors on the HD). If so, and if it is less than 20 MB in size, the filesystem will copy the file over to a contiguous area on the HD that will hold the file in it's entirety in contiguous sectors, and then free up the HD space the fragmented version used to occupy.

R.K.
---
Richard Kay
Hermitage of Enlightenment
Fremantle, Western Australia