Some filesystems are designed to not "frag" in the first place... such as the Unix File System. Can files fragment? Certainly.
But, look at it this way: What is the smallest show you can record? 30 minutes. How many megs is that? Lots. And if you do stuff on HQ your at Gigs. So, in general the biggest fragment you might have is a Gig here or there.
Say you record everything in HQ, do and hour show, then a 30 minute show, then an hour then another 30. If you delete the first 30, the next show you record, say its an hour, may fill in the missing 30 then append at the end of the used space. That file may have two fragments... each of which is probably close to 1.2 Gigs. No biggy. Windows users would kill for those percentages. (Unix users need not worry... most of the time UFS and its variants, find contiguous space of the correct size. They also don't just find the first free block and use it. Which is why when duplicating a 4gig partition and you only have "used" 2 gigs, its a very bad idea to just copy the first 2 gigs of raw space.)
I realize I didn't do a very good job at explaining this, sorry.
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