Cycling through files is the usual way dash cams achieve buffering. The size and number of files can be configurable (e.g. 300 files, 1 minute each). The oldest file gets deleted when a new one starts.

I wasn't aware of MyDicto either and I used to use Recaller all the time. Although I may have considered and dismissed it a year ago when I acquired my first N900. I have installed it now and having played with it for 5 minutes I must say I like Orecchiorette better. Perhaps a few features "borrowed" from MyDicto might make Orec the killer app of the year!