@tobinbaker And in EBR you also have a third role, the writer, who is orphaning old items and thereby producing garbage that needs to be cleaned up eventually, but not so soon the readers will be affected, by attaching it to an epoch. So it's not enough to have one-way information flow/passive observers.
But yeah, certainly the "min" approach works well for linear/circular buffer truncation. You also see this in LMAX's Disruptor.