basic list maintenance (add, delete, modify entries)
delete - modify, NOT in a circular

duplicate and/or checksum protected header
checksum - header, NOT in a circular

careful order of operations when updating header while adding/deleting entries
header - deleting, NOT in a circular

support for working on a limited portion of thelist at time
working on a limited portion, NOT in a circular

You have some basic misconceptions about what a circular buffer is.

Erik