“We present a file server/OS where threading and exceptions are all realized via delimited continuations. We use zipper to navigate within any term. If the term in question is a finite map whose keys are strings and values are either strings or other finite maps, the zipper-based file system looks almost the same as the Unix file system. Unlike the latter, however, we offer: transactional semantics; undo of any file and directory operation; snapshots; statically guaranteed the strongest, repeatable read, isolation mode for clients; built-in traversal facility; and just the right behavior for cyclic directory references.”

in “Continuations and delimited control” http://okmij.org/ftp/Computation/Continuations.html