An implementation of an applicative file system

Abstract

A purely functional file system has been built on top of pure Scheme. It provides persistent structures and massive storage expected of file systems, without explicit side-effects like read and write. The file system becomes an additional, lazy argument to programs that would read from it, and ~n additional result from functions that would alter it. Functional programming on lazy structures replaces in-place side-effects with a significant storage management problem, handled by conjoining the heap to the file system. A hardware implementation of reference counting is extended out to manage sectors, as well as the primary heap. Backing it is a garbage collector of heap and of disk (i.e. UNiX’s fsck), needed only at reboot.