Scheme 48 is an implementation of the Scheme programming language as
described in the Revised5 Report on the Algorithmic Language Scheme.
It is based on a compiler and interpreter for a virtual Scheme
machine. Scheme 48 tries to be faithful to the Revised5 Scheme
Report, providing neither more nor less in the initial user
environment. It is based on a byte-code interpreter and is designed to
be used as a testbed for experiments in implementation techniques and
as an expository tool.
From Aaron Hsu <arcfide@sacrificumdeo.net>