From the Scheme 48 web page:

Scheme 48 is an implementation of Scheme written by Richard Kelsey and Jonathan Rees. 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.

To reproduce my results on Ubuntu Gutsy Gibbon, install Scheme 48 with

sudo apt-get install scheme-48

and run the interpreter with

scheme48 2>&1

Scheme 48 makes the following choices:

- Complies with the R5RS letrec specification even if the expressions being bound return more than once (via capturing and reentering their continuations). (more)
- Does not use ASCII to map integers to characters. (more)
- Represents promises as nullary procedures. (more)
- Supports arbitrary precision literal integers. (more)
- Supports arbitrary precision computed integers. (more)
- Supports the literal syntax for rational numbers (e.g. 1/2 is the literal number one half). (more)
- Supports the literal syntax for complex numbers (e.g. 1+i is the complex number with real and imaginary parts both 1). (more)
- Supports nontrivial exact rational numbers (e.g. (/ 1 3) produces an exact one third, not a floating point approximation). (more)
- Supports nontrivial exact complex numbers. (more)
- Guesses the denominators of inexact numbers per R5RS. (more)
- Requires subtraction and division to be binary (e.g. (- 3 4 5) is an error, not -6). (more)
- Does not define the procedure 'transcript-on'. (more)
- Does not define the procedure 'transcript-off'. (more)
- Does not define the procedure 'port?'. (more)