Formal comment #24 (defect) U+FFFD is not meant for encoding errors. Reported by: John Cowan Component: i/o Version: 5.91 The Unicode character U+FFFD is intended to represent a character in a non-Unicode encoding which is not representable within Unicode as currently defined. It is not intended to represent an encoding error. The Plan 9 OS uses U+0080, which has no Unicode or ISO defined meaning, to represent encoding errors. I suggest it. This affects error-handling-code in 15.3.3 (p. 87). RESPONE: The formal comment was withdrawn here: http://lists.r6rs.org/pipermail/r6rs-discuss/2006-September/000149.html