Mac OS X 10.8.4 / Darwin Kernel Version 12.4.1: Tue May 21 17:04:50 PDT 2013; root:xnu-2050.40.51~1/RELEASE_X86_64 x86_64
> erl
Erlang R15B03 (erts-5.9.3.1) [source] [64-bit] [smp:4:4] [async-threads:0] [hipe] [kernel-poll:false] [dtrace]
Eshell V5.9.3.1  (abort with ^G)
1> <<Char:8,Rest/binary>> = <<"A",128>>.
<<65,128>>
2> unicode:characters_to_list(Rest).
{error,[],<<"A">>}
3> Rest.
<<128>>
4> Rest = <<128>>.
<<128>>
5> unicode:characters_to_list(<<128>>).
{error,[],<<128>>}