The file sizes are too large for me to upload. Here are the links to d/l the files:

http://www.archive.org/download/JaybirdColeman-MistreatinMama/JaybirdColeman-MistreatinMama.mp3

http://www.archive.org/download/BigBillBroonzy-BabyPleaseDontGo1/BigBillBroonzy-BabyPleaseDontGo1.mp3

In addition to mp3 file, I also tried Excel file and cygwin executable file with the fluid cat command as shown below; none of them work:
   $ cat src > dest (executed in Fluid Shell)
   $ diff src dest (executed in cygwin after above is done; output is "Files src and dest differ)
where src can be a Excel file or a cygwin executable file; none of them work.

On the contrast, fluid shell cp command does the correct thing:
   $ cp src dest  (executed in Fluid Shell)
   $ diff src dest  (executed in cygwin after above is done; no difference)
where src can be a mp3 file, an Excel file or a cygwin executable program.

In turns of implementation, the difference between fluid cat and fluid cp is, cp reads/writes file contents as byte stream while cat converts file contents to character stream (using UTF-8 charset) before writing it out. I will discuss this with Niels tomorrow to see what's the best way to address this issue.

Applied the new shell I/O APIs to the cat command and all of the following test cases went through. Now cat command reads/writes its input/output in bytes.

=== Test cases ===
> cat src > dest (executed in fluid shell)
> diff src dest  (executed in cygwin, no difference)
> cat src | cat | cat > dest (executed in fluid shell)
> diff src dest  (executed in cygwin, no difference)
where src is one of the followings:
  an ASCII file
  an Excel file
  a MP3 file
  a cygwin executable program

Size and streaming when it is concatenated is fixed in 12.0.0-dev-62. Need to talk to Fung regarding cat of excel files