Yes yes, I am aware that '\n' writes a newline in UNIX while for Windows there is the two character sequence: '\r\n'. All this is very nice in theory, but my question is why? Why the carriage return character is extra in Windows? If UNIX can do it in \n why does it take Windows two characters to do this? 

I am reading David Beazley's Python book and he says:


  For example, on Windows, writing the
  character '\n' actually outputs the
  two- character sequence '\r\n' (and
  when reading the file back, '\r\n' is
  translated back into a single '\n'
  character).


Why the extra effort? 

I will be honest. I have known the difference for a long time but have never bothered to ask WHY. I hope that is answered today.

Thanks for your time.

Backward compatibility.

Windows is backward compatible with MS-DOS (aggressively so, even) and MS-DOS used the CR-LF convention because MS-DOS was compatible with CP/M-80 (somewhat by accident) which used the CR-LF convention because that was how you drove a printer (because printers were originally computer controlled typewriters).   

Printers have a separate command to move the paper up one line to a new line, and a separate command for returning the carriage (where the paper was mounted) back to the left margin.  

That's why.  And, yes, it is an annoyance, but it is part of the package deal that allowed MS-DOS to win over CP/M, and Windows 95 to win over all the other GUI's on top of DOS, and Windows XP to take over from Windows 98.

(Note: Modern laser printers still have these commands because they too are backwards compatible with earlier printers - HP in particular do this well)

For those unfamiliar with typewriters, here is a video showing how typing was done:  http://www.youtube.com/watch?v=LJvGiU_UyEQ.  Notice that the paper is first moved up, and then the carriage is returned, even if it happens in a simple movement.  The ding notified the typist that the end was near, and to prepare for it.
