TransmitFile http://msdn.microsoft.com/library/en-us/winsock/winsock/transmitfile_2.asp http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fileio/base/i_o_completion_ports.asp http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fileio/base/createiocompletionport.asp http://www.sysinternals.com/ntw2k/info/comport.shtml http://msdn.microsoft.com/msdnmag/issues/1000/winsock/default.aspx Solaris 9: http://docs.sun.com/db/doc/816-5218/6mbcj7nrr?q=sendfile&a=view HP-UX: http://docs.hp.com/hpux/onlinedocs/B9106-90009/00/01/168-con.html AIX: http://publib16.boulder.ibm.com/pseries/en_US/libs/commtrf2/send_file.htm Solaris 10: http://developers.sun.com/solaris/articles/event_completion.html Linux: vmsplice (not in main kernel right now)