>> Additionally, I can't understand why each line is terminated with >> <CR><LF>, why use two characters when one will do. > >Microsoft-OS text editors. Seriously. My, what a bunch of parvenus. SIP got it from SMTP, SMTP got it from Telnet. Back in the 1960s we all used <CR><LF> because on a mechanical model 33 or 35 Teletype, CR really returned the carriage, LF really advanced the platen, and you needed both. I first ran into CR/LF on a PDP-6 in about 1968, but I know it wasn't new then. A single LF to start a new line arrived with the model 37 Teletype, and Unix was, as far as I know, the first system to use just \n as the line terminator starting in the early 1970s. But by then the Arpanet protocols were designed, and the hassle of changing wasn't (and still isn't) worth it.