Where the :// comes from...

Where the \:// comes from in \http://: "For HTTP, it was assumed that content may reside on different networks. Anyone who remembers the early Internet (pre-NREN, 1985 or so) will recall that there were LOTS of different, fragmented networks out there. CS-Net, CERFNet, BayNet, SesquiNet, etc. all served their little corners of the world. Some were TCP/IP, some were X.25, some were IBM-based, and all talked through gateways. The space between the slashes in a HTTP URL was originally supposed to be where the gateway or network name was specified. So a URL might have looked like "http:/csnet/www.somewhere.edu/file.html" if the modern Internet hadn't sprung out of its commercialization in 1991."