I think the original didn't have the code book, so it took a long time to get a game started because both sides had to manually enter every space of every ship. Then they added the code book which entered all your ships at once for you when you typed in a code.
The versions with the code book allowed manual ship positioning as well, but you didn't have to enter every space of every ship - just the location of one end and the direction it was facing (north/south/east/west). It would verify that this didn't clash with any of the ships you'd already placed. It was quick enough.