Actually I have been around physicists. In my experience they use “codes” for any amount of code. If A wrote some software, B might say “I’d like to use your co

Actually I have been around physicists. In my experience they use “codes” for any amount of code. If A wrote some software, B might say “I’d like to use your codes.” That reference you give doesn’t appear to be available online but I’ll take your word for it.