Code is generally considered a mass noun among software engineers, but "codes" is pretty commonly used by academics, especially in other disciplines. In particular, physicists and mathematicians seem to use it pretty frequently, so that might explain why some in the HPC community use it as well.
I've also noticed that it seems more common among Europeans, but that might be just personal experience.
"Codes" tends to refer to error-correcting codes or encoding formats in my experience, while code refers to source or assembly code for machine execution.
One is a concept/idea/format while the other is a set of instructions.
Yup, British-educated here: programme for sequences of activities, program for the thing the computer runs... it’s just a little oddity I’ve noticed I’ve picked up and seem to be quite consistently applying.
Yes... and I use ”to programme” to denote the activity of planning activities, and ”to program” to indicate the process of coding instructions into a computer. I would probably use ”programme to program” if I ever had to discuss the idea of planning one’s intentions to issue instructions to a machine.
I've also noticed that it seems more common among Europeans, but that might be just personal experience.