You're perfectly right, but performance of my system was fine without any further optimisation and there was no point in doing some dirty tricks to get more per

You're perfectly right, but performance of my system was fine without any further optimisation and there was no point in doing some dirty tricks to get more performance, even though the system had 32k or 64k RAM (I don't remember now). Also, often it is enough to optimise just a few critical places, not the whole thing.