The peculiar input semantics of Pascal are a consequence of a locally
hacked-up version of NOS (I think that's the name) that ran on the big CDC
machines at ETH in Zurich. It was entirely a card-based system then, and
the way Pascal required read-ahead worked perfectly on that system, but not
really on any other, including other card-based, even NOS systems. I was
told this when I worked on that same machine as an exchange student working
at EIR outside Zurich, but not by Wirth himself. I couldn't bring myself to
ask him personally.