Matt,
Nick Montfort's paper "Continous Paper" made me think if there was a marked experiential difference between punch cards and tape. I am thinking about the metaphorics of stacks which harken to storage and the metaphorics of length (running a program). Just wondering if the day to day encouter with media influeces how the "what is" of the machine gets conceived.

On another note: Robert Bringhurst in The Elements of Typographic Style writes "Typewriters came to have upper- and lowercase letters but uppercase numbers alone. And from typewriters have come computer keyboards." (2002, p. 48)