Commodore 64
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“I first touched a computer keyboard in a junior-high BASIC programming class, and the first thing I produced on a computer was a high-school term paper written on a Commodore 64.”
Margaret O'Mara Interview, Historian, professor · via Uses This 

“Thinking back, avoiding repetitive tasks has been key in a lot of what I have done, even back when I was 12 and got my first computer (C64).”
Allan Odgaard Interview, Mac developer (TextMate) · via Uses This