J. H. Felker and J. R. Harris created TRADIC, the first transistor driven computer at AT&T Bell Laboratories in 1955. No vacuum tubes, just 800 transistors, Not hot, but cold & highly efficient;
Power requirement = 100 watts
But even so, dear sister Anna, it was only a giant
3 cubic feet calculator!
I guessed beforehand that someone will fill the information hole and most probably ...