1954: IBM builds the first calculating machine to use solid-state transistors instead of vacuum tubes.
IBM already had a business selling calculating machines, and it was humming along quite nicely. The IBM 604 Electronic Calculating Punch, which IBM introduced in 1948, was a desk-sized cabinet that ate and spat out punch cards in its single-minded mission of calculating math problems — 20 to 40 addition, subtraction, multiplication or division problems for each card. Since it could process 100 cards per second, that was a lot of math … for the time.
via October 7, 1954: IBM Gets Transistorized | This Day In Tech | Wired.com.