Relay computerswhy so few 20
I must disagree. After WW II there was a tremendous need for computing horsepower. IBM sold out a prototype electronic calculator (Type 603, part of its punched card tabulating line) very quickly to its surprise*. Its subsequent improved model, the 604, was extremely popular. Some customers modified the 604 on their own to be more sophisticated and IBM took that to become the CPC machine. The CPC was a poor man's computer. It wasn't very sophisticated, but it was cheap compared to real computers available.
WW II brought out a lot of advancements in science and engineering, and sophisticated calculators were needed to process it all. The Cold War got govt contracts to build advanced planes and nuclear weapons all of which required lots of computations.
Relay computerswhy so few 21
Eric Sosman A similar test was staged just a couple years ago, when the American rail service Amtrak introduced high-speed "Acela" trains on the Washington-Philadelphia-New York-Boston route. ("High-speed...
Los Alamos used modified IBM tabulating machines (see above). During the war, only relay calculators were available, but these were wired up with tab machines to do repebreastive work (per Feynman).
The desk calculator work with people was slow and error prone. The machines would break down and doing a multiply or add was slow. The calculations were by necessity rough. Some theories had to wait until the ENIAC was available because it was so complex.