One malfunction had the potential to throw off ENIAC's entire calculation, and Eckert and Mauchly worked tirelessly to guard against potential kinks in the system. Telephone company workers were hired to do the wiring inside ENIAC, in hopes that their years of experience would enable them to produce the flawless wiring job necessary for the correct function of the computer. In order to determine the optimal type of wire to use, Eckert locked some mice in cages and starved them for several days. He then tempted their appetites with several different types of wire, and the brand they seemed to enjoy eating the least was the one selected for use in ENIAC. To prevent the almost 5,000 knobs used in the manufacture of ENIAC from getting loose too easily, Eckert designed his own knobs and secured them with specially made screws.
The photograph at right shows some of the ENIAC engineers working carefully to program the machine in the 1940s.
Pulled from The Franklin Institute Case Files, the document at right outlines the CSA investigation into the meticulously designed ENIAC.