Myths about ENIAC
Myth: “ENIAC broke down too often to make it useful.”
Although ENIAC employed more than 17, pharm 000 tubes—devices which are prone to failure, like incandescent light bulbs—Pres Eckert’s circuit designs and the ENIAC’s modular architecture greatly improved both individual vacuum tube reliability and the speed at which tube failures could be isolated and replaced. According to Eckert, a tube would fail every couple of days and the problem could be fixed in about 15 minutes. The ENIAC had an extremely long life solving problems, running for nearly a decade before being shut down in October 1955. Before the ENIAC was built, many electronics experts were skeptical that a machine employing so many failure-prone elements could be made to be reliable; such skepticism was probably one of the reasons why no one had previously attempted to build a machine like the ENIAC.
Myth: “When ENIAC turned on, the lights in Philadelphia dimmed.”
According to Pres Eckert, “That story is total fiction… We took power off of the grid. We had voltage regulators to provide 150 kilowatts of regulated supply.”
Myth: “The ENIAC was built as part of a ‘Top Secret’ project during World War II.”
To be sure, the design and construction of the ENIAC under the Army-funded “Project PX” was classified and shrouded in secrecy. No one could enter the converted classroom in the University of Pennsylvania’s Moore School of Electrical Engineering where work on the computer was being conducted, except those with proper security clearances and identification. However, it was not, strictly speaking, “Top Secret”, a designation that didn’t exist in the United States prior to President Harry Truman’s Executive Order 8381 in 1950. During World War II, the three levels of classification were “Restricted”, “Confidential”, and “Secret”. Project PX was, from its inception and until its declassification in 1946, classified as “Confidential”.
-  3 C.F.R., 1949-1953 Comp., pp. 298-299. See also Congressional Record—Senate, Vol. 153, Pt. 1, page 151. January 4, 2007. ↩