Editing ENIAC (section)

==Comparison with other early computers==
{{main|History of computing hardware}}
<!--THIS ARTICLE IS ABOUT ENIAC. If you wish to add very detailed material about other computers, please consider adding it to that computer's own article or [[History of computing hardware]]. Happy editing! -->
[[File:ENIAC Pennsylvania state historical marker.jpg|thumb|250x250px|[[List of Pennsylvania state historical markers|Pennsylvania state historical marker]] on the [[University of Pennsylvania]]'s campus in [[Philadelphia]]]]

Mechanical computing machines have been around since [[Archimedes]]' time (see: [[Antikythera mechanism]]), but the 1930s and 1940s are considered the beginning of the modern computer era.

ENIAC was, like the IBM [[Harvard Mark I]] and the German [[Z3 (computer)|Z3]], able to run an arbitrary sequence of mathematical operations, but did not read them from a tape. Like the British [[Colossus computer|Colossus]], it was programmed by plugboard and switches. ENIAC combined full, [[Turing-complete]] programmability with electronic speed. The [[Atanasoff–Berry Computer]] (ABC), ENIAC, and Colossus all used [[vacuum tube|thermionic valves (vacuum tubes)]]. ENIAC's registers performed decimal arithmetic, rather than binary arithmetic like the Z3, the ABC and Colossus.

Like the Colossus, ENIAC required rewiring to reprogram until April 1948.<ref>See [[#Improvements]]</ref> In June 1948, the [[Manchester Baby]] ran its first program and earned the distinction of first electronic [[stored-program computer]].<ref>{{cite web |title=Programming the ENIAC: an example of why computer history is hard {{!}} @CHM Blog |date=2016-05-18 |website=Computer History Museum |url= https://www.computerhistory.org/atchm/programming-the-eniac-an-example-of-why-computer-history-is-hard/}}</ref><ref>{{cite journal |last1=Haigh |first1=Thomas |last2=Priestley |first2=Mark |last3=Rope |first3=Crispin |date=January–March 2014a |title=Reconsidering the Stored Program Concept |url=http://eniacinaction.com/the-articles/1-reconsidering-the-stored-program-concept/ |journal=IEEE Annals of the History of Computing |volume=36 |issue=1 |pages=9–10 |doi=10.1109/mahc.2013.56 |s2cid=18827916}}</ref>{{sfn|Haigh|Priestley|Rope|2014b|pp=48-54}} Though the idea of a stored-program computer with combined memory for program and data was conceived during the development of ENIAC, it was not initially implemented in ENIAC because World War II priorities required the machine to be completed quickly, and ENIAC's 20 storage locations would be too small to hold data and programs.

===Public knowledge===
The Z3 and Colossus were developed independently of each other, and of the ABC and ENIAC during World War II. Work on the ABC at [[Iowa State University]] was stopped in 1942 after [[John Atanasoff]] was called to [[Washington, D.C.]], to do physics research for the U.S. Navy, and it was subsequently dismantled.{{sfn|Copeland|2006|p=106}} The Z3 was destroyed by the Allied bombing raids of Berlin in 1943. As the ten Colossus machines were part of the UK's war effort their existence remained secret until the late 1970s, although knowledge of their capabilities remained among their UK staff and invited Americans. ENIAC, by contrast, was put through its paces for the press in 1946, "and captured the world's imagination". Older histories of computing may therefore not be comprehensive in their coverage and analysis of this period. All but two of the Colossus machines were dismantled in 1945; the remaining two were used to decrypt Soviet messages by [[GCHQ]] until the 1960s.{{sfn|Copeland|2006|p=2}}<ref>{{Citation |last=Ward |first=Mark |title=How GCHQ built on a colossal secret |work=BBC News |date=5 May 2014 |url=https://www.bbc.co.uk/news/technology-26714967}}</ref> The public demonstration for ENIAC was developed by Snyder and Jennings who created a demo that would calculate the trajectory of a missile in 15 seconds, a task that would have taken several weeks for a [[human computer]].<ref name=":4" />

===Patent===
{{main|Honeywell v. Sperry Rand}}
For a variety of reasons{{snd}}including Mauchly's June 1941 examination of the [[Atanasoff–Berry computer]] (ABC), prototyped in 1939 by [[John Atanasoff]] and [[Clifford Berry]]{{snd}}{{US patent|3120606}} for ENIAC, applied for in 1947 and granted in 1964, was voided by the 1973<ref>{{cite web| url = https://jva.cs.iastate.edu/courtcase.php | title = Atanasoff-Berry Computer Court Case | access-date = 2022-09-01}}</ref> decision of the landmark federal court case ''[[Honeywell, Inc. v. Sperry Rand Corp.]]''. The decision included: that the ENIAC inventors had derived the subject matter of the electronic digital computer from Atanasoff;  gave legal recognition to Atanasoff as the inventor of the first electronic digital computer; and put the invention of the electronic digital computer in the [[public domain]].