Editing Harvard Mark I (section)

==Successors==
The Mark I was followed by the [[Harvard Mark II]] (1947 or 1948), [[Harvard Mark III|Mark III/ADEC]] (September 1949), and [[Harvard Mark IV]] (1952) – all the work of Aiken. The Mark II was an improvement over the Mark I, although it still was based on electromechanical [[relay]]s. The Mark III used mostly [[electronic component]]s—[[vacuum tube]]s and [[crystal diode]]s—but also included mechanical components: rotating [[Drum memory|magnetic drums]] for storage, plus relays for transferring data between drums. The Mark IV was all-electronic, replacing the remaining mechanical components with [[magnetic core memory]]. The Mark II and Mark III were delivered to the [[United States Navy|US Navy]] base at [[Dahlgren, Virginia]]. The Mark IV was built for the [[United States Air Force|US Air Force]], but it stayed at Harvard.{{Citation needed|date=August 2019}}

The Mark I was disassembled in 1959, and portions of it went on display  in the [[Harvard Science Center|Science Center]], as part of the [[Harvard Collection of Historical Scientific Instruments]].  It was relocated to the new [[Harvard John A. Paulson School of Engineering and Applied Sciences|Science and Engineering Complex]] in [[Allston]] in July 2021.<ref name="Mark1Rebooted">{{cite web |last=Powell |first=Alvin |url=https://www.seas.harvard.edu/news/2021/07/mark-1-rebooted |website=Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) |title= Mark 1, rebooted |location=Cambridge, Massachusetts |publisher=President and Fellows of Harvard College |access-date=2021-07-28}}</ref> Other sections of the original machine had much earlier been transferred to IBM and the [[Smithsonian Institution]].<ref name="AtlasObs">{{cite web|title=Collection of Historical Scientific Instruments Mark I|url=http://www.atlasobscura.com/places/mark-i|website=Atlas Obscura|access-date=2016-05-24}}</ref>