[SIGCIS-Members] Book on Klára Dán von Neumann

thomas.haigh at gmail.com thomas.haigh at gmail.com
Sat Oct 23 09:13:04 PDT 2021

Hello Crystal and SIGCIS,


Crystal: good luck with the book. Klara von Neumann is, like Adele Goldstine, someone who has been arbitrarily excluded from the increasingly celebrated category of “Women of ENIAC” and I am very glad to see her getting more attention. 


She is the central character in chapters 8 and 9 of _ENIAC in Action_ which I wrote with Mark Priestly and Crispin Rope. There’s a summary of her contributions in a recent Twitter thread from Ananyo Bhattacharya whose new book on John von Neumann _The Man from the Future_ is published in Europe but not yet in the US. https://twitter.com/Ananyo/status/1447861621951504384 I have not read the whole book yet, but it has picked up some very positive reviews and I can confirm that his chapter on computing is well written and solidly researched.


General PSA in the interests of historical accuracy: Klara vN did some very important work on early computer programming, including coding what in ENIAC in Action we argue was the first “modern code” ever executed on any computer. She worked intensively with Los Alamos on nuclear Monte Carlo simulations from 1947 to 1950, and later codes run on the MANIAC computer at Los Alamos were based around her earlier ENIAC code. A copy of our ENIAC Monte Carlo poster hangs, I’ve been told, on the wall of the lunch break room of the current Los Alamos Monte Carlo group. (https://eniacinaction.com/the-book/eniac-monte-carlo-poster/)


However, I’ve seen two widely repeated errors about her contributions, which I’d hate to see incorporated in Crystal’s book or in the work of other members of the SIGCIS community.


1.	The ENAIC Monte Carlo simulations run in 1948 (and further “runs” in 1949) were not for the hydrogen bomb. They were for fission weapon designs. The mistaken claim that the 1948 calculations were for the “H-bomb” was, for example, repeated recently, by Alvy Ray Smith in the book that Brian Randell mentioned last week (p. 116). However, she was a core member of a group that returned to ENIAC in 1950 to run the Monte Carlo simulations that confirmed the non-viability of Teller’s proposed “Super” hydrogen bomb (ENIAC in Action, pages 203-204) That discovery led the actual H-Bomb in a slightly indirect fashion, by inspiring Ulam and Teller to produce an entirely different design.
2.	Contrary to claims made here (https://www.smithsonianmag.com/science-nature/meet-computer-scientist-you-should-thank-your-phone-weather-app-180963716/) in 2017 and now written, for example, into Wikipedia, Klara vN was not a key figure responsible for numerical weather prediction. (We describe the 1950 simulations in question on pages 214-220 of ENIAC in Action). She is credited in the footnote of a paper reporting the results of the simulation with tutoring the team responsible on ENIAC coding and desk-checking their code, and I have seen no evidence that her role in the calculations went beyond that. In particular she did not write the code in question, she did not travel with the group to Aberdeen for the calculations, and she did not work hands-on with the punch cards holding the data for the project. She did do all those things during several expeditions to Aberdeen, MD for the nuclear Monte Carlos, but not for the weather calculations. I know it is tempting to conclude that a woman thanked in a footnote for helping with something probably did most of the work for the entire project, but in this case that was not the case.


Bonus correction to another common ENIAC error, made by both Smith and the Smithsonian Magazine piece. Even after its 1948 reconfiguration to a new method of programming inspired by the “First Draft of a Report on the EDVAC,” ENIAC programs were not read from punched cards or loaded into writable electronic memory before execution. The programs were set by turning decimal switches on a large panel, which was functionally equivalent to later programmable ROM chip technology. (There was a card controlled mode, but it couldn’t branch and was used only for running diagnostics without disturbing the main code). Also, while I am here: all of you, please never anything ENIAC related binary. Not a trace of binary anywhere in the machine. 


Best wishes,





From: Members <members-bounces at lists.sigcis.org> On Behalf Of Crystal Bennes
Sent: Friday, October 22, 2021 10:46 AM
To: members at lists.sigcis.org
Subject: [SIGCIS-Members] Book on Klára Dán von Neumann




Some of you may have come across this already via Twitter,  but I wanted to share my upcoming photobook project,  <https://www.kickstarter.com/projects/632375787/klara-and-the-bomb> Klara and the Bomb, in the event that it might be of interest to some. Through the lens of the life and work of Klara von Neumann, the book charts connecting threads between the invention of modern computers, the history of nuclear weapons development in the United States, women programmers,  military photography and nuclear colonialism. The book combines archival research and historical images with my own fieldwork photographs, texts and interviews.


The book will be published in May 2022, and I am currently fundraising remaining printing costs through book pre-sales. The book is £35 (including UK postage, postage outside the UK is extra) and is available for pre-order here:



There are only 11 days remaining in the pre-order campaign, and I would be very grateful for any support from the SIGCIS community.


Very best wishes,




Crystal Bennes

Artist & Writer 


Cultural Negotiation of Science

Northumbria University

Newcastle upon Tyne, UK



crystal.bennes at northumbria.ac.uk <mailto:crystal.bennes at northumbria.ac.uk> 

website <https://crystalbennes.com/> 

twitter <https://twitter.com/home> 

instagram <https://www.instagram.com/crystalbennes/> 


Pre-order my forthcoming photobook, Klara and the Bomb <https://www.kickstarter.com/projects/632375787/klara-and-the-bomb> 


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