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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>Fortuitously, I am about to mark up the final changes on the page proofs of <i>ENIAC In Action: Making and Remaking the Modern Computer</i> by Haigh, Priestley & Rope and ftp them back to MIT Press. The book should be out very early next year and it has a great deal to say in answer to your question. We have some explicit discussion of ENIAC as an artifact that bridges the transition from WWII to the Cold War, and explore in detail its use for atomic bomb and artillery calculations.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>Artillery trajectory calculations: these were, as you might expect given that the machine was being funded explicitly to perform them, absolutely vital to the design of ENIAC. Contrary to previous claims that ENIAC programming was an afterthought tackled only in late-1945 they were treated in detail very early in the design process, playing a vital role in shaping the machine’s ultimate configuration. This includes sketches of a suitable configuration in the initial proposal and detailed diagrams of how the problem would be tackled produced in late-1943. This has been a sensitive topic because discussion of early machines is very partisan. ENIAC-bashers have liked to claim it was a “special purpose” and very limited machine. In response, ENIAC boosters have downplayed the importance of the trajectory application to shaping the machine’s design. The truth is that ENIAC was extremely flexible, but the archival records clearly show that key new developments such as the conditional branch sprang from consideration and generalization of the very specific requirements encountered when planning the trajectory calculations. (Rather than, as some writers imply, from the computer builders of the 1940s having read Turing’s paper and then rushed down to the machine shop to try and build a universal machine). We also give a nice clear explanation of what the computations actually were, and how they fit into the larger process of creating firing tables (which began with the gathering and analysis of data from actual test firings). One of the many things that Walter Isaacson gets wrong about ENIAC is his claim that it was never actually used to compute trajectories. In fact ENIAC was already doing real work on this problem by August 1946, still at the Moore School, and once running smoothly at Aberdeen Proving Ground from 1949 to 1955 spent about 20% of its time calculating trajectories.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>ENIAC’s very first application, from December 1945 into the spring of 1946, was to check the validity of Teller’s basic approach to a hydrogen bomb, the Super. This work does remain classified, but fortunately is covered in some depth from the Los Alamos perspective in an excellent dissertation written with access to classified sources: </span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>Fitzpatrick, Anne. <u>Igniting the Light Elements: The Los Alamos Thermonuclear Weapon Project, 1942-1952 (LA-13577-T)</u>. Los Alamos, NM: Los Alamos National Laboratory, 1999.</span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'> In the book we draw on this heavily to make up for the inaccessibility of Los Alamos sources.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>Many other problems run on ENIAC were also concerned with atomic weapons, include the first computerized Monte Carlo computations, which receive two chapters in the book. Monte Carlo programs were run between 1948 and 1950, and included fission weapon simulations for Los Alamos, fission power simulations for Argonne, and a second wave of fusion calculations for Teller. An earlier version of the section discussing the initial 1948 fission Monte Carlos in an already published article, “Los Alamos Bets on ENIAC” which is available online at <a href="http://eniacinaction.com/the-articles/3-los-alamos-bets-on-eniac-nuclear-monte-carlo-simulations-1947-8/">http://eniacinaction.com/the-articles/3-los-alamos-bets-on-eniac-nuclear-monte-carlo-simulations-1947-8/</a>. From the same page you can access some supporting materials, including a report written by Klara von Neumann, the full flow diagram, and an annotated version of the original code. This is of particular historical interest because it is not only the first computerized Monte Carlo program but also the first modern code to be run on any computer. (By that, we mean a program expressed as a series of instructions run from addressable memory with jumps, subroutines, and the other features of EDVAC-style programs). There may well be material related to these in the Metropolis papers, which were not accessible to us, but even without that they appear to be the best documented programs run on any computer in the 1940s as surviving materials include a succession of flow diagrams that serve as a window into the design process.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>Best wishes,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>Tom<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>From:</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> Members [mailto:members-bounces@lists.sigcis.org] <b>On Behalf Of </b>Daniel Ferrell<br><b>Sent:</b> Thursday, August 27, 2015 12:41 PM<br><b>To:</b> members@sigcis.org<br><b>Subject:</b> [SIGCIS-Members] ENIAC and the Cold War<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal><span style='color:#666666'>SIGCIS members:</span><span style='font-family:"Calibri",sans-serif'><o:p></o:p></span></p><div><p class=MsoNormal style='margin-bottom:12.0pt'><span style='color:#666666'> I have an inquiry into ENIAC. I understand that one of its purposes was to track and calculate artillery trajectories. I am looking for resources that emphasize the development of ENIAC against the backdrop of the Cold War era, including the role ENIAC had in analyzing the hydrogen bomb. Are there any suggestions?<br id=FontBreak><br></span><span style='font-family:"Calibri",sans-serif'><o:p></o:p></span></p><div><div><p class=MsoNormal><b><span style='font-family:"Garamond",serif'>-Daniel Ferrell<o:p></o:p></span></b></p></div></div><div><p class=MsoNormal><span style='font-family:"Calibri",sans-serif'><o:p> </o:p></span></p><div><p class=MsoNormal><i><span style='font-family:"Garamond",serif'>Home Acceptance Corporation </span></i><span style='font-family:"Garamond",serif'>(NMLS #1151715)<i>. </i><br>65 S. Outer Rd.<br>P.O. Box 72<br>Benton, MO 63736</span><span style='font-family:"Calibri",sans-serif'><o:p></o:p></span></p></div></div></div></div></div></body></html>