BEGIN:VCALENDAR VERSION:2.0 PRODID:-//InvisionCommunity Events 5.0.18//EN METHOD:PUBLISH CALSCALE:GREGORIAN REFRESH-INTERVAL:PT15M X-PUBLISHED-TTL:PT15M X-WR-CALNAME:RMCommunityCalendar NAME:RMCommunityCalendar BEGIN:VTIMEZONE TZID:Europe/London TZURL:https://tzurl.org/zoneinfo/Europe/London X-LIC-LOCATION:Europe/London BEGIN:DAYLIGHT TZOFFSETFROM:+0000 TZOFFSETTO:+0100 TZNAME:BST DTSTART:20250330T020000Z RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU END:DAYLIGHT BEGIN:STANDARD TZOFFSETFROM:+0100 TZOFFSETTO:+0000 TZNAME:GMT DTSTART:20251026T020000Z RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU END:STANDARD END:VTIMEZONE BEGIN:VEVENT SUMMARY:Electronic Numerical Integrator and Compiler (ENIAC) is the first computer + first machine to make a weather model to predict the weat her\, here is how 03/05/1950 DTSTAMP:20250301T221534Z SEQUENCE:0 UID:210-7-c3fe8195a3dde498d013e477e2142422@aalbc.com ORGANIZER;CN="richardmurray":noreply@aalbc.com DESCRIPTION:\n Electronic Numerical Integrator and Compiler (ENIAC) is t he first computer + first machine to make a weather model to predict the w eather\, here is how 03/05/1950\n\n https://aalbc.com/tc/blogs/entry/482-e lectronic-numerical-integrator-and-compiler-eniac-is-the-first-computer-fi rst-machine-to-make-a-weather-model-to-predict-the-weather-here-is-how/\n\ n\n\n  \n\n\n\n \n\n\n\n  \n\n\n\n IF YOU DONT WANT TO USE THE LINK ABOV E\n\n\n\n \n \n \n \n  \n \n\n \n How?\n \n\n \ n The first successful numerical prediction was performed using the E NIAC digital computer in 1950 by a team led by American meteorologist Ju le Charney. The team include Philip Thompson\, Larry Gates\, and Norwegian meteorologist Ragnar Fjørtoft\, applied mathematician John von Neumann \, and computer programmer Klara Dan von Neumann\, M. H. Frankel\, Jerom e Namias\, John C. Freeman Jr.\, Francis Reichelderfer\, George Platzman \, and Joseph Smagorinsky.[THE ENIAC FORECASTS A Re-creation ][The Unher alded Contributions of Klara Dan von Neumann][A Vast Machine] They used a simplified form of atmospheric dynamics based on solving the barotropi c vorticity equation over a single layer of the atmosphere\, by computing the geopotential height of the atmosphere's 500 millibars (15 inHg) pr essure surface.[Numerical Integration of the Barotropic Vorticity Equation ] This simplification greatly reduced demands on computer time and memory \, so the computations could be performed on the relatively primitive comp uters of the day.[https://archive.org/details/stormwatcherstur00cox_df1/pa ge/208/mode/2up] When news of the first weather forecast by ENIAC was rec eived by Richardson in 1950\, he remarked that the results were an \"enorm ous scientific advance.\"[The origins of computer weather prediction and   climate modeling] The first calculations for a 24‑hour forecast took ENIAC nearly 24 hours to produce\,[The origins of computer weather predi ction and  climate modeling] but Charney's group noted that most of tha t time was spent in \"manual operations\"\, and expressed hope that foreca sts of the weather before it occurs would soon be realized.[Numerical Inte gration of the Barotropic Vorticity Equation]\n \n\n \n  \n \n\n \n ARTICLES\n \n\n \n  \n \n\n \n THE ENI AC FORECASTS A Re-creation \n \n\n \n https://maths.ucd.ie/~ply nch/Publications/ENIAC-BAMS-08.pdf\n \n\n \n            \n \n\n \n  \n \n\n \n The Unheralded Contributions of Klara Dan von Neumann\n\n https://www.smithsonianmag.com/science-n ature/meet-computer-scientist-you-should-thank-your-phone-weather-app-1809 63716/\n \n\n \n Despite having no formal mathematical training\ , she was a key figure in creating the computer that would later launch mo dern weather prediction\n \n\n \n Sarah Witman\n \n\n \n June 16\, 2017\n\n  \n \n\n \n Editor's note\, May 20\, 2021: We’ve updated this piece to more accurately reflect Klara Dan von Neumann’s contributions to the experiment that resulted in the first nu merical weather predictions in 1950. The piece originally misstated that K lara was in charge of hand-punching and managing the 100\,000 punchcards t hat served as the ENIAC’s read/write memory\, when in fact she wasn’t present for this part of the experiment. The story has been re-edited to r eflect this information.\n \n\n \n  \n \n\n \n A wea ther app is a nifty tool that predicts your meteorological future\, levera ging the strength of satellites\, supercomputers\, and other modern device s to tell you when to pack an umbrella. Today\, computerized weather predi ction—like moving pictures or seatbelts in cars—is so commonplace that most smartphone users don’t give it a second thought. But in the early 20th century\, the idea that you might be able to forecast the weather day s or even weeks ahead was a tantalizing prospect.\n\n One of the most impo rtant breakthroughs in weather forecasting took place in the spring of 195 0\, during an experiment at the Aberdeen Proving Ground\, a U.S. Army fac ility in Maryland. For 33 days and nights\, a team of scientists and compu ter technicians worked tirelessly to achieve something that meteorologists had been working toward for decades: predict the weather mathematically.\ n\n This was well before the age of pocket-sized\, or even desktop\, compu ters. The team—led by scientists Jule Charney\, Ragnar Fjørtoft\, John Freeman\, George Platzman\, and Joseph Smagorinsky—was using one of the world’s first computers: a finicky\, 150-foot machine called ENIAC that had been developed during the recent World War. Platzman would later desc ribe a complicated\, 16-step process they repeated over and over: six ste ps for the ENIAC to run their calculations\, and 10 steps to input instruc tions and record output on punch-cards. Minor errors forced them to redo h ours—sometimes days—of work. In one tense moment\, a computer operat or’s thumb got caught in the machinery\, temporarily halting operations. \n\n But at the end of the month\, the team had produced six groundbreakin g weather forecasts (well\, technically\, \"hindcasts\,\" since they used data from past storms to demonstrate the method). An article in the New York Times hailed the project as a way to “lift the veil from previousl y undisclosed mysteries connected with the science of weather forecasting. ” The benefits to agriculture\, shipping\, air travel and other industri es “were obvious\,” weather experts told the Times\, offering the pote ntial to save crops\, money\, and lives.\n\n An internal Weather Bureau m emo commended “these men” for proving that computer-based forecasting \, the cornerstone of modern weather prediction\, was possible. This was m ostly true—except\, it wasn’t just men. Numerous women played critical scientific roles in the experiment\, for which they earned little to no c redit at the time.\n\n \n\n \n \n \n\n \n Two computer operators\, Ruth Lichterman (left) and Marlyn Wescoff (right)\, wire the right side of the ENIAC with a new program in the pre-von Neumann era. US Army\, via Historic Computers Images of the ARL Technical Library\n \n \n \n Like the ENIAC’s first programmers—Jean Bartik\, Betty Holberton\, Kathleen Antonelli\, Marlyn Meltzer\, Ruth Teitelbaum\, and Fr ances Spence—the computer operators for the 1950 weather experiment were all women. While this highly skilled work would surely have earned them a co-authorship today\, their names—Norma Gilbarg\, Ellen-Kristine Eliass en\, and Margaret Smagorinsky\, who was the first female statistician hi red by the Weather Bureau and the wife of meteorologist Joseph Smagorinsky —are absent from the journal article detailing the experiment’s resul ts. Before most of the scientists arrived at Aberdeen\, these women spent hundreds of hours calculating the equations that the ENIAC would need to c ompute in the full experiment. “The system that they were going to use o n the big computer\, we were doing manually\,” Margaret recalled in an  interview with science historian George Dyson before she died in 2011. “It was a very tedious job. The three of us worked in a very small room\ , and we worked hard.”\n\n But perhaps the biggest single contribution\, aside from the scientists leading the experiment\, came from a woman name d Klara Dan von Neumann.\n\n Klara\, known affectionately as Klari\, was  born into a wealthy Jewish family in Budapest in 1911. After World War I\ , in which Hungary allied with Austria to become one of the great Europe an powers of the war\, Klara attended an English boarding school and becam e a national figure skating champion. When she was a teenager\, during Bud apest’s roaring '20s\, her father and grandfather threw parties and invi ted the top artists and thinkers of the day—including women.\n\n Klara  married young\, divorced and remarried before the age of 25. In 1937\, a Hungarian mathematician\, John von Neumann\, began to court her. Von Neum ann was also married at the time\, but his divorce was in progress (his fi rst wife\, Mariette\, had fallen in love with the acclaimed physicist J.B. Horner Kuper\, both of whom would become two of the first employees of Long Island’s Brookhaven National Laboratory). Within a year\, John and Klara were married.\n\n John had a professorship at Princeton University\, and\, as the Nazis gained strength in Europe\, Klara followed him to the U.S. Despite only having a high school education in algebra and trigonome try\, she shared her new husband’s interest in numbers\, and was able to secure a wartime job with Princeton’s Office of Population Research inv estigating population trends.\n\n By this time\, John had become one of th e most famous scientists in the world as a member of the Manhattan Projec t\, the now-notorious U.S. government research project dedicated to buildi ng the first atomic bomb. With his strong Hungarian accent and array of ec centricities—he once played a joke on Albert Einstein by offering him a ride to the train station and then intentionally sending him off on the wrong train—he would later become the inspiration for Stanley Kubric k’s Dr. Strangelove. While Klara stayed behind\, working full-time at Princeton\, John moved out to Los Alamos\, New Mexico\, running the thousa nds of calculations needed to build the first of these weapons of mass des truction. His work came to fatal fruition in 1945\, when the U.S. dropped two atomic bombs on Japan\, killing as many as 250\,000 people.\n\n \n \n \n \n \n\n \n A chart of the series of operations requ ired to create the first weather forecasts\, chronicled later by scientist George Platzman. AMS Bulletin\, ©American Meteorological Society. Used with permission.\n \n\n \n After the war\, John decided to tu rn his mathematical brilliance toward more peaceful applications. He thoug ht he might be able to use the ENIAC—a powerful new computer that cut it s teeth running calculations for an early hydrogen bomb prototype—coul d be applied to help improve weather forecasting.\n\n As John began to pu rsue this idea\, getting in touch with top meteorologists in the U.S. and Norway\, Klara came to visit him in Los Alamos. Living apart during the Ma nhattan Project had been hard on their marriage\, and Klara had suffered a miscarriage back in New Jersey\, but the trip rekindled sparks between th em. By this time\, Klara had become quite mathematically adept through her work at Princeton\, and she and John began to collaborate on the ENIAC.\n \n “I became Johnny’s experimental rabbit\,” she told Dyson years afterward. “I learned how to translate algebraic equations into numerica l forms\, which in turn then have to be put into machine language in the o rder in which the machine has to calculate it\, either in sequence or goin g round and round\, until it has finished with one part of the problem\, a nd then go on some definite which-a-way\, whatever seems to be right for i t to do next.”<\;br>\;\n <\;br>\;\n The work was challenging\, e specially compared to modern computer programming with its luxuries like b uilt-in memory and operating systems. Yet\, Klara described to Dyson\, sh e found coding to be a “very amusing and rather intricate jigsaw puzzl e.”\n\n \n\n \n \n \n\n \n Women computer scientists holding different parts of an early computer. From left to right: Patsy S immers\, holding ENIAC board\; Gail Taylor\, holding EDVAC board\; Milly B eck\, holding ORDVAC board\; Norma Stec\, holding BRLESC-I board. US Army Photo\, via Historic Computers Images of the ARL Technical Library\n \ n\n \n In the acknowledgements of the 1950 paper detailing the f irst numerical weather predictions\, the authors thank Klara for her “in struction in the technique of coding for the ENIAC and for checking the fi nal code.” But what is undoubtedly her most impactful contribution to th e experiment took place several years prior: helping to transform the ENIA C from a rigidly hard-wired machine into one of the first stored-program  computers\, more akin to today’s personal computers. Both Klara and Jo hn felt this was a necessary improvement for future applications like the weather experiment\, as it would allow them to store a vast repertoire of commands in the computer’s memory.\n\n In 1947\, Klara and Nick Metropol is—a Greek-American mathematician and computer scientist\, and leader of the Los Alamos computing group—collaborated on a plan to implement thi s new mode on the ENIAC\, and in 1948 they traveled to Aberdeen to reconfi gure the machine. After training five other people to program and run the ENIAC (two married couples and a bachelor: Foster and Cerda Evans\, Harris and Rosalie Mayer\, and Marshall Rosenbluth)\, they worked for 32 days st raight to install the new control system\, check it\, and get the modified machine up and running. By the end of the trip\, Klara had reportedly los t 15 pounds\, and it took her several weeks and numerous doctor’s visits to recover from the experience. But she still managed to write a full re port on the conversion and use of the ENIAC as a stored-program computer. “The method is clearly a 100% success\,” John wrote at the time.\n\n By the time Charney and his team of scientists arrived at Aberdeen in earl y 1950\, Platzman would recall years later\, the “ENIAC had been operat ing in the new stored-program mode for over a year\, a fact that greatly s implified our work.” In a letter to his wife written during this first w eek\, Platzman gushed: “The machine is a miracle.” The ENIAC was still rudimentary: It could only produce 400 multiplications per second\, so s low that it produced rhythmic chugging noises. But after working around th e clock for over a month\, the team had six precious gems to show for thei r efforts: two 12-hour and four 24-hour retrospective forecasts.\n\n Not l ong after the weather experiment concluded\, tragedy befell the von Neuman n family. John von Neumann was confined to a wheelchair in 1956\, and succ umbed to cancer a year later\, (likely due\, at least in part\, to his pro ximity to radiation during the Manhattan Project). Klara wrote the preface to his posthumous book\, The Computer and the Brain\, which she presente d to Yale College in 1957. In it\, she briefly described her late husb and’s contributions to the field of meteorology\, writing that his “nu merical calculations seemed to be helpful in opening entirely new vistas\, ” but gave no mention of her own role.\n\n Klara’s work with computers seems to have tapered off even before John’s death. Whatever her reason ing may have been for this\, it was in line with the prevailing trend at t he time. Janet Abbate recounts in her 2012 book Recoding Gender how\, as the public perception of computers and their value to society evolved thr oughout the 1950s and ’60s\, the number of women hired for those roles s hrank rapidly. Abbate writes that\, while the women who made up most of th e workforce in the early days of coding “would have scoffed at the notio n that programming would ever be considered a masculine occupation\,” th at’s exactly what happened within a matter of years. Today\, less than 8 percent of software developers worldwide identify as women\, nonbinary\ , or gender nonconforming.\n\n While female representation in the fields o f science\, technology\, engineering\, and math has increased as a whole s ince the 1970s\, according to the U.S. Census Bureau\, the number of wome n working in computing roles has actually declined over the past few decad es. But without their early contributions to the field\, we might have mis sed out on the breakthrough that led to modern weather prediction\, or any number of scientific advancements. So the next time you scroll through yo ur weather app before deciding whether to don a raincoat\, think of Klara and the other women who helped make it possible.\n\n \n\n \n  \ n \n\n \n A Vast Machine\n\n https://web.archive.org/web/201 20127215929/http://mitpress.mit.edu/catalog/item/default.asp?ttype=2&\; tid=12080\n \n\n \n Computer Models\, Climate Data\, and the Pol itics of Global Warming\n\n Paul N. Edwards\n \n\n \n  Tabl e of Contents and Sample Chapters\n \n\n \n Computer Models\, Cl imate Data\, and the Politics of Global Warming\n\n Paul N. Edwards\n \n\n \n Acknowledgments\n\n Download Chapter as PDF Sample C hapter - Download PDF (71 KB)    ix\n\n Introduction\n\n Downlo ad Chapter as PDF Sample Chapter - Download PDF (121 KB)    xiii\n\n 1    Thinking Globally\n\n Download Chapter as PDF Sample Chapter - Download PDF (1.82 MB)    1\n\n 2    Global Space\, Universal Time\n\n Seeing the Planetary Atmosphere    27\n\n 3    Sta ndards and Networks\n\n International Meteorology and the Réseau Mond ial    49\n\n 4    Climatology and Climate Change before World War II    61\n\n 5    Friction    83\n\n 6    Numerica l Weather Prediction    111\n\n 7    The Infinite Forecast    139\n\n 8    Making Global Data    187\n\n 9    The First WWW    229\n\n 10    Making Data Global    251\n\n 11    Data Wars    287\n\n 12    Reanalysis\n\n The Do-Over    323\n\n 13    Parametrics and the Limits of Knowl edge    337\n\n 14    Simulation Models and Atmospheric Politics \, 1960–1992    357\n\n 15    Signal and Noise\n\n Consens us\, Controversy\, and Climate Change    397\n\n Conclusion    4 31\n\n Notes    441\n\n Index\n\n Download Chapter as PDF S ample Chapter - Download PDF (106 KB)    509\n\n  \n \n\n \n Global warming skeptics often fall back on the argument that the scie ntific case for global warming is all model predictions\, nothing but simu lation\; they warn us that we need to wait for real data\, \"sound science .\" In A Vast Machine Paul Edwards has news for these skeptics: without mo dels\, there are no data. Today\, no collection of signals or observations —even from satellites\, which can \"see\" the whole planet with a single instrument—becomes global in time and space without passing through a s eries of data models. Everything we know about the world's climate we know through models. Edwards offers an engaging and innovative history of how scientists learned to understand the atmosphere—to measure it\, trace it s past\, and model its future.\n \n\n \n Edwards argues that all our knowledge about climate change comes from three kinds of computer mod els: simulation models of weather and climate\; reanalysis models\, which recreate climate history from historical weather data\; and data models\, used to combine and adjust measurements from many different sources. Meteo rology creates knowledge through an infrastructure (weather stations and o ther data platforms) that covers the whole world\, making global data. Thi s infrastructure generates information so vast in quantity and so diverse in quality and form that it can be understood only by computer analysis— making data global. Edwards describes the science behind the scientific co nsensus on climate change\, arguing that over the years data and models ha ve converged to create a stable\, reliable\, and trustworthy basis for est ablishing the reality of global warming.\n \n\n \n About the Aut hor\n \n\n \n Paul N. Edwards is Professor in the School of Info rmation and the Department of History at the University of Michigan. He is the author of The Closed World: Computers and the Politics of Discourse i n Cold War America (1996) and a coeditor (with Clark Miller) of Changing t he Atmosphere: Expert Knowledge and Environmental Governance (2001)\, both published by the MIT Press.\n\n  \n \n\n \n Numerical Inte gration of the Barotropic Vorticity Equation\n\n https://a.tellusjourn als.se/articles/10.3402/tellusa.v2i4.8607\n \n\n \n Original Res earch Papers\n\n Authors\n\n J. G. Charney\n\n R. Fjörtoft\n\ n J. von Neumann\n \n\n \n Abstract\n\n A method is give n for the numerical solution of the barotropic vorticity equation over a l imited area of the earth’s surface. The lack of a natural boundary calls for an investigation of the appropriate boundary conditions. These are de termined by a heuristic argument and are shown to be sufficient in a speci al case. Approximate conditions necessary to insure the mathematical stabi lity of the difference equation are derived. The results of a series of fo ur 24-hour forecasts computed from actual data at the 500 mb level are pre sented\, together with an interpretation and analysis. An attempt is made to determine the causes of the forecast errors. These are ascribed partly to the use of too large a space increment and partly to the effects of bar oclinicity. The rôle of the latter is investigated in some detail by mean s of a simple baroclinic model.\n \n\n \n                   \n \n\n \n  \n \n\n \n The or igins of computer weather prediction and  climate modeling\n\n https ://web.archive.org/web/20100708191309/http://www.rsmas.miami.edu/personal/ miskandarani/Courses/MPO662/Lynch\,Peter/OriginsCompWF.JCP227.pdf\n\n from \n\n  Peter Lynch\n \n\n \n               \n \n\n \n  \n \n\n \n IN AMENDMENT\n \n\n \n  \n \n\n \n Reading the Manual for ENIAC\, the World’s F irst Electronic Computer\n\n https://thenewstack.io/reading-the-manual -for-eniac-the-worlds-first-electronic-computer/\n \n\n \n ENIAC (Electronic Numerical Integrator and Compiler) was the world's very first fully electronic general-purpose computer. Smithsonian magazine once call ed it \"the room-size government computer that began the digital era.\" An d last week the I Programmer site shared a link to an original operating m anual for ENIAC\, originally published 75 years ago this month.\n\n Ju n 16th\, 2019 6:00am by David Cassel\n \n\n \n I don't know my l ove\, I know a business exist. Michael jackson was a huge client\, but he wasn't alone\, many black people in the entertainment industry have skin l ightened \, and the newspapers don't tend to go into it. \n \n\n \n \n \n\n \n Feature image: US Army photo of the ENIAC.\n\n Sometimes you have to take a long look back to realize just how much th ings have changed. And if you looked around our modern-day\, cloud-enhance d web this month\, you’d find several sites sharing memories about the l aunch of the ENIAC computer in 1946 — and of all those unstoppable mid-c entury engineers who tirelessly made it work.\n \n\n \n ENIAC (E lectronic Numerical Integrator and Compiler) was the world’s very first fully electronic general-purpose computer. Smithsonian magazine once calle d it “the room-size government computer that began the digital era.” A nd last week the I Programmer site shared a link to an original operating manual for ENIAC\, originally published 75 years ago this month.\n\n \ n \n\n \n It’s dated June 1st\, 1946 — it was published by t he school of engineering at the University of Pennsylvania in Philadelphia — and the manual’s page at Archive.org show it’s been viewed just 2 \,309 times. (“There are no reviews yet\,” reads the boilerplate on th e site. “Be the first one to write a review.”)\n \n\n \n  \ n \n\n \n \n \n\n \n  \n \n\n \n The archi ve identifies it as part of “the bitsavers.org collection” — a proje ct started by a software curator at the Computer History Museum\, with ove r 98\,500 files and more than 4.7 million text pages.\n\n So what can we g lean about the ENIAC’s moment in history from the manual which documents its operation?\n\n It seems like the machine was temperamental. For examp le\, it warns that the DC power should never be turned on without first tu rning the operation switch to “continuous.”\n\n “Failure to follow t his rule causes certain DC fuses to blow\, -240 and -415 in particular.” \n\n But the consequences are even worse if you opened the DC fuse cabinet when the D.C. power was turned on. “This not only exposes a person to v oltage differences of around 1\,500 volts but the person may be burned by flying pieces of molten fuse wire” (if one of the fuse cases suddenly bl ew). In fact\, the ENIAC was actually designed with a door switch shunt th at prevented it from operating if one of its panel doors was open\, “sin ce removing the doors exposes dangerous voltage.” But this feature could be bypassed by holding the door switch shunt in its closed position.\n\n In a video shared by the Computer History Archives Project\, chief enginee r J. Presper Eckert Jr remembers that it was rare to go more than a day or two without at least one tube blowing out.\n\n And in addition to potenti al shocks\, dust was another potential hazard. “Dust particles may cause transient relay failures\,” the manual warns\, “so avoid stirring up dust in the ENIAC room.”\n\n “Also\, if any relay case is removed\, al ways replace in exactly the same position in order not to disturb dust ins ide the case.”\n\n The ENIAC used an IBM card reader\, but that had its own issues too. At one point the manual actually recommends against having the same number in every column of a punchcard\, since “this weakens a card increasing the probability of ‘jamming’ in the feeding mechanism of the IBM machines.”\n\n Essential Instructions<\;br>\;\n Despite t hese limitations\, ENIAC was a remarkable piece of technology. The manual includes intricate drawings and detailed diagrams of its racks\, trays\, c ables\, and wiring. But most important are the front panel drawings\, whic h “show in some detail the switches\, sockets\, etc. for each panel of e ach unit.”\n\n \n\n \n “They contain the essential instructi ons for setting up a problem on the ENIAC.”\n\n \n \n\n \n  \n \n\n \n  \n \n\n \n ENIAC’s panels were equ ipped with neon lights corresponding to things like the “denominator fli p-flop” and the “divide flip-flop.” The manual includes footnotes th at carefully explain under what circumstances each light will be lit.\n\n “The square root of zero is perhaps the easiest test to repeat on the di vider-square rooter…”\n\n It’s not until page 28 that it explains th at turning on the start switch “starts the initiating sequences for the ENIAC\, turning on the DC power supplies\, the heaters of the various pane ls\, and the fans…” And it also turns on a little amber light.\n\n “ When this sequence has been completed\, showing that the ENIAC is ready to operate\, the green light goes on…”\n\n There were gates for a “con stant transmitter” (which transmits to an “accumulator”)\, and its c ircuitry included “program pulse input terminals” — for add pulses a nd subtract pulses. And the machine also included two “significant figur es switches.”\n\n “When 10 or more significant figures are desired\, t he left-hand switch is set to 10 and the right-hand switch set so that the sum of the two switch readings equals the number of significant figures d esired.”\n\n There are tantalizing glimpses of how it all works together . The manual recommends a complicated test to make sure all the hardware i s working properly. It involves a card with the value P 11111 11111\, whic h gets input into the machine’s “accumulator” 18 times. The mathemat ical result — 19\,999\,999\,998 — apparently exceeds the range of the accumulator\, so the expected result is actually M 99999 99998. Then a car d with the value P 00000 00001 is transmitted to the accumulators exactly twice — which instead of twenty billion (20\,000\,000\,000) should give the value P 00000 00000.\n\n “Note that this test assumes that the signi ficant figure switch is set to ’10’…”\n\n In Smithsonian magazine\ , technology writer Steven Levy remembers living in Philadelphia in the 19 70s and renting an apartment from a man named J. Presper Eckert Jr. “It was only when I became a technology writer some years later that I realize d that my landlord had invented the computer.”\n\n \n\n \n vi deo not available https://www.youtube.com/watch?v=G8R6li54R20\n \n\n \n  \n \n\n \n In the early 1940s\, Eckert had been a gr aduate student in the school of engineering who became the ENIAC’s chief engineer. A professor had proposed electronic calculations for munitions trajectories to help the American military during World War II.\n\n Levy c alls it “a breathtaking enterprise. The original cost estimate of $150\, 000 would rise to $400\,000. Weighing in at 30 tons\, the U-shaped constru ct filled a 1\,500-square-foot room. Its 40 cabinets\, each of them nine f eet high\, were packed with 18\,000 vacuum tubes\, 10\,000 capacitors\, 6\ ,000 switches and 1\,500 relays… Two 20-horsepower blowers exhaled cool air so that ENIAC wouldn’t melt down.”\n\n By the time they’d finish ed building it — World War II was over.\n\n But there was still work to do. The Atomic Heritage Foundation site reports that ENIAC was used to he lp perform the engineering calculations for the world’s first hydrogen bomb (along with two other more-recently developed computers). “It took sixty straight days of processing\, all through the summer of 1951.”\n\n Levy cites an Army press release describing ENIAC as a “mathematical ro bot” that “frees scientific thought from the drudgery of lengthy calcu lating work.”\n\n A recent documentary called The Computers reminds mo dern-day viewers that the ENIAC’s original programmers were all women — Kay McNulty\, Betty Jennings\, Betty Snyder\, Marlyn Wescoff\, F ran Bilas and Ruth Lichterman.\n\n \n\n \n \n \n\n \n There’s now also a site called the ENIAC Programmers Project that sha res a brief overview of the documentary with more information. During Worl d War II\, the U.S. military had put together a team of nearly 100 women\, trained in mathematics\, who were calculating complex ballistic-trajector y equations. Six of them were selected to program the ENIAC.\n\n Back in 1 996\, the IEEE Annals of the History of Computing ran a profile of “The Women of ENIAC\,” interviewing 10 of the women who’d worked with the computer during its 10-year run.\n\n The poster for the documentary descr ibes them as “six women lost from history who created technologies that changed our world.”\n\n The ENIAC was eventually left behind by ever-fas ter and ever-cheaper computers. “By the time it was decommissioned in 19 55 it had been used for research on the design of wind tunnels\, random nu mber generators\, and weather prediction\,” remembers an ENIAC web page at Oak Ridge National Laboratory.\n\n And even though ENIAC was decommissi oned in 1955\, 50 years later it was reassembled for a humble ceremony in Philadelphia\, Levy remembers.\n\n “Vice President Al Gore threw a switc h and the remaining pieces clattered out the answer to an addition problem .”\n\n According to Levy\, the ENIAC’s chief engineer later groused “How would you like to have most of your life’s work end up on a squar e centimeter of silicon?” But Levy sees another way to look at it. “[T ]he question could easily have been put another way: How would you like to have invented the machine that changed the course of civilization?”\n\n Yet legacies aside\, it also seems like it was a real thrill just to have been a part of the work itself.\n\n “I’ve never seen been in as excit ing an environment\,” remembers Jean Jennings Bartik in the film. “We knew we were pushing back frontiers.”\n\n And more than 60 years later\, she also still remembered that the ENIAC computer “was a son-of-a-bitch to program.”\n\n \n\n \n  \n \n\n \n The Women of ENIAC\n \n\n \n https://web.archive.org/web/20160304052225/http: //www.eg.bucknell.edu/~csci203/2012-fall/hw/hw06/assets/womenOfENIAC.pdf\n \n\n \n                \n \n \n \n \n\n \ n \n \n  \n \n \n\n \n \n  \n \n \n \n\n\n\n \n  \n \n\n DTSTART;VALUE=DATE:20250305 RRULE:FREQ=YEARLY;INTERVAL=1 END:VEVENT END:VCALENDAR