23. Ada to Charles Babbage, July 30, 1843.
24. Ada to Lady Byron, Jan. 11, 1841.
25. Toole, Ada, the Enchantress of Numbers, 136.
26. Ada to Lady Byron, Feb. 6, 1841; Stein, Ada, 87.
27. Stein, Ada, 38.
28. Harry Wilmot Buxton and Anthony Hyman, Memoir of the Life and Labours of the Late Charles Babbage (ca. 1872; reprinted by Charles Babbage Institute/MIT Press, 1988), 46.
29. Martin Campbell Kelly and William Aspray, Computer: A History of the Information Machine (Westview, 2009), 6.
30. Swade, The Difference Engine, 42; Bernstein, The Analytical Engine, 46 and passim.
31. James Essinger, Jacquard’s Web (Oxford, 2004), 23.
32. Ada to Charles Babbage, Feb. 16, 1840.
33. Ada to Charles Babbage, Jan. 12, 1841.
34. Charles Babbage, Passages from the Life of a Philosopher (Longman Green, 1864), 136.
35. Luigi Menabrea, with notes upon the memoir by the translator, Ada, Countess of Lovelace, “Sketch of the Analytical Engine, Invented by Charles Babbage,” Oct. 1842, http://www.fourmilab.ch/babbage/sketch.html.
36. Babbage, Passages from the Life of a Philosopher, 136; John Füegi and Jo Francis, “Lovelace & Babbage and the Creation of the 1843 ‘Notes,’ ” Annals of the History of Computing, Oct. 2003.
37. All quotes from Menabrea and Lovelace’s notes are from Menabrea, “Sketch of the Analytical Engine.”
38. Charles Babbage to Ada, 1843, in Toole, Ada, the Enchantress of Numbers, 197.
39. Spoken in the film Ada Byron Lovelace: To Dream Tomorrow, directed and produced by John Füegi and Jo Francis (Flare Productions, 2003); also, Füegi and Francis, “Lovelace & Babbage.”
40. Ada to Charles Babbage, July 5, 1843.
41. Ada to Charles Babbage, July 2, 1843.
42. Ada to Charles Babbage, Aug. 6, 1843; Woolley, The Bride of Science, 278; Stein, Ada, 114.
43. Ada to Lady Byron, Aug. 8, 1843.
44. Ada to Charles Babbage, Aug. 14, 1843.
45. Ada to Charles Babbage, Aug. 14, 1843.
46. Ada to Charles Babbage, Aug. 14, 1843.
47. Ada to Lady Lovelace, Aug. 15, 1843.
48. Stein, Ada, 120.
49. Ada to Lady Byron, Aug. 22, 1843.
50. Ada to Robert Noel, Aug. 9, 1843.
CHAPTER TWO: THE COMPUTER
1. Andrew Hodges, Alan Turing : The Enigma (Simon & Schuster, 1983; locations refer to the Kindle “Centenary Edition”), 439. In addition to the sources cited below, this section draws on Hodges’s biography and his website, http://www.turing.org.uk/; the correspondence and documents in the Turing Archive, http://www.turingarchive.org/; David Leavitt, The Man Who Knew Too Much (Atlas Books, 2006); S. Barry Cooper and Jan van Leeuwen, Alan Turing : His Work and Impact (Elsevier, 2013); Sara Turing, Alan M. Turing (Cambridge, 1959; locations refer to the Kindle “Centenary Edition,” with an afterword by John F. Turing, published in 2012); Simon Lavington, editor, Alan Turing and His Contemporaries (BCS, 2012).
2. John Turing in Sara Turing, Alan M. Turing, 146.
3. Hodges, Alan Turing, 590.
4. Sara Turing, Alan M. Turing, 56.
5. Hodges, Alan Turing, 1875.
6. Alan Turing to Sara Turing, Feb. 16, 1930, Turing archive; Sara Turing, Alan M. Turing, 25.
7. Hodges, Alan Turing, 2144.
8. Hodges, Alan Turing, 2972.
9. Alan Turing, “On Computable Numbers,” Proceedings of the London Mathematical Society, read on Nov. 12, 1936.
10. Alan Turing, “On Computable Numbers,” 241.
11. Max Newman to Alonzo Church, May 31, 1936, in Hodges, Alan Turing, 3439; Alan Turing to Sara Turing, May 29, 1936, Turing Archive.
12. Alan Turing to Sara Turing, Feb. 11 and Feb. 22, 1937, Turing Archive; Alonzo Church, “Review of A. M. Turing’s ‘On computable numbers,’ ” Journal of Symbolic Logic, 1937.
13. This Shannon section draws on Jon Gertner, The Idea Factory: Bell Labs and the Great Age of American Innovation (Penguin, 2012; locations refer to the Kindle edition), chapter 7; M. Mitchell Waldrop, “Claude Shannon: Reluctant Father of the Digital Age,” MIT Technology Review, July 2001; Graham Collins, “Claude E. Shannon: Founder of Information Theory,” Scientific American, Oct. 2012; James Gleick, The Information (Pantheon, 2011), chapter 7.
14. Peter Galison, Image and Logic (University of Chicago, 1997), 781.
15. Claude Shannon, “A Symbolic Analysis of Relay and Switching Circuits,” Transactions of the American Institute of Electrical Engineers, Dec. 1938. For a clear explanation, see Daniel Hillis, The Pattern on the Stone (Perseus, 1998), 2–10.
16. Paul Ceruzzi, Reckoners: The Prehistory of the Digital Computer (Greenwood, 1983), 79. See also Computer History Museum, “George Stibitz,” http://www.computerhistory.org/revolution/birth-of-the-computer/4/85.
17. Howard Aiken oral history, conducted by Henry Tropp and I. Bernard Cohen, Smithsonian Institution, Feb. 1973.
18. Howard Aiken, “Proposed Automatic Calculating Machine,” IEEE Spectrum, Aug. 1964; Cassie Ferguson, “Howard Aiken: Makin’ a Computer Wonder,” Harvard Gazette, Apr. 9, 1998.
19. I. Bernard Cohen, Howard Aiken: Portrait of a Computer Pioneer (MIT, 1999), 9.
20. Kurt Beyer, Grace Hopper and the Invention of the Information Age (MIT, 2009), 75.
21. Cohen, Howard Aiken, 115.
22. Cohen, Howard Aiken, 98 and passim.
23. Beyer, Grace Hopper, 80.
24. Ceruzzi, Reckoners, 65.
25. Horst Zuse (son), The Life and Work of Konrad Zuse, http://www.horst-zuse.homepage.t-online.de/Konrad_Zuse_index_english_html/biography.html.
26. Konrad Zuse archive, http://www.zib.de/zuse/home.php/Main/KonradZuse; Ceruzzi, Reckoners, 26.
27. Horst Zuse, The Life and Work of Konrad Zuse, part 4; Ceruzzi, Reckoners, 28.
28. The story of John Atanasoff and the controversy over the credit he deserves has led to some impassioned writings. A historical and legal battle pitted him against the creators of ENIAC, John Mauchly and Presper Eckert. The four main books about Atanasoff are all written by people who sought to take his side in this dispute. Alice Burks, Who Invented the Computer? (Prometheus, 2003; locations refer to the Kindle edition), is partly based on the documents of the legal battle. Alice Burks and Arthur Burks, The First Electronic Computer: The Atanasoff Story (University of Michigan, 1988) is an earlier, more technical book; Arthur Burks was an engineer on the ENIAC team who ended up being critical of Eckert and Mauchly. Clark Mollenhoff, Atanasoff: Forgotten Father of the Computer (Iowa State, 1988) was written by a Pulitzer Prize–winning reporter who was the Washington bureau chief of the Des Moines Register and after hearing of Atanasoff sought to resurrect him from being forgotten by history. Jane Smiley, The Man Who Invented the Computer (Doubleday, 2010) is by the acclaimed novelist who immersed herself in computer history and became an advocate for Atanasoff. For the personal background and involvement of Alice and Arthur Burks, see their “Memoir of the 1940s,” Michigan Quarterly Review, Spring 1997, http://hdl.handle.net/2027/spo.act2080.0036.201. This section also draws on Allan Mackintosh, “Dr. Atanasoff’s Computer,” Scientific American, Aug. 1988; Jean Berry, “Clifford Edward Berry: His Role in Early Computers,” Annals of the History of Computing, July 1986; William Broad, “Who Should Get the Glory for Inventing the Computer?” New York Times, Mar. 22, 1983.
29. John Atanasoff, “Advent of Electronic Digital Computing,” Annals of the History of Computing, July 1984, 234.
30. Atanasoff, “Advent of Electronic Digital Computing,” 238.
31. Atanasoff, “Advent of Electronic Digital Computing,” 243.
32. Katherine Davis Fishman, The Computer Establishment (Harper and Row, 1981), 22.
33. Atanasoff testimony, Honeywell v. Sperry Rand, June 15, 1971, transcript p. 1700, in Burks, Who Invented the Computer?, 1144. The archives for the trial are at the University of Pennsylvania, http://www.arch
ives.upenn.edu/faids/upd/eniactrial/upd8_10.html, and at the Charles Babbage Institute of the University of Minnesota, http://discover.lib.umn.edu/cgi/f/findaid/findaid-idx?c=umfa;cc=umfa;rgn=main;view=text;didno=cbi00001.
34. Atanasoff testimony, transcript p. 1703.
35. Atanasoff, “Advent of Electronic Digital Computing,” 244.
36. John Atanasoff, “Computing Machine for the Solution of Large Systems of Linear Algebraic Equations,” 1940, available online from Iowa State, http://jva.cs.iastate.edu/img/Computing%20machine.pdf. For detailed analysis, see Burks and Burks, The First Electronic Computer, 7 and passim.
37. Robert Stewart, “The End of the ABC,” Annals of the History of Computing, July 1984; Mollenhoff, Atanasoff, 73.
38. This section draws on John Mauchly oral history, conducted by Henry Tropp, Jan. 10, 1973, Smithsonian Institution; John Mauchly oral history, conducted by Nancy Stern, May 6, 1977, American Institute of Physics (AIP); Scott McCartney, ENIAC (Walker, 1999); Herman Goldstine, The Computer from Pascal to von Neumann (Princeton, 1972; locations refer to Kindle edition); Kathleen Mauchly, “John Mauchly’s Early Years,” Annals of the History of Computing, Apr. 1984; David Ritchie, The Computer Pioneers (Simon & Schuster, 1986); Bill Mauchly and others, “The ENIAC” website, http://the-eniac.com/first/; Howard Rheingold, Tools for Thought (MIT, 2000); Joel Shurkin, Engines of the Mind: A History of the Computer (Washington Square Press, 1984).
39. John Costello, “The Twig Is Bent: The Early Life of John Mauchly,” IEEE Annals of the History of Computing, 1996.
40. Mauchly oral history, AIP.
41. Costello, “The Twig Is Bent.”
42. McCartney, ENIAC, 82.
43. Kay McNulty Mauchly Antonelli, “The Kathleen McNulty Mauchly Antonelli Story,” Mar. 26, 2004, ENIAC website, https://sites.google.com/a/opgate.com/eniac/Home/kay-mcnulty-mauchly-antonelli; McCartney, ENIAC, 32.
44. Ritchie, The Computer Pioneers, 129; Rheingold, Tools for Thought, 80.
45. McCartney, ENIAC, 34.
46. Kathleen Mauchly, “John Mauchly’s Early Years.”
47. McCartney, ENIAC, 36.
48. Kathleen Mauchly, “John Mauchly’s Early Years.”
49. John Mauchly to H. Helm Clayton, Nov. 15, 1940.
50. John Mauchly to John de Wire, Dec. 4, 1940; Kathleen Mauchly, “John Mauchly’s Early Years.”
51. Mauchly to Atanasoff, Jan. 19, 1941; Atanasoff to Mauchly, Jan. 23, 1941; Mauchly oral history, Smithsonian; Burks, Who Invented the Computer?, 668.
52. The battle over what happened was fought out in the Annals of the History of Computing, with multiple articles, comments, and bitter letters. This section and that on the legal battle, below, derive from them. They include Arthur Burks and Alice Burks, “The ENIAC: First General-Purpose Electronic Computer,” with comments by John Atanasoff, J. Presper Eckert, Kathleen R. Mauchly, and Konrad Zuse, and a response by Burks and Burks, Annals of the History of Computing, Oct. 1981, 310–99 (more than eighty pages of this issue were devoted to the assertions and rebuttals, prompting some discomfort on the part of the editors); Kathleen Mauchly, “John Mauchly’s Early Years,” Annals of the History of Computing, Apr. 1984; John Mauchly, “Mauchly: Unpublished Remarks,” with an afterword by Arthur Burks and Alice Burks, Annals of the History of Computing, July 1982; Arthur Burks, “Who Invented the General Purpose Computer?” talk at the University of Michigan, Apr. 2, 1974; James McNulty, letter to the editor, Datamation, June 1980.
53. Lura Meeks Atanasoff testimony, Sperry v. Honeywell; Burks, Who Invented the Computer?, 1445.
54. Mollenhoff, Atanasoff, 114.
55. Mauchly oral history, Smithsonian; John Mauchly, “Fireside Chat,” Nov. 13, 1973, Annals of the History of Computing, July 1982.
56. Ritchie, The Computer Pioneers, 142.
57. Mauchly oral history, Smithsonian.
58. John Mauchly testimony, Sperry v. Honeywell ; Burks, Who Invented the Computer?, 429.
59. John Mauchly to John Atanasoff, Sept. 30, 1941, Sperry v. Honeywell trial records.
60. Atanasoff to Mauchly, Oct. 7, 1941, Sperry v. Honeywell trial records.
61. In addition to the sources cited below, this section draws from Peter Eckstein, “Presper Eckert,” Annals of the History of Computing, Spring 1996; J. Presper Eckert oral history, conducted by Nancy Stern, Oct. 28, 1977, Charles Babbage Institute, University of Minnesota; Nancy Stern, From ENIAC to UNIVAC (Digital Press, 1981); J. Presper Eckert, “Thoughts on the History of Computing,” Computer, Dec. 1976; J. Presper Eckert, “The ENIAC,” John Mauchly, “The ENIAC,” and Arthur W. Burks, “From ENIAC to the Stored Program Computer,” all in Nicholas Metropolis et al., editors, A History of Computing in the Twentieth Century (Academic Press, 1980); Alexander Randall, “A Lost Interview with Presper Eckert,” Computerworld, Feb. 4, 2006.
62. Eckert oral history, Charles Babbage Institute.
63. Eckstein, “Presper Eckert.”
64. Ritchie, The Computer Pioneers, 148.
65. Eckert oral history, Charles Babbage Institute.
66. John W. Mauchly, “The Use of High Speed Vacuum Tube Devices for Calculating,” 1942, in Brian Randell, editor, The Origins of Digital Computers: Selected Papers (Springer-Verlag, 1973), 329. See also John G. Brainerd, “Genesis of the ENIAC,” Technology and Culture, July 1976, 482.
67. Mauchly oral history, Smithsonian; Goldstine, The Computer from Pascal to von Neumann, 3169; McCartney, ENIAC, 61.
68. Burks, Who Invented the Computer?, 71.
69. McCartney, ENIAC, 89.
70. Eckert oral history, Charles Babbage Institute.
71. Eckert oral history, Charles Babbage Institute.
72. Eckert oral history, Charles Babbage Institute; Randall, “A Lost Interview with Presper Eckert.”
73. Hodges, Alan Turing, 3628.
74. In addition to the Hodges biography, Alan Turing, this section draws on B. Jack Copeland, Colossus: The Secrets of Bletchley Park’s Codebreaking Computers (Oxford, 2006); I. J. Good, “Early Work on Computers at Bletchley,” Annals of the History of Computing, July 1979; Tommy Flowers, “The Design of Colossus,” Annals of the History of Computing, July 1983; Simon Lavington, editor, Alan Turing and His Contemporaries (BCS, 2012); Sinclair McKay, The Secret Life of Bletchley Park: The History of the Wartime Codebreaking Centre by the Men and Women Who Were There (Aurum Press, 2010); and my visit to Bletchley Park and the scholars, tour guides, displays, and material available there.
75. Randall, “A Lost Interview with Presper Eckert.”
76. The archives for the Honeywell v. Sperry Rand trial. See also Charles E. McTiernan, “The ENIAC Patent,” Annals of the History of Computing, Apr. 1998.
77. Judge Earl Richard Larson decision, Honeywell v. Sperry Rand.
78. Randall, “A Lost Interview with Presper Eckert.”
CHAPTER THREE: PROGRAMMING
1. Alan Turing, “Intelligent Machinery,” National Physical Laboratory report, July 1948, available at http://www.AlanTuring.net/intelligent_machinery.
2. In addition to the sources cited below, this section draws from Kurt Beyer, Grace Hopper and the Invention of the Information Age (MIT, 2009), and the following trove of Grace Hopper oral histories: Smithsonian (five sessions), July 1968, Nov. 1968, Jan. 7, 1969, Feb. 4, 1969, July 5, 1972; the Computer History Museum, Dec. 1980; Grace Hopper interview, Sept. 1982, Women in Federal Government oral history project, Radcliffe Institute, Harvard.
3. Kurt Beyer mistakenly calls her the first to get a math doctorate from Yale. Charlotte Barnum was the first in 1895, and there were ten before Hopper. See Judy Green and Jeanne LaDuke, Pioneering Women in American Mathematics: The pre-1940 PhDs (American Mathematical Society, 2009), 53; Beyer, Grace Hopper, 25 and 26.
4. Hopper oral history, Smithsonian, July 5, 1972.
5. Hopper oral history, Smithsonian, July 1968; Rosario Rausa, “In Profile, Grace Murray Hopper,” Naval History, Fall 1992.
6. Hopper oral hist
ories (she told the same story), Computer History Museum and Smithsonian, July 5, 1972.
7. The Staff of the Harvard Computation Library [Grace Hopper and Howard Aiken], A Manual of Operation for the Automatic Sequence Controlled Calculator (Harvard, 1946).
8. Grace Hopper oral history, Computer History Museum.
9. Beyer, Grace Hopper, 130.
10. Beyer, Grace Hopper, 135.
11. Richard Bloch oral history, Charles Babbage Institute, University of Minnesota.
12. Beyer, Grace Hopper, 53.
13. Grace Hopper and Richard Bloch panel discussion comments, Aug. 30, 1967, in Henry S. Tropp, “The 20th Anniversary Meeting of the Association for Computing Machinery,” IEEE Annals, July 1987.
14. Beyer, Grace Hopper, 5.
15. Hopper oral history, Smithsonian, July 5, 1972.
16. Howard Aiken oral history, conducted by Henry Tropp and I. Bernard Cohen, Smithsonian Institution, Feb. 1973.
17. Grace Hopper and John Mauchly, “Influence of Programming Techniques on the Design of Computers,” Proceedings of the IRE, Oct. 1953.
18. Harvard computer log, Sept. 9, 1947, http://www.history.navy.mil/photos/images/h96000/h96566k.jpg.
19. Grace Hopper oral history, Smithsonian, Nov. 1968.
20. The Moore School Lectures, Charles Babbage Institute, reprint (MIT Press, 1985).
21. Hopper oral history, Smithsonian, Nov. 1968.
22. In addition to the sources cited below, this section draws on Jean Jennings Bartik, Pioneer Programmer (Truman State, 2013; locations refer to the Kindle edition); Jean Bartik oral history, conducted by Gardner Hendrie, Computer History Museum, July 1, 2008; Jean Bartik oral history, conducted by Janet Abbate, IEEE Global History Network, Aug. 3, 2001; Steve Lohr, “Jean Bartik, Software Pioneer, Dies at 86,” New York Times, Apr. 7, 2011; Jennifer Light, “When Computers Were Women,” Technology and Culture, July 1999.
23. Jordynn Jack, Science on the Home Front: American Women Scientists in World War II (University of Illinois, 2009), 3.
24. Jennings Bartik, Pioneer Programmer, 1282.
25. W. Barkley Fritz, “The Women of ENIAC,” IEEE Annals of the History of Computing, Fall 1996.
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