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The Z3 was a German electromechanical computer designed by Konrad Zuse in 1935, and completed in 1941. It was the world's first working programmable, fully automatic digital computer.^[1] The Z3 was built with 2,600 relays, implementing a 22-bit word length that operated at a clock frequency of about 5–10 Hz.^[2] Program code was stored on punched film. Initial values were entered manually.^[3]^[4]^[5]^: 32–37

The Z3 was completed in Berlin in 1941. It was not considered vital, so it was never put into everyday operation.^[3]^[4]^[6]^[5]^{: 30, 38–39}^[a] Based on the work of the German aerodynamics engineer Hans Georg Küssner (known for the Küssner effect), a "Program to Compute a Complex Matrix"^[b] was written and used to solve wing flutter problems. Zuse asked the German government for funding to replace the relays with fully electronic switches, but funding was denied during World War II since such development was deemed "not war-important".^[10]^: 148

The original Z3 was destroyed on 21 December 1943 during an Allied bombardment of Berlin. That Z3 was originally called V3 (Versuchsmodell 3 or Experimental Model 3) but was renamed so that it would not be confused with Germany's V-weapons.^[11] A fully functioning replica was built in 1961 by Zuse's company, Zuse KG, which is now on permanent display at Deutsches Museum in Munich.^[5]^: 30

The Z3 was demonstrated in 1998 to be, in principle, Turing-complete.^[12] However, because it lacked conditional branching, the Z3 only meets this definition by speculatively computing all possible outcomes of a calculation.

Thanks to this machine and its predecessors, Konrad Zuse has often been suggested as the inventor of the computer.^[13]^[14]^[15]^[16]

Design and development

Zuse designed the Z1 in 1935 to 1936 and built it from 1936 to 1938. The Z1 was wholly mechanical and only worked for a few minutes at a time at most. Helmut Schreyer advised Zuse to use a different technology. As a doctoral student at the Berlin Institute of Technology in 1937 he worked on the implementation of Boolean operations and (in today's terminology) flip-flops on the basis of vacuum tubes. In 1938 Schreyer demonstrated a circuit on this basis to a small audience, and explained his vision of an electronic computing machine – but since the largest operational electronic devices contained far fewer tubes this was considered practically infeasible.^[17] In that year when presenting the plan for a computer with 2,000 electron tubes, Zuse and Schreyer, who was an assistant at Wilhelm Stäblein's [de] Telecommunication Institute at the Technical University of Berlin, were discouraged by members of the institute who knew about the problems with electron tube technology.^[18] Zuse later recalled: "They smiled at us in 1939, when we wanted to build electronic machines ... We said: The electronic machine is great, but first the components have to be developed."^[19] In 1940 Zuse and Schreyer managed to arrange a meeting at the Oberkommando der Wehrmacht (OKW) to discuss a potential project for developing an electronic computer, but when they estimated a duration of two or three years, the proposal was rejected.^[20]

Zuse decided to implement the next design based on relays. The realization of the Z2 was helped financially by Kurt Pannke, who manufactured small calculating machines. The Z2 was completed and presented to an audience of the Deutsche Versuchsanstalt für Luftfahrt ("German Laboratory for Aviation") in 1940 in Berlin-Adlershof. Zuse was lucky – this presentation was one of the few instances where the Z2 actually worked and could convince the DVL to partly finance the next design.^[17]

Improving on the basic Z2 machine, he built the Z3 in 1941, which was a highly secret project of the German government.^[21] Joseph Jennissen (1905–1977),^[22] member of the "Research-Leadership" (Forschungsführung) in the Reich Air Ministry^[23] acted as a government supervisor for orders of the ministry to Zuse's company ZUSE Apparatebau.^[24] A further intermediary between Zuse and the Reich Air Ministry was the aerodynamicist Herbert A. Wagner.^[25]

The Z3 was completed in 1941 and was faster and far more reliable than the Z1 and Z2. The Z3 floating-point arithmetic was improved over that of the Z1 in that it implemented exception handling "using just a few relays", the exceptional values (plus infinity, minus infinity and undefined) could be generated and passed through operations. The Z3 stored its program on an external punched tape, thus no rewiring was necessary to change programs. However, it did not have conditional branching found in later universal computers.^[26]^: 7

On 12 May 1941 the Z3 was presented to an audience of scientists including the professors Alfred Teichmann and Curt Schmieden^[27] of the Deutsche Versuchsanstalt für Luftfahrt ("German Laboratory for Aviation") in Berlin,^[28] today known as the German Aerospace Center in Cologne.^[29]

Zuse moved on to the Z4 design, which he completed in a bunker in the Harz mountains, alongside Wernher von Braun's ballistic missile development. When World War II ended, Zuse retreated to Hinterstein in the Alps with the Z4, where he remained for several years.^[30]

Instruction set

The Z3 operated as a stack machine with a stack of two registers, R1 and R2. The first load operation in a program would load the contents of a memory location into R1; the next load operation would load the contents of a memory location into R2. Arithmetic instructions would operate on the contents of R1 and R2, leaving the result in R1, and clearing R2; the next load operation would load into R2. A store operation would store the contents of R1 into a memory location, and clear R1; the next load operation would load the contents of a memory location into R1.^[26]^: 8

A read keyboard operation would read a number from the keyboard into R1 and clear R2. A display instruction would display the contents of R1 and clear R2; the next load instruction would load into R2.^[26]^: 8

Z3 as a universal Turing machine

It was possible to construct loops on the Z3, but there was no conditional branch instruction. Nevertheless, the Z3 was Turing-complete – how to implement a universal Turing machine on the Z3 was shown in 1998 by Raúl Rojas. He proposed that the tape program would have to be long enough to execute every possible path through both sides of every branch. It would compute all possible answers, but the unneeded results would be canceled out (a kind of speculative execution). Rojas concludes, "We can therefore say that, from an abstract theoretical perspective, the computing model of the Z3 is equivalent to the computing model of today's computers. From a practical perspective, and in the way the Z3 was really programmed, it was not equivalent to modern computers."^[12]

This seeming limitation belies the fact that the Z3 provided a practical instruction set for the typical engineering applications of the 1940s. Mindful of the existing hardware restrictions, Zuse's main goal at the time was to have a workable device to facilitate his work as a civil engineer.^[31]

Relation to other work

The success of Zuse's Z3 is often attributed to its use of the simple binary system.^[5]^: 21 This was invented roughly three centuries earlier by Gottfried Leibniz; Boole later used it to develop his Boolean algebra. Zuse was inspired by Hilbert's and Ackermann's book on elementary mathematical logic Principles of Mathematical Logic.^[18] In 1937, Claude Shannon introduced the idea of mapping Boolean algebra onto electronic relays in a seminal work on digital circuit design. Zuse, however, did not know of Shannon's work and developed the groundwork independently^[10]^: 149 for his first computer Z1, which he designed and built from 1935 to 1938.

Zuse's coworker Helmut Schreyer built an electronic digital experimental model of a computer using 100 vacuum tubes^[32] in 1942, but it was lost at the end of the war.

An analog computer was built by the rocket scientist Helmut Hölzer in 1942 at the Peenemünde Army Research Center to simulate^[33]^[34]^[35] V-2 rocket trajectories.^[36]^[37]

The Tommy Flowers-built Colossus (1943)^[38] and the Atanasoff–Berry Computer (1942) used thermionic valves (vacuum tubes) and binary representation of numbers. Programming was by means of re-plugging patch panels and setting switches.^{[citation needed]}

The ENIAC computer, completed after the war, used vacuum tubes to implement switches and used decimal representation for numbers. Until 1948 programming was, as with Colossus, by patch leads and switches.^[39]^[40]

The Manchester Baby of 1948 along with the Manchester Mark 1 and EDSAC both of 1949 were the world's earliest working computers that stored program instructions and data in the same space. In this they implemented the stored-program concept which is frequently (but erroneously) attributed to a 1945 paper by John von Neumann and colleagues.^[41]^[42] Von Neumann is said to have given due credit to Alan Turing,^[43] and the concept had actually been mentioned earlier by Konrad Zuse himself, in a 1936 patent application (that was rejected).^[44]^[45] Konrad Zuse himself remembered in his memoirs: "During the war it would have barely been possible to build efficient stored program devices anyway."^[46] and Friedrich L. Bauer wrote: "His visionary ideas (live programs) which were only to be published years afterwards aimed at the right practical direction but were never implemented by him."^[47]

Specifications

Average calculation speed: addition – 0.8 seconds, multiplication – 3 seconds^[2]
Arithmetic unit: Binary floating-point, 22-bit, add, subtract, multiply, divide, square root^[2]
Data memory: 64 words with a length of 22 bits^[2]
Program memory: Punched celluloid tape^[2]
Input: Decimal floating-point numbers^[2]
Output: Decimal floating-point numbers^[2]
Input and Output was facilitated by a terminal, with a special keyboard for input and a row of lamps to show results^[17]
Elements: Around 2,000 relays (1,400 for the memory)^[17]
Frequency: 5–10 hertz^[2]
Power consumption: Around 4,000 watts^[2]
Weight: Around 1 tonne (2,200 lb)^[2]

Modern reconstructions

A modern reconstruction directed by Raúl Rojas and Horst Zuse started in 1997 and finished in 2003. It is now in the Konrad Zuse Museum in Hünfeld, Germany.^[48]^[49] Memory was halved to 32 words. Power consumption is about 400 W, and weight is about 30 kilograms (66 lb).^[50]

In 2008, Horst Zuse started a reconstruction of the Z3 by himself.^[51] It was presented in 2010 in the Konrad Zuse Museum in Hünfeld.^[52]^[53]

Notes

^ It could solve problems like systems of linear equations and their determinants, quadratic equations and Eigenvalues (for wing flutter).^[7]^[8]
^ German: Programm für die Berechnung einer komplexen Matrix^[9]

References

^ "A Computer Pioneer Rediscovered, 50 Years On". The New York Times. 1994-04-20. Archived from the original on 2016-11-04.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Morelli, Marcello (2001). Dalle calcolatrici ai computer degli anni Cinquanta. FrancoAngeli. p. 177. ISBN 978-8-84642879-0. Retrieved 2014-08-05.
^ ^a ^b Weiss, E. (Summer 1996). "Konrad Zuse Obituary". IEEE Annals of the History of Computing. 18 (2): 3–4. doi:10.1109/mahc.1996.489747. ISSN 1058-6180.
^ ^a ^b Borchers, Detlef (2016-05-12). "Vor 75 Jahren: Computer Z3 wird vorgeführt" [75 years ago: Computer Z3 is demonstrated]. heise online (in German). Retrieved 2018-05-13.
^ ^a ^b ^c ^d Ceruzzi, Paul E. (1983). "2. Computers in Germany". Reckoners: The Prehistory of The Digital Computer, From Relays to the Stored Program Concept, 1935–1945. Greenwood Press. ISBN 0-313-23382-9. Retrieved 2018-11-03.
^ Zuse, Konrad (2013-03-09). The Computer – My Life. Springer Science & Business Media. p. 64. ISBN 978-3-66202931-2.
^ Slater, Robert (1989). Portraits in Silicon. MIT Press. pp. 46–47. ISBN 978-0-26269131-4.
^ Schindler, Max J. (1990). Computer-aided software design: build quality software with CASE. Wiley. p. 419. ISBN 9780471506508.
^ Hellige, Hans Dieter, ed. (2004). Geschichten der Informatik. Visionen, Paradigmen, Leitmotive (in German). Berlin, Germany: Springer. ISBN 978-3-540-00217-8.
^ ^a ^b Hohn, Hans-Willy (1998). Kognitive Strukturen und Steuerungsprobleme der Forschung. Kernphysik und Informatik im Vergleich (in German). Schriften des Max-Planck-Instituts für Gesellschaftsforschung Köln. ISBN 978-3-593-36102-4.
^ "Z3 Computer (1938–1941)". www.computermuseum.li. Archived from the original on 2008-06-17.
^ ^a ^b Rojas, Raúl (1997-09-05). "How to make Zuse's Z3 a universal computer" (PDF). IEEE Annals of the History of Computing. 20 (3) (published July–September 1998): 51–54. doi:10.1109/85.707574.
^ "Konrad Zuse Biography". RTD Net. From various sides Konrad Zuse was awarded with the title "Inventor of the computer".
^ "Konrad Zuse". The German Way. The Konrad-Zuse-Zentrum für Informationstechnik Berlin (ZIB), founded in 1986, is a working memorial to the German inventor of the computer.
^ von Leszczynski, Ulrike (2010-06-27). "Z like Zuse: German inventor of the computer". Monsters & Critics. Archived from the original on 2013-05-22. he [Zuse] built the world's first computer in Berlin
^ Bellis, Mary (2017-07-31). "Konrad Zuse and the Invention of the Modern Computer". Zuse earned the semi-official title of "inventor of the modern computer" for his series of automatic calculators, which he invented to help him with his lengthy engineering calculations.
^ ^a ^b ^c ^d Lippe, Wolfram. Kapitel 14 – Die ersten programmierbaren Rechner [The first programmable computers] (PDF) (in German). doi:10.1007/978-3-642-36193-7_6. Archived from the original (PDF) on 2011-07-19. Retrieved 2010-06-21.
^ ^a ^b Hellige, Hans Dieter, ed. (2004). Geschichten der Informatik. Visionen, Paradigmen, Leitmotive (in German). Berlin, Germany: Springer. pp. 113, 152. ISBN 978-3-540-00217-8.
^ Hellige, Hans Dieter, ed. (2004). Geschichten der Informatik. Visionen, Paradigmen, Leitmotive (in German). Berlin, Germany: Springer. p. 102. ISBN 978-3-540-00217-8. Man hat 1939 über uns gelächelt, als wir elektronische Geräte bauen wollten. ... Wir sagten uns damals: Die elektronische Maschine ist wunderbar, aber erst müssen ihre Bauelemente entwickelt werden.
^ Hellige, Hans Dieter, ed. (2004). Geschichten der Informatik. Visionen, Paradigmen, Leitmotive (in German). Berlin, Germany: Springer. p. 115. ISBN 978-3-540-00217-8.
^ "New perspectives, computer concepts", June Jamrich Parsons, Dan Oja. Cengage Learning, 2007. ISBN 978-1-4239-0610-0, ISBN 978-1-4239-0610-0. Retrieved 2010-03-14.
^ Alexander Kauther, Paul Wirtz: Der Einzelkämpfer Dorner. Grin Verlag Gmbh, 2013, ISBN 3-656-04860-6
^ Helmut Maier: Forschung als Waffe, Wallstein Verlag, 2007, ISBN 3-8353-0109-8, p. 847
^ "1977-compilation by Zuse of people in contact to his computers from 1935 to 1945" (in German). Archived from the original on 2011-09-28.
^ Herbert Bruderer, ETH Zurich. "Konrad Zuse und die ETH Zürich" (PDF) (in German). Retrieved 2011-10-26.
^ ^a ^b ^c Rojas, Raúl (April–June 1997). "Konrad Zuse's Legacy: The Architecture of the Z1 and Z3" (PDF). IEEE Annals of the History of Computing. 19 (2): 5–15. doi:10.1109/85.586067.
^ "An einem 12. Mai" (in German). Deutsches Historisches Museum (German Historical Museum).
^ "Technische Universität Berlin – Rechenhilfe für Ingenieure" (in German). Technical University of Berlin. Archived from the original on 2009-02-13.
^ "Die Geschichte des DLR-Standorts Berlin-Adlershof" (in German). German Aerospace Center.
^ Campbell-Kelly, Martin (1995-12-21). "OBITUARY: Konrad Zuse". The Independent. Archived from the original on 2022-05-07. Retrieved 2021-05-11.
^ Zuse, Konrad (1987-10-02). "My First Computer and First Thoughts About Data Processing". history.computer.org. Computer Pioneers – Konrad Zuse. Retrieved 2018-05-14. Search for 1941; ["Computer Design-Past, Present, Future," talk in Lund/Sweden, 1987-10-02, previously unpublished.]
^ "Helmut Schreyer" at the University of Berlin
^ H. Otto Hirschler, 87, Aided Space Program
^ Neufeld, Michael J. (2013-09-10). The Rocket and the Reich: Peenemunde and the Coming of the Ballistic Missile Era. Smithsonian Institution. p. 138. ISBN 978-1-58834466-3.
^ Ulmann, Bernd (2013-07-22). Analog Computing. Walter de Gruyter. p. 38. ISBN 978-3-48675518-3.
^ Neufeld, Michael J. (1995). The Rocket and the Reich: Peenemünde and the Coming of the Ballistic Missile Era. New York: The Free Press. p. 106.
^ Tomayko, James E. (1985). "Helmut Hoelzer's Fully Electronic Analog Computer". IEEE Annals of the History of Computing. 7 (3): 227–240. doi:10.1109/MAHC.1985.10025. S2CID 15986944.
^ Copeland, B. Jack, ed. (2006). Colossus: The Secrets of Bletchley Park's Codebreaking Computers. Oxford University Press. ISBN 978-0-19-284055-4.
^ Haigh, Thomas (2016). ENIAC in action: making and remaking the modern computer. Mark Priestley, Crispin Rope. Cambridge, Massachusetts, USA; London, UK. pp. 113–114. ISBN 978-0-262-03398-5. OCLC 952615433.{{cite book}}: CS1 maint: location missing publisher (link)
^ Cruz, Frank (2013-11-09). "Programming the ENIAC". Programming the ENIAC. Columbia University. Retrieved 2016-05-16.
^ von Neumann, John (1945). "First Draft of a Report on the EDVAC" (PDF). Retrieved 2014-03-24.
^ "Stored-program concept". Encyclopædia Britannica. Retrieved 2014-03-24.
^ Copeland, Jack (2000). "A Brief History of Computing: ENIAC and EDVAC". Retrieved 2010-01-27. which cites Randell, Brian (1972). Meltzer, B.; Michie, D. (eds.). On Alan Turing and the Origins of Digital Computers. Vol. 7. Edinburgh, UK: Edinburgh University Press. p. 10. ISBN 978-0-902383-26-5. {{cite book}}: |journal= ignored (help)
^ Williams, F. C.; Kilburn, T. (1948-09-25). "Electronic Digital Computers". Nature. 162 (4117): 487. Bibcode:1948Natur.162..487W. doi:10.1038/162487a0. S2CID 4110351. Archived from the original on 2009-04-06. Retrieved 2009-04-10.
^ Susanne Faber, "Konrad Zuses Bemuehungen um die Patentanmeldung der Z3", 2000
^ Zuse, Konrad (2010-04-20). Der Computer – Mein Lebenswerk (in German) (5th ed.). Berlin, Germany: Springer. p. 78. ISBN 978-3-64212095-4. Während des Krieges wäre es freilich ohnehin kaum möglich gewesen, leistungsfähige Geräte mit Speicherprogrammen zu bauen.
^ Anmerkungen zum John von Neumann Rechner by Horst Zuse; F. L. Bauer (original): "Seine erst Jahre später publizierten visionären Ideen (Lebendige Rechenpläne) zielten in die richtige praktische Richtung, wurden von ihm aber nie verwirklicht.
^ Rojas, Raúl. "Reconstruction of Konrad Zuse's Z3 Computer". dcis.inf.fu-berlin.de.
^ "Reconstructing the calculating machine Z3". zuse.zib.de.
^ "Z3-Nachbau-2001" [Z3 replica 2001]. www.horst-zuse.homepage.t-online.de (in German).
^ Zuse, Horst (2013), "Reconstruction of Konrad Zuse's Z3", Making the History of Computing Relevant, IFIP Advances in Information and Communication Technology, vol. 416, Springer Berlin Heidelberg, pp. 287–296, doi:10.1007/978-3-642-41650-7_26, ISBN 978-3-64241649-1
^ Zwernemann-Blech, Irene. "Events during Zuse Year 2010". www.horst-zuse.homepage.t-online.de. Retrieved 2018-11-03.
^ "Z3-Präsentationen" [Z3 – Presentations]. www.horst-zuse.homepage.t-online.de (in German). Retrieved 2018-11-03.

External links

Z3 page at Horst Zuse's website
The Life and Work of Konrad Zuse
How to Make Zuse's Z3 a Universal Computer Raúl Rojas
Raúl Rojas, The Zuse Computers In resurrection, the bulletin of the Computer Conservation Society ISSN 0958-7403 Number 37 Spring 2006
Paul E. Ceruzzi Collection on Konrad Zuse (CBI 219). Charles Babbage Institute, University of Minnesota. Collection contains published reports, articles, product literature, and other materials.

[9] It could solve problems like systems of linear equations and their determinants, quadratic equations and Eigenvalues (for wing flutter).^[7]^[8]

[11] German: Programm für die Berechnung einer komplexen Matrix^[9]

[m8vFl-1] "A Computer Pioneer Rediscovered, 50 Years On". The New York Times. 1994-04-20. Archived from the original on 2016-11-04.

[Morelli-2] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Morelli, Marcello (2001). Dalle calcolatrici ai computer degli anni Cinquanta. FrancoAngeli. p. 177. ISBN 978-8-84642879-0. Retrieved 2014-08-05.

[Zuse_Obituary-3] Weiss, E. (Summer 1996). "Konrad Zuse Obituary". IEEE Annals of the History of Computing. 18 (2): 3–4. doi:10.1109/mahc.1996.489747. ISSN 1058-6180.

[75_years_ago-4] Borchers, Detlef (2016-05-12). "Vor 75 Jahren: Computer Z3 wird vorgeführt" [75 years ago: Computer Z3 is demonstrated]. heise online (in German). Retrieved 2018-05-13.

[Ceruzzi-5] Ceruzzi, Paul E. (1983). "2. Computers in Germany". Reckoners: The Prehistory of The Digital Computer, From Relays to the Stored Program Concept, 1935–1945. Greenwood Press. ISBN 0-313-23382-9. Retrieved 2018-11-03.

[xZ6R4-6] Zuse, Konrad (2013-03-09). The Computer – My Life. Springer Science & Business Media. p. 64. ISBN 978-3-66202931-2.

[Qzdd6-7] Slater, Robert (1989). Portraits in Silicon. MIT Press. pp. 46–47. ISBN 978-0-26269131-4.

[12JdR-8] Schindler, Max J. (1990). Computer-aided software design: build quality software with CASE. Wiley. p. 419. ISBN 9780471506508.

[iwgX0-10] Hellige, Hans Dieter, ed. (2004). Geschichten der Informatik. Visionen, Paradigmen, Leitmotive (in German). Berlin, Germany: Springer. ISBN 978-3-540-00217-8.

[kognitive-strukturen-12] Hohn, Hans-Willy (1998). Kognitive Strukturen und Steuerungsprobleme der Forschung. Kernphysik und Informatik im Vergleich (in German). Schriften des Max-Planck-Instituts für Gesellschaftsforschung Köln. ISBN 978-3-593-36102-4.

[Zptgg-13] "Z3 Computer (1938–1941)". www.computermuseum.li. Archived from the original on 2008-06-17.

[rojas-ieee-14] Rojas, Raúl (1997-09-05). "How to make Zuse's Z3 a universal computer" (PDF). IEEE Annals of the History of Computing. 20 (3) (published July–September 1998): 51–54. doi:10.1109/85.707574.

[7r9WE-15] "Konrad Zuse Biography". RTD Net. From various sides Konrad Zuse was awarded with the title "Inventor of the computer".

[sNTS3-16] "Konrad Zuse". The German Way. The Konrad-Zuse-Zentrum für Informationstechnik Berlin (ZIB), founded in 1986, is a working memorial to the German inventor of the computer.

[4EZM3-17] von Leszczynski, Ulrike (2010-06-27). "Z like Zuse: German inventor of the computer". Monsters & Critics. Archived from the original on 2013-05-22. he [Zuse] built the world's first computer in Berlin

[NllYP-18] Bellis, Mary (2017-07-31). "Konrad Zuse and the Invention of the Modern Computer". Zuse earned the semi-official title of "inventor of the modern computer" for his series of automatic calculators, which he invented to help him with his lengthy engineering calculations.

[autogenerated1-19] Lippe, Wolfram. Kapitel 14 – Die ersten programmierbaren Rechner [The first programmable computers] (PDF) (in German). doi:10.1007/978-3-642-36193-7_6. Archived from the original (PDF) on 2011-07-19. Retrieved 2010-06-21.

[hellige-springer-20] Hellige, Hans Dieter, ed. (2004). Geschichten der Informatik. Visionen, Paradigmen, Leitmotive (in German). Berlin, Germany: Springer. pp. 113, 152. ISBN 978-3-540-00217-8.

[gxiT1-21] Hellige, Hans Dieter, ed. (2004). Geschichten der Informatik. Visionen, Paradigmen, Leitmotive (in German). Berlin, Germany: Springer. p. 102. ISBN 978-3-540-00217-8. Man hat 1939 über uns gelächelt, als wir elektronische Geräte bauen wollten. ... Wir sagten uns damals: Die elektronische Maschine ist wunderbar, aber erst müssen ihre Bauelemente entwickelt werden.

[x1Dzm-22] Hellige, Hans Dieter, ed. (2004). Geschichten der Informatik. Visionen, Paradigmen, Leitmotive (in German). Berlin, Germany: Springer. p. 115. ISBN 978-3-540-00217-8.

[dtSww-23] "New perspectives, computer concepts", June Jamrich Parsons, Dan Oja. Cengage Learning, 2007. ISBN 978-1-4239-0610-0, ISBN 978-1-4239-0610-0. Retrieved 2010-03-14.

[eMcM8-24] Alexander Kauther, Paul Wirtz: Der Einzelkämpfer Dorner. Grin Verlag Gmbh, 2013, ISBN 3-656-04860-6

[lXFGL-25] Helmut Maier: Forschung als Waffe, Wallstein Verlag, 2007, ISBN 3-8353-0109-8, p. 847

[PG7HB-26] "1977-compilation by Zuse of people in contact to his computers from 1935 to 1945" (in German). Archived from the original on 2011-09-28.

[w6xUw-27] Herbert Bruderer, ETH Zurich. "Konrad Zuse und die ETH Zürich" (PDF) (in German). Retrieved 2011-10-26.

[legacy-28] Rojas, Raúl (April–June 1997). "Konrad Zuse's Legacy: The Architecture of the Z1 and Z3" (PDF). IEEE Annals of the History of Computing. 19 (2): 5–15. doi:10.1109/85.586067.

[HZI5q-29] "An einem 12. Mai" (in German). Deutsches Historisches Museum (German Historical Museum).

[6mD7n-30] "Technische Universität Berlin – Rechenhilfe für Ingenieure" (in German). Technical University of Berlin. Archived from the original on 2009-02-13.

[31] "Die Geschichte des DLR-Standorts Berlin-Adlershof" (in German). German Aerospace Center.

[inde_OBIT-32] Campbell-Kelly, Martin (1995-12-21). "OBITUARY: Konrad Zuse". The Independent. Archived from the original on 2022-05-07. Retrieved 2021-05-11.

[CPRYq-33] Zuse, Konrad (1987-10-02). "My First Computer and First Thoughts About Data Processing". history.computer.org. Computer Pioneers – Konrad Zuse. Retrieved 2018-05-14. Search for 1941; ["Computer Design-Past, Present, Future," talk in Lund/Sweden, 1987-10-02, previously unpublished.]

[ZjeJW-34] "Helmut Schreyer" at the University of Berlin

[obituary-35] H. Otto Hirschler, 87, Aided Space Program

[wgm1M-36] Neufeld, Michael J. (2013-09-10). The Rocket and the Reich: Peenemunde and the Coming of the Ballistic Missile Era. Smithsonian Institution. p. 138. ISBN 978-1-58834466-3.

[hoHQm-37] Ulmann, Bernd (2013-07-22). Analog Computing. Walter de Gruyter. p. 38. ISBN 978-3-48675518-3.

[Ja0aX-38] Neufeld, Michael J. (1995). The Rocket and the Reich: Peenemünde and the Coming of the Ballistic Missile Era. New York: The Free Press. p. 106.

[2dYy5-39] Tomayko, James E. (1985). "Helmut Hoelzer's Fully Electronic Analog Computer". IEEE Annals of the History of Computing. 7 (3): 227–240. doi:10.1109/MAHC.1985.10025. S2CID 15986944.

[DQqA3-40] Copeland, B. Jack, ed. (2006). Colossus: The Secrets of Bletchley Park's Codebreaking Computers. Oxford University Press. ISBN 978-0-19-284055-4.

[41] Haigh, Thomas (2016). ENIAC in action: making and remaking the modern computer. Mark Priestley, Crispin Rope. Cambridge, Massachusetts, USA; London, UK. pp. 113–114. ISBN 978-0-262-03398-5. OCLC 952615433.{{cite book}}: CS1 maint: location missing publisher (link)

[42] Cruz, Frank (2013-11-09). "Programming the ENIAC". Programming the ENIAC. Columbia University. Retrieved 2016-05-16.

[pTPDJ-43] von Neumann, John (1945). "First Draft of a Report on the EDVAC" (PDF). Retrieved 2014-03-24.

[KtFgF-44] "Stored-program concept". Encyclopædia Britannica. Retrieved 2014-03-24.

[4Z0Br-45] Copeland, Jack (2000). "A Brief History of Computing: ENIAC and EDVAC". Retrieved 2010-01-27. which cites Randell, Brian (1972). Meltzer, B.; Michie, D. (eds.). On Alan Turing and the Origins of Digital Computers. Vol. 7. Edinburgh, UK: Edinburgh University Press. p. 10. ISBN 978-0-902383-26-5. {{cite book}}: |journal= ignored (help)

[S1Bmn-46] Williams, F. C.; Kilburn, T. (1948-09-25). "Electronic Digital Computers". Nature. 162 (4117): 487. Bibcode:1948Natur.162..487W. doi:10.1038/162487a0. S2CID 4110351. Archived from the original on 2009-04-06. Retrieved 2009-04-10.

[Kh4rD-47] Susanne Faber, "Konrad Zuses Bemuehungen um die Patentanmeldung der Z3", 2000

[qfA84-48] Zuse, Konrad (2010-04-20). Der Computer – Mein Lebenswerk (in German) (5th ed.). Berlin, Germany: Springer. p. 78. ISBN 978-3-64212095-4. Während des Krieges wäre es freilich ohnehin kaum möglich gewesen, leistungsfähige Geräte mit Speicherprogrammen zu bauen.

[WiPHo-49] Anmerkungen zum John von Neumann Rechner by Horst Zuse; F. L. Bauer (original): "Seine erst Jahre später publizierten visionären Ideen (Lebendige Rechenpläne) zielten in die richtige praktische Richtung, wurden von ihm aber nie verwirklicht.

[LMSxR-50] Rojas, Raúl. "Reconstruction of Konrad Zuse's Z3 Computer". dcis.inf.fu-berlin.de.

[snbXk-51] "Reconstructing the calculating machine Z3". zuse.zib.de.

[qEXYi-52] "Z3-Nachbau-2001" [Z3 replica 2001]. www.horst-zuse.homepage.t-online.de (in German).

[TnNVK-53] Zuse, Horst (2013), "Reconstruction of Konrad Zuse's Z3", Making the History of Computing Relevant, IFIP Advances in Information and Communication Technology, vol. 416, Springer Berlin Heidelberg, pp. 287–296, doi:10.1007/978-3-642-41650-7_26, ISBN 978-3-64241649-1

[Oe8xY-54] Zwernemann-Blech, Irene. "Events during Zuse Year 2010". www.horst-zuse.homepage.t-online.de. Retrieved 2018-11-03.

[SLUQC-55] "Z3-Präsentationen" [Z3 – Presentations]. www.horst-zuse.homepage.t-online.de (in German). Retrieved 2018-11-03.

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@@ Line 1: / Line 1: @@
 {{Short description|First working programmable, fully automatic digital computer}}
 {{Other uses|Z3 (disambiguation){{!}}Z3}}
+{{Use dmy dates|date=July 2022|cs1-dates=y}}
-<!-- Is the following img to be uploaded and included in the article? --Wernher -->
-<!-- http://irb.cs.tu-berlin.de/~zuse/Konrad_Zuse/img/Rechner_Z3_1.jpg          -->
 [[File:Z3 Deutsches Museum.JPG|thumb|upright=1.35|Zuse Z3 replica on display at [[Deutsches Museum]] in [[Munich]]]]
-The '''Z3''' was a German [[electromechanical computer]] designed by [[Konrad Zuse]] in 1935, and completed in 1941. It was the world's first working [[Computer programming|programmable]], fully automatic [[digital computer]].<ref name="m8vFl">{{cite news|url=https://www.nytimes.com/1994/04/20/news/20iht-zuse.html|title=A Computer Pioneer Rediscovered, 50 Years On|date=April 20, 1994|newspaper=The New York Times|url-status=dead|archive-url=https://web.archive.org/web/20161104051054/http://www.nytimes.com/1994/04/20/news/20iht-zuse.html|archive-date=November 4, 2016|df=mdy-all}}</ref> The Z3 was built with 2,600 [[relay]]s, implementing a 22-[[bit]] [[Word (data type)|word]] length that operated at a [[clock frequency]] of about 5–10&nbsp;[[Hertz|Hz]].<ref name="Morelli" /> Program code was stored on punched [[celluloid|film]]. Initial values were entered manually.<ref name="Zuse Obituary">{{Cite journal|last=Weiss|first=E.|date=Summer 1996|title=Konrad Zuse Obituary|journal=IEEE Annals of the History of Computing|language=en-US|volume=18|issue=2|pages=3–4|doi=10.1109/mahc.1996.489747|issn=1058-6180}}</ref><ref name="75 years ago">{{Cite web|url=https://www.heise.de/newsticker/meldung/Vor-75-Jahren-Computer-Z3-wird-vorgefuehrt-3205261.html|title=Vor 75 Jahren: Computer Z3 wird vorgeführt|last=Borchers|first=Detlef|date=2016-05-12|website=heise online|language=de-DE|trans-title=75 years ago: Computer Z3 is demonstrated|access-date=2018-05-13}} ([https://translate.google.com/translate?sl=auto&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=https%3A%2F%2Fwww.heise.de%2Fnewsticker%2Fmeldung%2FVor-75-Jahren-Computer-Z3-wird-vorgefuehrt-3205261.html&edit-text= Google translation])</ref><ref name="Ceruzzi">{{cite book|last=Ceruzzi|first=Paul|title=Reckoners: The Prehistory of The Digital Computer, From Relays to the Stored Program Concept, 1935–1945|publisher=Greenwood Press|year=1983|chapter=2. Computers in Germany|isbn=0-313-23382-9|chapter-url=http://ed-thelen.org/comp-hist/Reckoners-ch-2.html|access-date=2018-11-03}}</ref>{{rp|32–37}}
+The '''Z3''' was a German [[electromechanical computer]] designed by [[Konrad Zuse]] in 1935, and completed in 1941. It was the world's first working [[Computer programming|programmable]], fully automatic [[digital computer]].<ref name="m8vFl">{{cite news |url=https://www.nytimes.com/1994/04/20/news/20iht-zuse.html |title=A Computer Pioneer Rediscovered, 50 Years On |date=1994-04-20 |newspaper=[[The New York Times]] |url-status=dead |archive-url=https://web.archive.org/web/20161104051054/http://www.nytimes.com/1994/04/20/news/20iht-zuse.html |archive-date=2016-11-04}}</ref> The Z3 was built with 2,600 [[relay]]s, implementing a 22-[[bit]] [[Word (data type)|word]] length that operated at a [[clock frequency]] of about 5–10&nbsp;[[Hertz|Hz]].<ref name="Morelli"/> Program code was stored on punched [[celluloid|film]]. Initial values were entered manually.<ref name="Zuse Obituary">{{Cite journal |author-last=Weiss |author-first=E. |date=Summer 1996 |title=Konrad Zuse Obituary |journal=[[IEEE Annals of the History of Computing]] |language=en-US |volume=18 |issue=2 |pages=3–4 |doi=10.1109/mahc.1996.489747 |issn=1058-6180}}</ref><ref name="75 years ago">{{Cite web |url=https://www.heise.de/newsticker/meldung/Vor-75-Jahren-Computer-Z3-wird-vorgefuehrt-3205261.html |title=Vor 75 Jahren: Computer Z3 wird vorgeführt |author-last=Borchers |author-first=Detlef |date=2016-05-12 |website=heise online |language=de-DE |trans-title=75 years ago: Computer Z3 is demonstrated |access-date=2018-05-13}}</ref><ref name="Ceruzzi">{{cite book |author-last=Ceruzzi |author-first=Paul E. |title=Reckoners: The Prehistory of The Digital Computer, From Relays to the Stored Program Concept, 1935–1945 |publisher=Greenwood Press |date=1983 |chapter=2. Computers in Germany |isbn=0-313-23382-9 |chapter-url=http://ed-thelen.org/comp-hist/Reckoners-ch-2.html |access-date=2018-11-03}}</ref>{{rp|32–37}}
-The Z3 was completed in [[Berlin]] in 1941. It was not considered vital, so it was never put into everyday operation.<ref name="Zuse Obituary" /><ref name="75 years ago" /><ref name="xZ6R4">{{Cite book|url=https://books.google.com/books?id=edWoCAAAQBAJ&pg=PA64|title=The Computer – My Life|last=Zuse|first=Konrad|date=2013-03-09|publisher=Springer Science & Business Media|isbn=9783662029312|page=64|language=en}}</ref><ref name="Ceruzzi" />{{rp|30, 38–39}}{{efn|1=It could solve problems like systems of linear equations and their determinants, quadratic equations and Eigenvalues (for [[wing flutter]]).<ref name="Qzdd6">{{Cite book|url=https://books.google.com/books?id=aWTtMyYmKhUC&pg=PA46|title=Portraits in Silicon|last=Slater|first=Robert|date=1989|publisher=MIT Press|isbn=9780262691314|pages=46–47|language=en}}</ref><ref name="12JdR">{{Cite book|url=https://books.google.com/books?id=uxWzAAAAIAAJ&q=determinants|title=Computer-aided software design: build quality software with CASE|last=Schindler|first=Max J.|date=1990|publisher=Wiley|isbn=9780471506508|page=419|language=en}}</ref>}} Based on the work of the German [[aerodynamics]] engineer [[Hans Georg Küssner]] (known for the [[Küssner effect]]), a "Program to Compute a Complex Matrix"{{efn|1={{lang-de|Programm für die Berechnung einer komplexen Matrix}}<ref name="iwgX0">{{cite book|editor=Hans Dieter Hellige|title=Geschichten der Informatik. Visionen, Paradigmen, Leitmotive|language=de|publisher=Springer|location=Berlin|year=2004|isbn=978-3-540-00217-8}}</ref>}} was written and used to solve [[wing flutter]] problems. Zuse asked the German government for funding to replace the relays with fully electronic switches, but funding was denied during [[World War II]] since such development was deemed "not war-important".<ref name="kognitive-strukturen">{{cite book |author=Hans-Willy Hohn |title= Kognitive Strukturen und Steuerungsprobleme der Forschung. Kernphysik und Informatik im Vergleich |year=1998 |publisher=Schriften des Max-Planck-Instituts für Gesellschaftsforschung Köln |language=de |isbn= 978-3-593-36102-4}}</ref>{{rp|148}}
+The Z3 was completed in [[Berlin]] in 1941. It was not considered vital, so it was never put into everyday operation.<ref name="Zuse Obituary"/><ref name="75 years ago"/><ref name="xZ6R4">{{Cite book |url=https://books.google.com/books?id=edWoCAAAQBAJ&pg=PA64|title=The Computer – My Life |author-last=Zuse |author-first=Konrad |date=2013-03-09 |publisher=Springer Science & Business Media |isbn=978-3-66202931-2 |page=64 |language=en}}</ref><ref name="Ceruzzi"/>{{rp|30, 38–39}}{{efn|1=It could solve problems like systems of linear equations and their determinants, quadratic equations and Eigenvalues (for [[wing flutter]]).<ref name="Qzdd6">{{Cite book |url=https://books.google.com/books?id=aWTtMyYmKhUC&pg=PA46 |title=Portraits in Silicon |author-last=Slater |author-first=Robert |date=1989 |publisher=MIT Press |isbn=978-0-26269131-4 |pages=46–47 |language=en}}</ref><ref name="12JdR">{{Cite book |url=https://books.google.com/books?id=uxWzAAAAIAAJ&q=determinants |title=Computer-aided software design: build quality software with CASE |author-last=Schindler |author-first=Max J. |date=1990 |publisher=Wiley |isbn=9780471506508 |page=419 |language=en}}</ref>}} Based on the work of the German [[aerodynamics]] engineer [[Hans Georg Küssner]] (known for the [[Küssner effect]]), a "Program to Compute a Complex Matrix"{{efn|1={{lang-de|Programm für die Berechnung einer komplexen Matrix}}<ref name="iwgX0">{{cite book |editor-first=Hans Dieter |editor-last=Hellige |title=Geschichten der Informatik. Visionen, Paradigmen, Leitmotive |language=de |publisher=Springer |location=Berlin, Germany |date=2004 |isbn=978-3-540-00217-8}}</ref>}} was written and used to solve [[wing flutter]] problems. Zuse asked the German government for funding to replace the relays with fully electronic switches, but funding was denied during [[World War II]] since such development was deemed "not war-important".<ref name="kognitive-strukturen">{{cite book |author-first=Hans-Willy |author-last=Hohn |title=Kognitive Strukturen und Steuerungsprobleme der Forschung. Kernphysik und Informatik im Vergleich |date=1998 |publisher=Schriften des Max-Planck-Instituts für Gesellschaftsforschung Köln |language=de |isbn=978-3-593-36102-4}}</ref>{{rp|148}}
-The original Z3 was destroyed on 21 December 1943 during an [[Bombing of Berlin during World War II|Allied bombardment of Berlin]]. That Z3 was originally called V3 (''Versuchsmodell 3'' or Experimental Model 3) but was renamed so that it would not be confused with Germany's [[V-weapons]].<ref name="Zptgg">{{cite web|url=http://www.computermuseum.li/Testpage/Z3-Computer-1939.htm|title=Z3 Computer (1938–1941)|archive-url=https://web.archive.org/web/20080617234903/http://www.computermuseum.li/Testpage/Z3-Computer-1939.htm|archive-date=2008-06-17|website=www.computermuseum.li}}</ref> A fully functioning replica was built in 1961 by Zuse's company, Zuse [[Kommanditgesellschaft|KG]], which is now on permanent display at [[Deutsches Museum]] in [[Munich]].<ref name="Ceruzzi" />{{rp|30}}
+The original Z3 was destroyed on 21 December 1943 during an [[Bombing of Berlin during World War II|Allied bombardment of Berlin]]. That Z3 was originally called V3 (''Versuchsmodell 3'' or Experimental Model 3) but was renamed so that it would not be confused with Germany's [[V-weapons]].<ref name="Zptgg">{{cite web |url=http://www.computermuseum.li/Testpage/Z3-Computer-1939.htm |title=Z3 Computer (1938–1941) |archive-url=https://web.archive.org/web/20080617234903/http://www.computermuseum.li/Testpage/Z3-Computer-1939.htm |archive-date=2008-06-17 |website=www.computermuseum.li}}</ref> A fully functioning replica was built in 1961 by Zuse's company, Zuse [[Kommanditgesellschaft|KG]], which is now on permanent display at [[Deutsches Museum]] in [[Munich]].<ref name="Ceruzzi" />{{rp|30}}
-The Z3 was demonstrated in 1998 to be, in principle, [[Turing-complete]].<ref name="rojas-ieee">{{cite journal|last=Rojas|first=R.|author-link=Raúl Rojas|date=September 5, 1997|publication-date=Jul–Sep 1998|title=How to make Zuse's Z3 a universal computer|url=http://www.inf.fu-berlin.de/users/rojas/1997/Universal_Computer.pdf|journal=IEEE Annals of the History of Computing|volume=20|issue=3|pages=51–54|doi=10.1109/85.707574}}</ref> However, because it lacked [[conditional branching]], the Z3 only meets this definition by speculatively computing all possible outcomes of a calculation.
+The Z3 was demonstrated in 1998 to be, in principle, [[Turing-complete]].<ref name="rojas-ieee">{{cite journal |author-last=Rojas |author-first=Raúl |author-link=Raúl Rojas |date=1997-09-05 |publication-date=July–September 1998 |title=How to make Zuse's Z3 a universal computer |url=http://www.inf.fu-berlin.de/users/rojas/1997/Universal_Computer.pdf |journal=IEEE Annals of the History of Computing |volume=20 |issue=3 |pages=51–54 |doi=10.1109/85.707574}}</ref> However, because it lacked [[conditional branching]], the Z3 only meets this definition by speculatively computing all possible outcomes of a calculation.
-Thanks to this machine and its predecessors, [[Konrad Zuse]] has often been suggested as the inventor of the computer.<ref name="7r9WE">{{cite web|url=http://www.rtd-net.de/Zuse.html|title=Konrad Zuse Biography|website=RTD Net|quote=From various sides Konrad Zuse was awarded with the title "Inventor of the computer".}}</ref><ref name="sNTS3">{{cite web|url=https://www.german-way.com/notable-people/featured-bios/konrad-zuse/|title=Konrad Zuse|website=The German Way|quote=The Konrad-Zuse-Zentrum für Informationstechnik Berlin (ZIB), founded in 1986, is a working memorial to the German inventor of the computer.}}</ref><ref name="4EZM3">{{cite web|url=http://www.monstersandcritics.com/tech/features/article_1566782.php/Z-like-Zuse-German-inventor-of-the-computer|title=Z like Zuse: German inventor of the computer|author=Ulrike von Leszczynski|date=2010-06-27|website=[[Monsters & Critics]]|archive-url=https://web.archive.org/web/20130522022610/http://www.monstersandcritics.com/tech/features/article_1566782.php/Z-like-Zuse-German-inventor-of-the-computer|archive-date=2013-05-22|quote=he(Zuse) built the world's first computer in Berlin}}</ref><ref name="NllYP">{{cite web|url=https://www.thoughtco.com/konrad-zuse-modern-computer-4078237|title=Konrad Zuse and the Invention of the Modern Computer|author=Mary Bellis|date=2017-07-31|quote=Zuse earned the semi-official title of "inventor of the modern computer" for his series of automatic calculators, which he invented to help him with his lengthy engineering calculations.}}</ref>
+Thanks to this machine and its predecessors, [[Konrad Zuse]] has often been suggested as the inventor of the computer.<ref name="7r9WE">{{cite web |url=http://www.rtd-net.de/Zuse.html |title=Konrad Zuse Biography |website=RTD Net |quote=From various sides Konrad Zuse was awarded with the title "Inventor of the computer".}}</ref><ref name="sNTS3">{{cite web |url=https://www.german-way.com/notable-people/featured-bios/konrad-zuse/ |title=Konrad Zuse |website=The German Way |quote=The Konrad-Zuse-Zentrum für Informationstechnik Berlin (ZIB), founded in 1986, is a working memorial to the German inventor of the computer.}}</ref><ref name="4EZM3">{{cite web |url=http://www.monstersandcritics.com/tech/features/article_1566782.php/Z-like-Zuse-German-inventor-of-the-computer |title=Z like Zuse: German inventor of the computer |author-first=Ulrike |author-last=von Leszczynski |date=2010-06-27 |website=[[Monsters & Critics]] |archive-url=https://web.archive.org/web/20130522022610/http://www.monstersandcritics.com/tech/features/article_1566782.php/Z-like-Zuse-German-inventor-of-the-computer |archive-date=2013-05-22 |quote=he [Zuse] built the world's first computer in Berlin}}</ref><ref name="NllYP">{{cite web |url=https://www.thoughtco.com/konrad-zuse-modern-computer-4078237 |title=Konrad Zuse and the Invention of the Modern Computer |author-first=Mary |author-last=Bellis |date=2017-07-31 |quote=Zuse earned the semi-official title of "inventor of the modern computer" for his series of automatic calculators, which he invented to help him with his lengthy engineering calculations.}}</ref>
 == Design and development ==
-Zuse designed the [[Z1 (computer)|Z1]] in 1935 to 1936 and built it from 1936 to 1938. The Z1 was wholly mechanical and only worked for a few minutes at a time at most. [[Helmut Schreyer]] advised Zuse to use a different technology. As a doctoral student at the [[Berlin Institute of Technology]] in 1937 he worked on the implementation of Boolean operations and (in today's terminology) [[flip-flop (electronics)|flip-flops]] on the basis of [[vacuum tube]]s. In 1938 Schreyer demonstrated a circuit on this basis to a small audience, and explained his vision of an electronic computing machine – but since the largest operational electronic devices contained far fewer tubes this was considered practically infeasible.<ref name="autogenerated1">{{cite book|last=Lippe|first=Wolfram|title=Kapitel 14 – Die ersten programmierbaren Rechner|trans-title=The first programmable computers|doi= 10.1007/978-3-642-36193-7_6|url=http://cs.uni-muenster.de/Professoren/Lippe/lehre/skripte/geschichte/pdf/Kap14.pdf|language=de|access-date=2010-06-21|url-status=dead|archive-url=https://web.archive.org/web/20110719110029/http://cs.uni-muenster.de/Professoren/Lippe/lehre/skripte/geschichte/pdf/Kap14.pdf|archive-date=2011-07-19}}</ref> In that year when presenting the plan for a computer with 2,000 electron tubes, Zuse and Schreyer, who was an assistant at {{ill|Wilhelm Stäblein|lt=Wilhelm Stäblein's|de}} Telecommunication Institute at the Technical University of Berlin, were discouraged by members of the institute who knew about the problems with electron tube technology.<ref name="hellige-springer">{{cite book|editor=Hans Dieter Hellige|title=Geschichten der Informatik. Visionen, Paradigmen, Leitmotive|language=de |location=Berlin|publisher=Springer|year=2004|isbn=978-3-540-00217-8|pages=113, 152}}</ref> Zuse later recalled: "They smiled at us in 1939, when we wanted to build electronic machines ... We said: The electronic machine is great, but first the [[Electronic component|components]] have to be developed."<ref name="gxiT1">{{cite book|editor=Hans Dieter Hellige|year=2004|title=Geschichten der Informatik. Visionen, Paradigmen, Leitmotive|language=de|location=Berlin|publisher=Springer|page=102|isbn=978-3-540-00217-8|quote=Man hat 1939 über uns gelächelt, als wir elektronische Geräte bauen wollten. ... Wir sagten uns damals: Die elektronische Maschine ist wunderbar, aber erst müssen ihre Bauelemente entwickelt werden.}}</ref> In 1940 Zuse and Schreyer managed to arrange a meeting at the [[Oberkommando der Wehrmacht]] (OKW) to discuss a potential project for developing an electronic computer, but when they estimated a duration of two or three years, the proposal was rejected.<ref name="x1Dzm">{{cite book|editor=Hans Dieter Hellige|year=2004|title=Geschichten der Informatik. Visionen, Paradigmen, Leitmotive|language=de|location=Berlin|publisher=Springer|page=115|isbn=978-3-540-00217-8}}</ref>
+Zuse designed the [[Z1 (computer)|Z1]] in 1935 to 1936 and built it from 1936 to 1938. The Z1 was wholly mechanical and only worked for a few minutes at a time at most. [[Helmut Schreyer]] advised Zuse to use a different technology. As a doctoral student at the [[Berlin Institute of Technology]] in 1937 he worked on the implementation of Boolean operations and (in today's terminology) [[flip-flop (electronics)|flip-flops]] on the basis of [[vacuum tube]]s. In 1938 Schreyer demonstrated a circuit on this basis to a small audience, and explained his vision of an electronic computing machine – but since the largest operational electronic devices contained far fewer tubes this was considered practically infeasible.<ref name="autogenerated1">{{cite book |author-last=Lippe |author-first=Wolfram |title=Kapitel 14 – Die ersten programmierbaren Rechner |trans-title=The first programmable computers |doi=10.1007/978-3-642-36193-7_6 |url=http://cs.uni-muenster.de/Professoren/Lippe/lehre/skripte/geschichte/pdf/Kap14.pdf |language=de |access-date=2010-06-21 |url-status=dead |archive-url=https://web.archive.org/web/20110719110029/http://cs.uni-muenster.de/Professoren/Lippe/lehre/skripte/geschichte/pdf/Kap14.pdf |archive-date=2011-07-19}}</ref> In that year when presenting the plan for a computer with 2,000 electron tubes, Zuse and Schreyer, who was an assistant at {{ill|Wilhelm Stäblein|lt=Wilhelm Stäblein's|de}} Telecommunication Institute at the Technical University of Berlin, were discouraged by members of the institute who knew about the problems with electron tube technology.<ref name="hellige-springer">{{cite book |editor-first=Hans Dieter |editor-last=Hellige |title=Geschichten der Informatik. Visionen, Paradigmen, Leitmotive |language=de |location=Berlin, Germany |publisher=Springer |date=2004 |isbn=978-3-540-00217-8 |pages=113, 152}}</ref> Zuse later recalled: "They smiled at us in 1939, when we wanted to build electronic machines ... We said: The electronic machine is great, but first the [[Electronic component|components]] have to be developed."<ref name="gxiT1">{{cite book |editor-first=Hans Dieter |editor-last=Hellige |date=2004 |title=Geschichten der Informatik. Visionen, Paradigmen, Leitmotive |language=de |location=Berlin, Germany |publisher=Springer |page=102 |isbn=978-3-540-00217-8 |quote=Man hat 1939 über uns gelächelt, als wir elektronische Geräte bauen wollten. ... Wir sagten uns damals: Die elektronische Maschine ist wunderbar, aber erst müssen ihre Bauelemente entwickelt werden.}}</ref> In 1940 Zuse and Schreyer managed to arrange a meeting at the [[Oberkommando der Wehrmacht]] (OKW) to discuss a potential project for developing an electronic computer, but when they estimated a duration of two or three years, the proposal was rejected.<ref name="x1Dzm">{{cite book |editor-first=Hans Dieter |editor-last=Hellige |date=2004 |title=Geschichten der Informatik. Visionen, Paradigmen, Leitmotive |language=de |location=Berlin, Germany |publisher=Springer |page=115 |isbn=978-3-540-00217-8}}</ref>
-Zuse decided to implement the next design based on relays. The realization of the [[Z2 (computer)|Z2]] was helped financially by [[Kurt Pannke]], who manufactured small calculating machines. The Z2 was completed and presented to an audience of the {{lang|de|Deutsche Versuchsanstalt für Luftfahrt}} ("German Laboratory for Aviation") in 1940 in Berlin-Adlershof. Zuse was lucky – this presentation was one of the few instances where the Z2 actually worked and could convince the DVL to partly finance the next design.<ref name="autogenerated1" />
+Zuse decided to implement the next design based on relays. The realization of the [[Z2 (computer)|Z2]] was helped financially by [[Kurt Pannke]], who manufactured small calculating machines. The Z2 was completed and presented to an audience of the {{lang|de|Deutsche Versuchsanstalt für Luftfahrt}} ("German Laboratory for Aviation") in 1940 in Berlin-Adlershof. Zuse was lucky – this presentation was one of the few instances where the Z2 actually worked and could convince the DVL to partly finance the next design.<ref name="autogenerated1"/>
-Improving on the basic Z2 machine, he built the Z3 in 1941, which was a highly secret project of the German government.<ref name="dtSww">[https://books.google.com/books?id=VVVVkm9G5jgC&pg=PA489&dq=konrad+zuse,+nazi&lr=&cd=12#v=onepage&q=konrad%20zuse%2C%20nazi&f=false "New perspectives, computer concepts"], June Jamrich Parsons, Dan Oja. Cengage Learning, 2007. {{ISBN|978-1-4239-0610-0}}, {{ISBN|978-1-4239-0610-0}}. Retrieved March 14, 2010.</ref> [[Joseph Jennissen]] (1905–1977),<ref name="eMcM8">Alexander Kauther, Paul Wirtz: ''Der Einzelkämpfer Dorner''. Grin Verlag Gmbh, 2013, {{ISBN|3-656-04860-6}}</ref> member of the "Research-Leadership" (''Forschungsführung'') in the [[Air Ministry (Germany)|Reich Air Ministry]]<ref name="lXFGL">Helmut Maier: ''Forschung als Waffe'', Wallstein Verlag, 2007, {{ISBN|3-8353-0109-8}}, p. 847</ref> acted as a government supervisor for orders of the ministry to Zuse's company ''ZUSE Apparatebau''.<ref name="PG7HB">{{cite web|url=http://www.zib.de/zuse/Inhalt/Texte/Chrono/60er/Html/0315/0315.html|title=1977-compilation by Zuse of people in contact to his computers from 1935 to 1945|language=de|archive-url=https://web.archive.org/web/20110928123346/http://www.zib.de/zuse/Inhalt/Texte/Chrono/60er/Html/0315/0315.html|archive-date=2011-09-28}}</ref> A further intermediary between Zuse and the Reich Air Ministry was the aerodynamicist [[Herbert A. Wagner]].<ref name="w6xUw">{{cite web |url=http://e-collection.library.ethz.ch/eserv/eth:2428/eth-2428-01.pdf |title=Konrad Zuse und die ETH Zürich |language=de |author=Herbert Bruderer, [[ETH Zurich]] |access-date=2011-10-26}}</ref>
+Improving on the basic Z2 machine, he built the Z3 in 1941, which was a highly secret project of the German government.<ref name="dtSww">[https://books.google.com/books?id=VVVVkm9G5jgC&pg=PA489&dq=konrad+zuse,+nazi&lr=&cd=12#v=onepage&q=konrad%20zuse%2C%20nazi&f=false "New perspectives, computer concepts"], June Jamrich Parsons, Dan Oja. Cengage Learning, 2007. {{ISBN|978-1-4239-0610-0}}, {{ISBN|978-1-4239-0610-0}}. Retrieved 2010-03-14.</ref> [[Joseph Jennissen]] (1905–1977),<ref name="eMcM8">Alexander Kauther, Paul Wirtz: ''Der Einzelkämpfer Dorner''. Grin Verlag Gmbh, 2013, {{ISBN|3-656-04860-6}}</ref> member of the "Research-Leadership" (''Forschungsführung'') in the [[Air Ministry (Germany)|Reich Air Ministry]]<ref name="lXFGL">Helmut Maier: ''Forschung als Waffe'', Wallstein Verlag, 2007, {{ISBN|3-8353-0109-8}}, p. 847</ref> acted as a government supervisor for orders of the ministry to Zuse's company ''ZUSE Apparatebau''.<ref name="PG7HB">{{cite web |url=http://www.zib.de/zuse/Inhalt/Texte/Chrono/60er/Html/0315/0315.html |title=1977-compilation by Zuse of people in contact to his computers from 1935 to 1945 |language=de |archive-url=https://web.archive.org/web/20110928123346/http://www.zib.de/zuse/Inhalt/Texte/Chrono/60er/Html/0315/0315.html |archive-date=2011-09-28}}</ref> A further intermediary between Zuse and the Reich Air Ministry was the aerodynamicist [[Herbert A. Wagner]].<ref name="w6xUw">{{cite web |url=http://e-collection.library.ethz.ch/eserv/eth:2428/eth-2428-01.pdf |title=Konrad Zuse und die ETH Zürich |language=de |author=Herbert Bruderer, [[ETH Zurich]] |access-date=2011-10-26}}</ref>
-The Z3 was completed in 1941 and was faster and far more reliable than the Z1 and Z2. The Z3 [[floating-point arithmetic]] was improved over that of the Z1 in that it implemented exception handling "using just a few relays", the exceptional values (plus infinity, minus infinity and undefined) could be generated and passed through operations. The Z3 stored its program on an external punched tape, thus no rewiring was necessary to change programs. However, it did not have conditional branching found in later universal computers.<ref name="legacy">{{cite journal |url=http://ed-thelen.org/comp-hist/Zuse_Z1_and_Z3.pdf |title=Konrad Zuse's Legacy: The Architecture of the Z1 and Z3 |journal=[[IEEE Annals of the History of Computing]] |volume=19 |number=2 |date=April–June 1997 |pages=5–15 |doi=10.1109/85.586067|last1=Rojas |first1=R}}</ref>{{rp|7}}
+The Z3 was completed in 1941 and was faster and far more reliable than the Z1 and Z2. The Z3 [[floating-point arithmetic]] was improved over that of the Z1 in that it implemented exception handling "using just a few relays", the exceptional values (plus infinity, minus infinity and undefined) could be generated and passed through operations. The Z3 stored its program on an external punched tape, thus no rewiring was necessary to change programs. However, it did not have conditional branching found in later universal computers.<ref name="legacy">{{cite journal |url=http://ed-thelen.org/comp-hist/Zuse_Z1_and_Z3.pdf |title=Konrad Zuse's Legacy: The Architecture of the Z1 and Z3 |journal=[[IEEE Annals of the History of Computing]] |volume=19 |number=2 |date=April–June 1997 |pages=5–15 |doi=10.1109/85.586067 |author-last=Rojas |author-first=Raúl}}</ref>{{rp|7}}
-On 12 May 1941 the Z3 was presented to an audience of scientists including the professors Alfred Teichmann and Curt Schmieden<ref name="HZI5q">{{cite web |url=http://www.dhm.de/gaeste/luise/tagesfakten/tf05/0512.htm |title=An einem 12. Mai |language=de |publisher=[[Deutsches Historisches Museum]] (German Historical Museum)}} ([https://translate.google.com/translate?sl=auto&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=https%3A%2F%2Fwww.dhm.de%2Farchiv%2Fgaeste%2Fluise%2Ftagesfakten%2Ftf05%2F0512.htm&edit-text= Google translation])</ref> of the {{lang|de|Deutsche Versuchsanstalt für Luftfahrt}} ("German Laboratory for Aviation") in [[Berlin]],<ref name="6mD7n">{{cite web |url=http://www2.tu-berlin.de/alumni/parTU/00dez/zuse.htm |title=Technische Universität Berlin – Rechenhilfe für Ingenieure |language=de |publisher=[[Technical University of Berlin]] |url-status=dead |archive-url=https://web.archive.org/web/20090213222711/http://www2.tu-berlin.de/alumni/parTU/00dez/zuse.htm |archive-date=2009-02-13}} ([https://translate.google.com/translate?sl=auto&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=https%3A%2F%2Fweb.archive.org%2Fweb%2F20090213222711%2Fhttp%3A%2F%2Fwww2.tu-berlin.de%2Falumni%2FparTU%2F00dez%2Fzuse.htm&edit-text= Google translation])</ref> today known as the [[German Aerospace Center]] in [[Cologne]].<ref>{{cite web |title=Die Geschichte des DLR-Standorts Berlin-Adlershof |language=de |url=https://www.dlr.de/content/de/artikel/standorte/berlin/geschichte-berlin.html |publisher=[[German Aerospace Center]]}}</ref>
+On 12 May 1941 the Z3 was presented to an audience of scientists including the professors Alfred Teichmann and Curt Schmieden<ref name="HZI5q">{{cite web |url=http://www.dhm.de/gaeste/luise/tagesfakten/tf05/0512.htm |title=An einem 12. Mai |language=de |publisher=[[Deutsches Historisches Museum]] (German Historical Museum)}}</ref> of the {{lang|de|Deutsche Versuchsanstalt für Luftfahrt}} ("German Laboratory for Aviation") in [[Berlin]],<ref name="6mD7n">{{cite web |url=http://www2.tu-berlin.de/alumni/parTU/00dez/zuse.htm |title=Technische Universität Berlin – Rechenhilfe für Ingenieure |language=de |publisher=[[Technical University of Berlin]] |url-status=dead |archive-url=https://web.archive.org/web/20090213222711/http://www2.tu-berlin.de/alumni/parTU/00dez/zuse.htm |archive-date=2009-02-13}}</ref> today known as the [[German Aerospace Center]] in [[Cologne]].<ref>{{cite web |title=Die Geschichte des DLR-Standorts Berlin-Adlershof |language=de |url=https://www.dlr.de/content/de/artikel/standorte/berlin/geschichte-berlin.html |publisher=[[German Aerospace Center]]}}</ref>
-Zuse moved on to the [[Z4 (computer)|Z4]] design, which he completed in a bunker in the [[Harz]] mountains, alongside [[Wernher von Braun]]'s ballistic missile development. When World War II ended, Zuse retreated to [[Hinterstein]] in the Alps with the Z4, where he remained for several years.<ref name="inde_OBIT">{{Cite web |title=OBITUARY : Konrad Zuse |last=Campbell-Kelly |first=Martin |work=The Independent |date=21 December 1995 |access-date=11 May 2021 |url= https://www.independent.co.uk/news/people/obituary-konrad-zuse-1526795.html |archive-url=https://ghostarchive.org/archive/20220507/https://www.independent.co.uk/news/people/obituary-konrad-zuse-1526795.html |archive-date=2022-05-07 |url-access=subscription |url-status=live}}{{cbignore}}</ref>
+Zuse moved on to the [[Z4 (computer)|Z4]] design, which he completed in a bunker in the [[Harz]] mountains, alongside [[Wernher von Braun]]'s ballistic missile development. When World War II ended, Zuse retreated to [[Hinterstein]] in the Alps with the Z4, where he remained for several years.<ref name="inde_OBIT">{{Cite web |title=OBITUARY: Konrad Zuse |author-last=Campbell-Kelly |author-first=Martin |work=The Independent |date=1995-12-21 |access-date=2021-05-11 |url=https://www.independent.co.uk/news/people/obituary-konrad-zuse-1526795.html |archive-url=https://ghostarchive.org/archive/20220507/https://www.independent.co.uk/news/people/obituary-konrad-zuse-1526795.html |archive-date=2022-05-07 |url-access=subscription |url-status=live}}{{cbignore}}</ref>
 == Instruction set ==
-The Z3 operated as a [[stack machine]] with a stack of two registers, R1 and R2.  The first load operation in a program would load the contents of a memory location into R1; the next load operation would load the contents of a memory location into R2.  Arithmetic instructions would operate on the contents of R1 and R2, leaving the result in R1, and clearing R2; the next load operation would load into R2.  A store operation would store the contents of R1 into a memory location, and clear R1; the next load operation would load the contents of a memory location into R1.<ref name="legacy" />{{rp|8}}
+The Z3 operated as a [[stack machine]] with a stack of two registers, R1 and R2.  The first load operation in a program would load the contents of a memory location into R1; the next load operation would load the contents of a memory location into R2.  Arithmetic instructions would operate on the contents of R1 and R2, leaving the result in R1, and clearing R2; the next load operation would load into R2.  A store operation would store the contents of R1 into a memory location, and clear R1; the next load operation would load the contents of a memory location into R1.<ref name="legacy"/>{{rp|8}}
-A read keyboard operation would read a number from the keyboard into R1 and clear R2.  A display instruction would display the contents of R1 and clear R2; the next load instruction would load into R2.<ref name="legacy" />{{rp|8}}
+A read keyboard operation would read a number from the keyboard into R1 and clear R2.  A display instruction would display the contents of R1 and clear R2; the next load instruction would load into R2.<ref name="legacy"/>{{rp|8}}
 == Z3 as a universal Turing machine ==
-It was possible to construct loops on the Z3, but there was no [[conditional branch]] instruction. Nevertheless, the Z3 was [[Turing-complete]] – how to implement a universal [[Turing machine]] on the Z3 was shown in 1998 by [[Raúl Rojas]]. He proposed that the tape program would have to be long enough to execute every possible path through both sides of every branch. It would compute all possible answers, but the unneeded results would be canceled out (a kind of [[speculative execution]]). Rojas concludes, "We can therefore say that, from an abstract theoretical perspective, the computing model of the Z3 is equivalent to the computing model of today's computers. From a practical perspective, and in the way the Z3 was really programmed, it was not equivalent to modern computers."<ref name="rojas-ieee" />
+It was possible to construct loops on the Z3, but there was no [[conditional branch]] instruction. Nevertheless, the Z3 was [[Turing-complete]] – how to implement a universal [[Turing machine]] on the Z3 was shown in 1998 by [[Raúl Rojas]]. He proposed that the tape program would have to be long enough to execute every possible path through both sides of every branch. It would compute all possible answers, but the unneeded results would be canceled out (a kind of [[speculative execution]]). Rojas concludes, "We can therefore say that, from an abstract theoretical perspective, the computing model of the Z3 is equivalent to the computing model of today's computers. From a practical perspective, and in the way the Z3 was really programmed, it was not equivalent to modern computers."<ref name="rojas-ieee"/>
-This seeming limitation belies the fact that the Z3 provided a ''practical'' [[instruction set]] for the typical engineering applications of the 1940s.  Mindful of the existing hardware restrictions, Zuse's main goal at the time was to have a workable device to facilitate his work as a [[civil engineer]].<ref name="CPRYq">{{Cite web|url=http://history.computer.org/pioneers/zuse.html|title=My First Computer and First Thoughts About Data Processing|last=Zuse|first=Konrad|date=1987-10-02|website=history.computer.org|series=Computer Pioneers – Konrad Zuse|access-date=2018-05-14}} Search for ''1941''; ["Computer Design-Past, Present, Future," talk in Lund/Sweden, Oct. 2, 1987, previously unpublished.]</ref>
+This seeming limitation belies the fact that the Z3 provided a ''practical'' [[instruction set]] for the typical engineering applications of the 1940s.  Mindful of the existing hardware restrictions, Zuse's main goal at the time was to have a workable device to facilitate his work as a [[civil engineer]].<ref name="CPRYq">{{Cite web |url=http://history.computer.org/pioneers/zuse.html |title=My First Computer and First Thoughts About Data Processing |author-last=Zuse |author-first=Konrad |author-link=Konrad Zuse |date=1987-10-02 |website=history.computer.org |series=Computer Pioneers – Konrad Zuse |access-date=2018-05-14}} Search for ''1941''; ["Computer Design-Past, Present, Future," talk in Lund/Sweden, 1987-10-02, previously unpublished.]</ref>
 == Relation to other work ==
-The success of Zuse's Z3 is often attributed to its use of the simple binary system.<ref name="Ceruzzi" />{{rp|21}} This was invented roughly three centuries earlier by [[Gottfried Leibniz]]; [[Boole]] later used it to develop his [[Boolean algebra (logic)|Boolean algebra]]. Zuse was inspired by [[David Hilbert|Hilbert]]'s and [[Wilhelm Ackermann|Ackermann]]'s book on elementary mathematical logic ''[[Principles of Mathematical Logic]]''.<ref name="hellige-springer" /> In 1937, [[Claude Shannon]] [[A Symbolic Analysis of Relay and Switching Circuits|introduced]] the idea of mapping Boolean algebra onto electronic relays in a seminal work on [[digital circuit]] design. Zuse, however, did not know of Shannon's work and developed the groundwork independently<ref name="kognitive-strukturen" />{{rp|149}} for his first computer [[Z1 (computer)|Z1]], which he designed and built from 1935 to 1938.
+The success of Zuse's Z3 is often attributed to its use of the simple binary system.<ref name="Ceruzzi"/>{{rp|21}} This was invented roughly three centuries earlier by [[Gottfried Leibniz]]; [[Boole]] later used it to develop his [[Boolean algebra (logic)|Boolean algebra]]. Zuse was inspired by [[David Hilbert|Hilbert]]'s and [[Wilhelm Ackermann|Ackermann]]'s book on elementary mathematical logic ''[[Principles of Mathematical Logic]]''.<ref name="hellige-springer"/> In 1937, [[Claude Shannon]] [[A Symbolic Analysis of Relay and Switching Circuits|introduced]] the idea of mapping Boolean algebra onto electronic relays in a seminal work on [[digital circuit]] design. Zuse, however, did not know of Shannon's work and developed the groundwork independently<ref name="kognitive-strukturen"/>{{rp|149}} for his first computer [[Z1 (computer)|Z1]], which he designed and built from 1935 to 1938.
 Zuse's coworker Helmut Schreyer built an electronic digital experimental model of a computer using 100 vacuum tubes<ref name="ZjeJW">[http://www.nue.tu-berlin.de/menue/geschichte/historische_persoenlichkeiten/schreyer "Helmut Schreyer" at the University of Berlin]</ref> in 1942, but it was lost at the end of the war.
-An [[analog computer]] was built by the rocket scientist [[Helmut Hölzer]] in 1942 at the [[Peenemünde Army Research Center]] to simulate<ref name="obituary">[https://query.nytimes.com/gst/fullpage.html?res=9405E5DF1531F93AA35751C0A9679C8B63 H. Otto Hirschler, 87, Aided Space Program]</ref><ref name="wgm1M">{{Cite book|url=https://books.google.com/books?id=L6BfBgAAQBAJ&q=Hoelzer+1942&pg=PT138|title=The Rocket and the Reich: Peenemunde and the Coming of the Ballistic Missile Era|last=Neufeld|first=Michael J.|date=2013-09-10|publisher=[[Smithsonian Institution]]|isbn=9781588344663|page=138|language=en}}</ref><ref name="hoHQm">{{Cite book|url=https://books.google.com/books?id=y1DpBQAAQBAJ&q=Hoelzer+1941&pg=PA38|title=Analog Computing|last=Ulmann|first=Bernd|date=2013-07-22|publisher=[[Walter de Gruyter]]|isbn=9783486755183|page=38|language=en}}</ref> [[V-2 rocket]] trajectories.<ref name="Ja0aX">Neufeld, Michael J (1995). ''The Rocket and the Reich: Peenemünde and the Coming of the Ballistic Missile Era''. New York: The Free Press. p.&nbsp;106.</ref><ref name="2dYy5">{{Cite journal | doi=10.1109/MAHC.1985.10025|title = Helmut Hoelzer's Fully Electronic Analog Computer| journal=IEEE Annals of the History of Computing| volume=7| issue=3| pages=227–240|year = 1985|last1 = Tomayko|first1 = James E.|s2cid = 15986944}}</ref>
+An [[analog computer]] was built by the rocket scientist [[Helmut Hölzer]] in 1942 at the [[Peenemünde Army Research Center]] to simulate<ref name="obituary">[https://query.nytimes.com/gst/fullpage.html?res=9405E5DF1531F93AA35751C0A9679C8B63 H. Otto Hirschler, 87, Aided Space Program]</ref><ref name="wgm1M">{{Cite book |url=https://books.google.com/books?id=L6BfBgAAQBAJ&q=Hoelzer+1942&pg=PT138|title=The Rocket and the Reich: Peenemunde and the Coming of the Ballistic Missile Era |author-last=Neufeld |author-first=Michael J. |date=2013-09-10 |publisher=[[Smithsonian Institution]] |isbn=978-1-58834466-3 |page=138 |language=en}}</ref><ref name="hoHQm">{{Cite book |url=https://books.google.com/books?id=y1DpBQAAQBAJ&q=Hoelzer+1941&pg=PA38 |title=Analog Computing |author-last=Ulmann |author-first=Bernd |date=2013-07-22 |publisher=[[Walter de Gruyter]] |isbn=978-3-48675518-3 |page=38 |language=en}}</ref> [[V-2 rocket]] trajectories.<ref name="Ja0aX">Neufeld, Michael J. (1995). ''The Rocket and the Reich: Peenemünde and the Coming of the Ballistic Missile Era''. New York: The Free Press. p.&nbsp;106.</ref><ref name="2dYy5">{{Cite journal |doi=10.1109/MAHC.1985.10025 |title=Helmut Hoelzer's Fully Electronic Analog Computer |journal=[[IEEE Annals of the History of Computing]] |volume=7 |issue=3 |pages=227–240 |date=1985 |author-last=Tomayko |author-first=James E. |s2cid=15986944}}</ref>
-The [[Tommy Flowers]]-built [[Colossus computer|Colossus]] (1943)<ref name="DQqA3">{{cite book |editor=B. Jack Copeland |title= Colossus: The Secrets of Bletchley Park's Codebreaking Computers |year=2006 |publisher=Oxford University Press |isbn=978-0-19-284055-4}}</ref> and the [[Atanasoff–Berry Computer]] (1942) used [[Thermionic valve|thermionic valves (vacuum tubes)]] and binary representation of numbers. Programming was by means of re-plugging patch panels and setting switches.{{Citation needed|date=May 2021}}
+The [[Tommy Flowers]]-built [[Colossus computer|Colossus]] (1943)<ref name="DQqA3">{{cite book |editor-first=B. Jack |editor-last=Copeland |title=Colossus: The Secrets of Bletchley Park's Codebreaking Computers |date=2006 |publisher=[[Oxford University Press]] |isbn=978-0-19-284055-4}}</ref> and the [[Atanasoff–Berry Computer]] (1942) used [[Thermionic valve|thermionic valves (vacuum tubes)]] and binary representation of numbers. Programming was by means of re-plugging patch panels and setting switches.{{Citation needed|date=May 2021}}
-The [[ENIAC]] computer, completed after the war, used [[vacuum tubes]] to implement switches and used decimal representation for numbers. Until 1948 programming was, as with Colossus, by patch leads and switches.<ref>{{Cite book|last=Haigh|first=Thomas|url=https://www.worldcat.org/oclc/952615433|title=ENIAC in action : making and remaking the modern computer|date=2016|others=Mark Priestley, Crispin Rope|isbn=978-0-262-03398-5|location=Cambridge, Massachusetts ; London, England|pages=113–114|oclc=952615433}}</ref><ref>{{cite web|last=Cruz|first=Frank|date=2013-11-09|title=Programming the ENIAC|url=http://www.columbia.edu/cu/computinghistory/eniac.html|access-date=2016-05-16|website=Programming the ENIAC|publisher=Columbia University}}</ref>
+The [[ENIAC]] computer, completed after the war, used [[vacuum tubes]] to implement switches and used decimal representation for numbers. Until 1948 programming was, as with Colossus, by patch leads and switches.<ref>{{Cite book |author-last=Haigh |author-first=Thomas |url=https://www.worldcat.org/oclc/952615433 |title=ENIAC in action: making and remaking the modern computer |date=2016 |others=Mark Priestley, Crispin Rope |isbn=978-0-262-03398-5 |location=Cambridge, Massachusetts, USA; London, UK |pages=113–114 |oclc=952615433}}</ref><ref>{{cite web |author-last=Cruz |author-first=Frank |date=2013-11-09 |title=Programming the ENIAC |url=http://www.columbia.edu/cu/computinghistory/eniac.html |access-date=2016-05-16 |website=Programming the ENIAC |publisher=Columbia University}}</ref>
-The [[Manchester Baby]] of 1948 along with the [[Manchester Mark 1]] and [[EDSAC]] both of 1949 were the world's earliest working computers that stored program instructions and data in the same space. In this they implemented the [[Von Neumann architecture#Development of the stored-program concept|stored-program concept]] which is frequently (but erroneously) attributed to [[First Draft of a Report on the EDVAC|a 1945 paper]] by [[John von Neumann]] and colleagues.<ref name="pTPDJ">{{cite web |last=von Neumann |first=John |author-link=John von Neumann |title=First Draft of a Report on the EDVAC |year=1945 |url=http://www.virtualtravelog.net/wp/wp-content/media/2003-08-TheFirstDraft.pdf |access-date=March 24, 2014}}</ref><ref name="KtFgF">{{cite encyclopedia |encyclopedia=Encyclopædia Britannica |title=Stored-program concept |url=http://www.britannica.com/EBchecked/topic/567553/stored-program-concept |access-date=24 March 2014}}</ref> Von Neumann is said to have given due credit to [[Alan Turing]],<ref name="4Z0Br">{{cite web |last=Copeland |first=Jack |author-link=Jack Copeland |title=A Brief History of Computing: ENIAC and EDVAC |year=2000 |url=http://www.alanturing.net/turing_archive/pages/Reference%20Articles/BriefHistofComp.html#ACE |access-date=27 January 2010}} which cites {{cite book |last=Randell |first=Brian |author-link=Brian Randell |title=On Alan Turing and the Origins of Digital Computers |editor-last=Meltzer |editor-first=B. |editor2-last=Michie |editor2-first=D. |page=10 |place=Edinburgh |publisher=Edinburgh University Press |journal=Machine Intelligence |volume=7 |year=1972 |isbn=978-0-902383-26-5}}</ref> and the concept had actually been mentioned earlier by Konrad Zuse himself, in a 1936 patent application (that was rejected).<ref name="S1Bmn">{{cite journal |title=Electronic Digital Computers |journal=Nature |date=September 25, 1948 |volume=162 |issue=4117 |page=487 |url=http://www.computer50.org/kgill/mark1/natletter.html |access-date=2009-04-10 |doi=10.1038/162487a0 |url-status=dead |archive-url=https://web.archive.org/web/20090406014626/http://www.computer50.org/kgill/mark1/natletter.html |archive-date=April 6, 2009 |last1=Williams |first1=F. C. |last2=Kilburn |first2=T. |bibcode=1948Natur.162..487W |s2cid=4110351}}</ref><ref name="Kh4rD">Susanne Faber, "Konrad Zuses Bemuehungen um die Patentanmeldung der Z3", 2000</ref> Konrad Zuse himself remembered in his memoirs: "During the war it would have barely been possible to build efficient stored program devices anyway."<ref name="qfA84">{{cite book|first=Konrad|last=Zuse|title=Der Computer – Mein Lebenswerk|location=Berlin|edition=5th|page=78|language=de|isbn=978-3642120954|publisher=Springer|date=20 April 2010|quote=Während des Krieges wäre es freilich ohnehin kaum möglich gewesen, leistungsfähige Geräte mit Speicherprogrammen zu bauen.}}</ref> and [[Friedrich L. Bauer]] wrote: "His visionary ideas (live programs) which were only to be published years afterwards aimed at the right practical direction but were never implemented by him."<ref name="WiPHo">[http://www.horst-zuse.homepage.t-online.de/fiff99-a-2006.pdf Anmerkungen zum John von Neumann Rechner] by [[Horst Zuse]]; F.L. Bauer (original): "Seine erst Jahre später publizierten visionären Ideen (Lebendige Rechenpläne) zielten in die richtige praktische Richtung, wurden von ihm aber nie verwirklicht.</ref>
+The [[Manchester Baby]] of 1948 along with the [[Manchester Mark 1]] and [[EDSAC]] both of 1949 were the world's earliest working computers that stored program instructions and data in the same space. In this they implemented the [[Von Neumann architecture#Development of the stored-program concept|stored-program concept]] which is frequently (but erroneously) attributed to [[First Draft of a Report on the EDVAC|a 1945 paper]] by [[John von Neumann]] and colleagues.<ref name="pTPDJ">{{cite web |author-last=von Neumann |author-first=John |author-link=John von Neumann |title=First Draft of a Report on the EDVAC |date=1945 |url=http://www.virtualtravelog.net/wp/wp-content/media/2003-08-TheFirstDraft.pdf |access-date=2014-03-24}}</ref><ref name="KtFgF">{{cite encyclopedia |encyclopedia=Encyclopædia Britannica |title=Stored-program concept |url=http://www.britannica.com/EBchecked/topic/567553/stored-program-concept |access-date=2014-03-24}}</ref> Von Neumann is said to have given due credit to [[Alan Turing]],<ref name="4Z0Br">{{cite web |author-last=Copeland |author-first=Jack |author-link=Jack Copeland |title=A Brief History of Computing: ENIAC and EDVAC |date=2000 |url=http://www.alanturing.net/turing_archive/pages/Reference%20Articles/BriefHistofComp.html#ACE |access-date=2010-01-27}} which cites {{cite book |author-last=Randell |author-first=Brian |author-link=Brian Randell |title=On Alan Turing and the Origins of Digital Computers |editor-last1=Meltzer |editor-first1=B. |editor-last2=Michie |editor-first2=D. |page=10 |place=Edinburgh, UK |publisher=[[Edinburgh University Press]] |journal=Machine Intelligence |volume=7 |date=1972 |isbn=978-0-902383-26-5}}</ref> and the concept had actually been mentioned earlier by Konrad Zuse himself, in a 1936 patent application (that was rejected).<ref name="S1Bmn">{{cite journal |title=Electronic Digital Computers |journal=Nature |date=1948-09-25 |volume=162 |issue=4117 |page=487 |url=http://www.computer50.org/kgill/mark1/natletter.html |access-date=2009-04-10 |doi=10.1038/162487a0 |url-status=dead |archive-url=https://web.archive.org/web/20090406014626/http://www.computer50.org/kgill/mark1/natletter.html |archive-date=2009-04-06 |author-last1=Williams |author-first1=F. C. |author-last2=Kilburn |author-first2=T. |bibcode=1948Natur.162..487W |s2cid=4110351}}</ref><ref name="Kh4rD">Susanne Faber, "Konrad Zuses Bemuehungen um die Patentanmeldung der Z3", 2000</ref> Konrad Zuse himself remembered in his memoirs: "During the war it would have barely been possible to build efficient stored program devices anyway."<ref name="qfA84">{{cite book |author-first=Konrad |author-last=Zuse |author-link=Konrad Zuse |title=Der Computer – Mein Lebenswerk |location=Berlin, Germany |edition=5th |page=78 |language=de |isbn=978-3-64212095-4 |publisher=Springer |date=2010-04-20 |quote=Während des Krieges wäre es freilich ohnehin kaum möglich gewesen, leistungsfähige Geräte mit Speicherprogrammen zu bauen.}}</ref> and [[Friedrich L. Bauer]] wrote: "His visionary ideas (live programs) which were only to be published years afterwards aimed at the right practical direction but were never implemented by him."<ref name="WiPHo">[http://www.horst-zuse.homepage.t-online.de/fiff99-a-2006.pdf Anmerkungen zum John von Neumann Rechner] by [[Horst Zuse]]; F. L. Bauer (original): "Seine erst Jahre später publizierten visionären Ideen (Lebendige Rechenpläne) zielten in die richtige praktische Richtung, wurden von ihm aber nie verwirklicht.</ref>
 == Specifications ==
-* Average calculation speed: addition – 0.8 seconds, multiplication – 3 seconds<ref name="Morelli">{{cite book|last1=Morelli|first1=Marcello|title=Dalle calcolatrici ai computer degli anni Cinquanta|date=2001|publisher=FrancoAngeli|isbn=9788846428790|page=177|url=https://books.google.com/books?id=p5GszzXR550C&pg=PA177|access-date=5 August 2014}}</ref>
+* Average calculation speed: addition – 0.8 seconds, multiplication – 3 seconds<ref name="Morelli">{{cite book |author-last=Morelli |author-first=Marcello |title=Dalle calcolatrici ai computer degli anni Cinquanta |date=2001 |publisher=FrancoAngeli |isbn=978-8-84642879-0 |page=177 |url=https://books.google.com/books?id=p5GszzXR550C&pg=PA177 |access-date=2014-08-05}}</ref>
 * Arithmetic unit: Binary [[floating-point]], 22-bit, add, subtract, multiply, divide, square root<ref name="Morelli" />
-* Data memory: 64 words with a length of 22 bits<ref name="Morelli" />
+* Data memory: 64 words with a length of 22 bits<ref name="Morelli"/>
-* Program memory: Punched celluloid tape<ref name="Morelli" />
+* Program memory: Punched celluloid tape<ref name="Morelli"/>
-* Input: Decimal floating-point numbers<ref name="Morelli" />
+* Input: Decimal floating-point numbers<ref name="Morelli"/>
-* Output: Decimal floating-point numbers<ref name="Morelli" />
+* Output: Decimal floating-point numbers<ref name="Morelli"/>
-* Input and Output was facilitated by a terminal, with a special keyboard for input and a row of lamps to show results<ref name="autogenerated1" />
+* Input and Output was facilitated by a terminal, with a special keyboard for input and a row of lamps to show results<ref name="autogenerated1"/>
-* Elements: Around 2,000 relays (1,400 for the memory)<ref name="autogenerated1" />
+* Elements: Around 2,000 relays (1,400 for the memory)<ref name="autogenerated1"/>
-* Frequency: 5–10 hertz<ref name="Morelli" />
+* Frequency: 5–10 hertz<ref name="Morelli"/>
-* Power consumption: Around 4,000 watts<ref name="Morelli" />
+* Power consumption: Around 4,000 watts<ref name="Morelli"/>
-* Weight: Around {{convert|1|t|lb}}<ref name="Morelli" />
+* Weight: Around {{convert|1|t|lb}}<ref name="Morelli"/>
 == Modern reconstructions ==
 [[File:Finder Relais Zuse Z3.jpg|thumb|Z3 reconstruction in 2010 by Horst Zuse]]
-A modern reconstruction directed by [[Raúl Rojas]] and [[Horst Zuse]] started in 1997 and finished in 2003. It is now in the Konrad Zuse Museum in Hünfeld, Germany.<ref name="LMSxR">{{cite web |title=Reconstruction of Konrad Zuse's Z3 Computer {{!}} Raúl Rojas |url=http://dcis.inf.fu-berlin.de/rojas/reconstruction-of-konrad-zuses-z3-computer/ |website=dcis.inf.fu-berlin.de}}</ref><ref name="snbXk">{{cite web |title=Reconstructing the calculating machine Z3 |url=http://zuse.zib.de/reconstructionZ3|website=zuse.zib.de}}</ref> Memory was halved to 32 words. Power consumption is about 400 W, and weight is about {{Convert|30|kg|lb}}.<ref name="qEXYi">{{cite web|url=http://www.horst-zuse.homepage.t-online.de/z3-nachbau-2001.html|title=Z3-Nachbau-2001|website=www.horst-zuse.homepage.t-online.de|language=de|trans-title=Z3 replica 2001}} ([https://translate.google.com/translate?sl=auto&tl=en&js=y&prev=_t&ie=UTF-8&u=http%3A%2F%2Fwww.horst-zuse.homepage.t-online.de%2Fz3-nachbau-2001.html&edit-text= Google translation])</ref>
+A modern reconstruction directed by [[Raúl Rojas]] and [[Horst Zuse]] started in 1997 and finished in 2003. It is now in the Konrad Zuse Museum in Hünfeld, Germany.<ref name="LMSxR">{{cite web |title=Reconstruction of Konrad Zuse's Z3 Computer |author-first=Raúl |author-last=Rojas |url=http://dcis.inf.fu-berlin.de/rojas/reconstruction-of-konrad-zuses-z3-computer/ |website=dcis.inf.fu-berlin.de}}</ref><ref name="snbXk">{{cite web |title=Reconstructing the calculating machine Z3 |url=http://zuse.zib.de/reconstructionZ3 |website=zuse.zib.de}}</ref> Memory was halved to 32 words. Power consumption is about 400&nbsp;W, and weight is about {{Convert|30|kg|lb}}.<ref name="qEXYi">{{cite web |url=http://www.horst-zuse.homepage.t-online.de/z3-nachbau-2001.html |title=Z3-Nachbau-2001 |website=www.horst-zuse.homepage.t-online.de |language=de |trans-title=Z3 replica 2001}}</ref>
-In 2008, Horst Zuse started a reconstruction of the Z3 by himself.<ref name="TnNVK">{{Citation|last=Zuse|first=Horst|title=Reconstruction of Konrad Zuse's Z3|volume=416|date=2013|work=Making the History of Computing Relevant|pages=287–296|publisher=Springer Berlin Heidelberg|language=en|doi=10.1007/978-3-642-41650-7_26|isbn=9783642416491|series=IFIP Advances in Information and Communication Technology|doi-access=free}}</ref> It was presented in 2010 in the Konrad Zuse Museum in Hünfeld.<ref name="Oe8xY">{{Cite web|url=http://www.horst-zuse.homepage.t-online.de/horst-zuse-zuse-jahr-2010-html/english/veranstaltung.html|title=Events during Zuse Year 2010|last=Zwernemann-Blech|first=Irene|website=www.horst-zuse.homepage.t-online.de|access-date=2018-11-03}}</ref><ref name="SLUQC">{{Cite web|url=http://www.horst-zuse.homepage.t-online.de/horst-zuse-z3-html/z3-vermarktung.html|title=Z3-Präsentationen|website=www.horst-zuse.homepage.t-online.de|language=de|trans-title=Z3 – Presentations|access-date=2018-11-03}} ([https://translate.google.com/translate?sl=auto&tl=en&u=http%3A%2F%2Fwww.horst-zuse.homepage.t-online.de%2Fhorst-zuse-z3-html%2Fz3-vermarktung.html Google translation])</ref>
+In 2008, Horst Zuse started a reconstruction of the Z3 by himself.<ref name="TnNVK">{{Citation |author-last=Zuse |author-first=Horst |author-link=Horst Zuse |title=Reconstruction of Konrad Zuse's Z3 |volume=416 |date=2013 |work=Making the History of Computing Relevant |pages=287–296 |publisher=Springer Berlin Heidelberg |language=en |doi=10.1007/978-3-642-41650-7_26 |isbn=978-3-64241649-1 |series=IFIP Advances in Information and Communication Technology |doi-access=free}}</ref> It was presented in 2010 in the Konrad Zuse Museum in Hünfeld.<ref name="Oe8xY">{{Cite web |url=http://www.horst-zuse.homepage.t-online.de/horst-zuse-zuse-jahr-2010-html/english/veranstaltung.html |title=Events during Zuse Year 2010 |author-last=Zwernemann-Blech |author-first=Irene |website=www.horst-zuse.homepage.t-online.de |access-date=2018-11-03}}</ref><ref name="SLUQC">{{Cite web |url=http://www.horst-zuse.homepage.t-online.de/horst-zuse-z3-html/z3-vermarktung.html |title=Z3-Präsentationen|website=www.horst-zuse.homepage.t-online.de |language=de |trans-title=Z3 – Presentations |access-date=2018-11-03}}</ref>
 ==See also==
@@ Line 78: / Line 77: @@
 == References ==
-{{reflist|colwidth=30em}}
+{{reflist}}
 == Further reading ==
-* {{cite book |editor=B. Jack Copeland |title= Colossus: The Secrets of Bletchley Park's Codebreaking Computers |year=2006 |publisher=Oxford University Press |isbn= 978-0-19-284055-4}}
+* {{cite book |editor-first=B. Jack |editor-last=Copeland |title=Colossus: The Secrets of Bletchley Park's Codebreaking Computers |date=2006 |publisher=[[Oxford University Press]] |isbn=978-0-19-284055-4}}
-* {{cite journal |author1=R. Rojas |author2=F. Darius |author3=C. Göktekin |author4=G. Heyne  |name-list-style=amp |title=The reconstruction of Konrad Zuse's Z3| journal=IEEE Annals of the History of Computing| volume=27| issue=3| pages=23–32 |year=2005 | doi=10.1109/mahc.2005.48|s2cid=16288658 }}
+* {{cite journal |author-first1=Raúl |author-last1=Rojas |author-link1=Raúl Rojas |author-first2=F. |author-last2=Darius |author-first3=C. |author-last3=Göktekin |author-first4=G. |author-last4=Heyne |title=The reconstruction of Konrad Zuse's Z3 |journal=[[IEEE Annals of the History of Computing]] |volume=27 |issue=3 |pages=23–32 |date=2005 |doi=10.1109/mahc.2005.48 |s2cid=16288658}}
 == External links ==