Oprema – 2019AUG26 The Relay Computer of Carl Zeiss Jena
Jürgen F. H. Winkler Friedrich Schiller University, Jena
The Oprema (Optikrechenmaschine = computer for optical calculations) was a relay computer whose development was initiated by Herbert Kortum and which was designed and built by a team under the leadership of Wilhelm Kämmerer at Carl Zeiss Jena (CZJ) in 1954 and 1955. Basic experiments, de‐ sign and construction of machine‐1 were all done, partly concurrently, in the remarkably short time of about 14 months. Shortly after the electronic G 2 of Heinz Billing in Göttingen it was the 7th universal computer in Germa‐ ny and the 1st in the GDR. The Oprema consisted of two identical machines. One machine consisted of about 8,300 relays, 45,000 selenium rectifiers and 250 km cable. The main reason for the construction of the Oprema was the computational needs of CZJ, which was the leading company for optics and precision me‐ chanics in the GDR. During its lifetime (1955−1963) the Oprema was applied by CZJ and a number of other institutes and companies in the GDR. The paper presents new details of the Oprema project and of the arithmetic operations implemented in the Oprema. Additionally, it covers briefly the lives of the two protagonists, W. Kämmerer and H. Kortum, and draws some comparisons with other early projects, namely Colossus, ASCC/Mark 1 and ENIAC. Finally, it discusses the question, whether Kortum is a German com‐ puter pioneer.
Pre-history in Jena (CZJ) and became a member of Kortum’s At the beginning of the 20th century, three people development lab3. At the end of the war he re- were born, who were to play an important role in turned to Naumburg/Saale and took up work again the history of computing in Germany. Wilhelm as a high school teacher for about one year. On 1 Kämmerer was born on 23 July 1905 in Büdingen, June 1946 he joined CZJ again.4 a small town north-east of Frankfurt/Main; Herbert Kortum studied physics at today’s Friedrich Franz Kortum was born on 15 September 1907 in Schiller University (FSU) in Jena from 1926 to Gelting, near Schleswig in the northern part of 1930, obtained a PhD in Physics in 1930 and then Germany, and Konrad Ernst Otto Zuse was born worked as an assistant professor at the Institute of on 22 June 1910 in Berlin. Physics at the same university.5 In 1934 Kortum Zuse was not directly involved in the activities left the university and joined CZJ, which was one around the Oprema, but his person can serve as a of the leading optical companies worldwide. His kind of reference point in the history of computing first project was “Entwicklungsarbeiten an Re- in Germany, as on 12 May 1941 he presented the chengeräten für die Feuerleitung unter Ver- first program-controlled computer, the Z3, in wendung elektromechanischer Analogre- Berlin to visitors from the German Aeronautics chenglieder und Servosysteme [Development of Research Institute.1 Moreover, indirect connec- computational devices for fire control using ana- tions between the Oprema, Kämmerer, Kortum logue computing elements and servo systems]“.6 and Zuse existed during the development period In 1939 Kortum became the co-head of the reor- and later after the reunification of Germany. ganized Telegroup, the development lab for field Kämmerer studied mathematics at Gießen and glasses and other optical equipment for military Göttingen, obtained a PhD in mathematics from use7, which was then called KoKor (Kon- the university of Gießen in 1927, and, in 1929, struktionsbüro Kortum [Development Lab Kor- became a high school teacher of mathematics in tum]).8 This lab also developed sophisticated Naumburg/Saale, in the central part of Germany.2 electro-mechanical targeting devices for Luftwaffe In 1943 Kämmerer joined the Carl Zeiss Company bombers including the Lotfe 7D bombsight, which
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 1 Kurowski calls “a miracle of technology”, and the Schumann reports that Lieutenant Colonel TSA (Tief- und Sturzanlage [level- and dive- Urmajeff had visited him on that day and had bombing aiming device]). Kortum’s work also asked about the Oprema. Schumann had answered became known in the USA. On 13 April 1945 US that “Oprema” was currently more an idea and by troops entered Jena and also took command at far not a mature project. Urmajeff asked again on CZJ. The US specialists were especially interested 6 Nov. 1945 and Schumann gave exact the same in the aerial cameras and the aiming devices. answer, that “Oprema” was rather an idea than a Kortum was interrogated by Captain James Harris project.16 about the TSA in late April or early May 1945. It The next hint on the Oprema occurs in the is interesting to note that the Germans learned minutes of a meeting on 17 Aug. 1946 attended by about dive-bombing from the Americans when Major Turügin, Major Jachantoff, Dr. Tiedeken, Ernst Udet, who was a notable flying ace of World Schumann and Dr. Kortum. Kortum made a short War I, visited the National Air Races in Los Ange- statement about the plans for the development of a les in 1928 and later saw the Curtiss Hawk F8C computer for optical calculations based on the (“Helldiver”) at the Curtiss airfield on 27 Septem- components that had been developed by EBo 5 ber 1933.9 When the US military left CZJ and Jena (Entwicklungsbüro 5 [development lab no. 5]). at the end of June 1945, they took, amongst other Since July 1945 “EBo 5” was the name of Kor- people and things, Kortum and his family with tum’s former development lab “KoKor”. The them and brought them to Heidenheim in southern components were those of the bombsights and Germany.10 In October 1945 he was still impris- other devices that had been developed there during oned there.11 the preceding years. These components were In Jena the Soviets took command at CZJ on 1 elements of analogue computation techniques. July 1945. Karl Schumann became the new head Kortum said that he could not give any details of KoKor.12 The Soviets were also very eager to because this was a project still in its infancy, and learn about the devices that had been developed by that a lot of theoretical work had to be done before KoKor. In a memo Schumann reports that Lieu- a design could begin. First of all, he needed a tenant Colonel Urmajeff was very interested in a scientist of suitable background and experience. high-precision gyroscope, a prototype of which Major Turügin asked for a more detailed written had been built in 1940 on Kortum’s order. report explaining how Kortum thought this project Urmajeff remarked that such devices would be would proceed. This report was to be delivered by quite important for Russian aircrafts when they 21 Aug. 1946. In a later meeting with Major Gen- had to fly over the vast lands of northern Siberia or eral Nikolaew it was decided that Kortum’s report over the North Pole to America.13 would be handed in later because at that time At the beginning of 1946, Kortum returned to Kortum was apparently very busy and over- Jena without his family, which was staying in whelmed with work (see e.g. the experiments near Königsbronn near Heidenheim. The exact date of Jüterbog mentioned above).17 his return is somewhat unclear, different dates are Later in the meeting with Major Turügin on 17 mentioned in different sources. The most precise Aug. 1946, Dr. Tiedeken presented his idea to use primary source is a memo of Schumann dated 12 Hollerith machines for computations required for February 1946. In this memo Schumann reports the design of optical systems. He said that he had that Major Gleinick and First Lieutenant Chorol already contacted the Hollerith company and had had visited him on that day. They had said that received a positive response. The “Hollerith com- they would come again on 13 February and had pany“ must have been the DEHOMAG (Deutsche asked that Dr. Kortum should then explain the Hollerith-Maschinen Gesellschaft mbH [German complete structure of the TSA. These circum- Hollerith Machines Company Ltd.]) that was stances suggest that Kortum was back in Jena not founded on behalf of Herman Hollerith on 30 Nov. later than 12 February 1946.14 1910 and that had restarted the production of During 1945 and 1946 the Soviets were quite punched-card machines in Berlin in Oct. 1945.18 interested in the bombsights, that had been devel- Dr. Tiedeken was a scientist in the lab for the oped by KoKor, and wondered how they could calculations for photographic lenses.19 make use of them for their own aircrafts. In Au- But these plans and ambitions came to a sud- gust and September 1946 e.g., Kortum did exper- den halt on 22 Oct. 1946. In the early morning of iments near Jüterbog, south of Berlin, with aiming that Tuesday the Operation Osoaviakhim was put devices mounted on Soviet army airplanes.15 into action. All over the Soviet Occupation Zone Soviet officers, accompanied by a group of sol- History diers, were knocking on the doors of several thou- How the idea for the Oprema (Optikre- sand scientists, engineers, technicians and skilled chenmaschine = computer for optical calculations) workers employed in war-related industries. The evolved and who came up with the idea first is officer read out an order of the Soviet Military unknown. None of those involved, who are now Administration that the resp. person had to do all dead, has left any description of this process. professional work in the Soviet Union (SU) under The first primary source that mentions the Oprema comparable conditions as their Soviet counterparts is a memo by Schumann dated 2 Nov. 1945. for 5 years, and that he could take with him his
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 2 wife, children and as much of his belongings as he bracht, wir hätten diese Entwicklung bereits fertig wanted.20 In Jena 276 personnel from Zeiss alone in der Tasche aus der SU mitgebracht. Dazu sei were thus deported to different locations in the SU, festgestellt, daß dies eine freie Erfindung der among them Kämmerer, with his wife and two Urheber dieser Version ist, insofern, als wir uns daughters, and Kortum, without his family which hinsichtlich dieses Themas während unseres was still in the American Occupation Zone. Aufenthaltes in der SU zwar durch Litera- Kämmerer even took his Steinway Concert Grand turstudien laufend über die in der Welt vorge- with him (and in 1953 back) and Kortum his vio- gangene Entwicklung informieren konnten und lin. In the following years, the group around Kor- insofern allerdings die nötigen Fachkenntnisse und tum and Kämmerer (K&K) lived at several places konkrete Vorstellungen zur Lösung der gestellten mostly near Moscow: Mamontowka (Nov. 1946 – Aufgabe mitbrachten, wir hatten aber weder Zeit Nov. 1948), Moscow-Sokolniki (Nov. 1948 – Jan. noch Gelegenheit, konkrete Vorarbeiten dazu 1952), Krasnogorsk (Jan. 1952 – Jun. 1952), Go- durchzuführen und mitzunehmen. Es ist daher die rodomlia (Jun. 1952 – Nov. 1953). Instead of 5 Wahrheit, daß Entwicklung, Bau und Montage der years they had to stay 7 years in the SU.21 gesamten Anlage mit allen dazu nötigen Arbeiten K&K gave no details about the kind of work im Jahre 1954 durchgeführt worden sind. they had to do in those years. It may be assumed [When the plan [to build the Oprema; JW] had that, before they could return to Germany, they really been realized and, several days before the had to sign a formal declaration of obligation not end of the year, the two machines could be pre- to tell anybody about their work in the SU, simi- sented as completely assembled, and the costs larly as the rocket scientist Kurt Magnus had to do. were as expected, a lot of people spread the rumor After the German Reunification Kämmerer wrote: that we had brought the complete plans of the “Unsere Tätigkeit bestand im wesentlichen darin, Oprema with us when we returned from the SU. unsere Arbeitsmethoden und Erfahrungen an This, I must say, is a free invention by the initia- sowjetische Ingenieure zu übertragen [Our work tors of this rumor. It is true that during our stay in essentially was to transfer our methods and experi- the SU we could indeed study the literature and ence to Soviet engineers]”. Other sources say that thus follow the worldwide developments. There- the Kortum group worked on bombsights as it had fore, we came back with the know-how and the done in the preceding years at CZJ. This would be concrete ideas necessary for the solution of this analogous to what the rocket scientists Werner task. But we neither had the time nor the oppor- Albring and Magnus or the physicist Kurt Berner tunity to do any specific preliminary works, so we reported about their stay as “specialists” in the SU. could have brought the results back with us. It is To my knowledge none of the Zeiss people has therefore the truth that the development and con- published anything similar to the reports of Al- struction of the whole system and all the activities bring, Berner and Magnus. A similar observation necessary for them were done in 1954].”24 has been made independently by Matthias Uhl.22 Helga Kämmerer also reports that all the The detention on the small island of Gorodom- knowledge of K&K about western computers lia in Lake Seliger, halfway between Moscow and came from broadcasts of the BBC, which came in Leningrad (now St. Petersburg again), was, by the rather weakly.25 This does not correspond to Kor- Soviet authorities, intended to be a cooling-off tum’s statement mentioned above. She gives no period, during which the scientists should “forget” further details about these broadcasts, e.g. the time the details of the work they had done before. Kor- or to which specific World Service of the BBC tum, Kämmerer and the other Zeiss scientists (e.g. German, English, Russian) they had listened. were completely isolated on this small island. It seems that we can rule out that K&K heard the There was no scientific or even belletristic litera- five broadcasts on “Automatic Calculating Ma- ture. The only books they had were those they had chines” which were broadcast on BBC’s Third brought with them in October 1946. When they Programme radio service in May and June 1951. left Krasnogorsk they had to leave behind all The Third Programme, started on 29 September papers, notes, even letters they had received from 1946, was a home service, which was barely re- relatives in Germany; it all was burned.23 ceived in the whole country. In April 1951 “The Helga Kämmerer reports that during their stay Third’s coverage was now estimated to have in- on Gorodomlia K&K, who had no official work to creased to between sixty-five and seventy percent do, discussed their ideas for the Oprema. But of the population, . . .“26 unfortunately no direct statement by them seems to The Zeiss people on Gorodomlia were allowed exist on these discussions. In a report dated May to leave the SU in November 1953 and arrived in 1958, Kortum states: Jena on 21 November 1953, where they were “Als dann aber tatsächlich der Plan realisiert received by their Zeiss colleagues in the hall of wurde und einige Tage vor Jahresende die beiden mirrors of the hotel “Schwarzer Bär [Black Bear]”. Maschinen mit Kosten, die mit den geplanten On 22 November they joined CZJ again. Kortum Kosten in guter Übereinstimmung waren, fertig then took a convalescent leave and started work as montiert vorgestellt werden konnten, wurden Chief of Development on 21 January 1954.27 [wurde; JW] von vielen Seiten die Version aufge-
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 3 Fig. 1. Wilhelm Kämmerer. Fig. 2. Herbert Franz Kortum. Courtesy of Helga Kämmerer. Courtesy of Helga Kämmerer. Design and Construction of the Oprema 1954. Arbeitsberichte During the winter 1953/54, K&K visited Nikolaus 5.4. Arbeitsbeginn. Allgemeine Einführung und Joachim Lehmann at the Dresden Institute of Auftrag zur Konstruktion der „Re- Technology. Lehmann, a young physicist, had chenmaschine für optische Rechnungen.” started a small project to develop an electronic Bespr. bei Dr. Kämmerer. Relaismaschine computer after he had read the paper on ENIAC in Zu Kontrollzwecken als Zwillingsmaschine MTAC July 1946, which had reached him only in ausgeführt. Rechnet im Dualsystem. Aufbau early spring 1948! No details of this meeting are des Gerätes in grossen Zügen. reported, neither in the papers of K&K nor in Dualsystem mit Aiken Verschlüsselung. . . . Lehmann’s papers in the archives of the Deutsche [1954. Work Reports Museum in Munich. Since Lehmann’s computer 5.4. Work begins. General introduction and was expected to be ready only in late 1955, K&K assignment for the design of the “Calculating started their own computer project at CZJ.28 Machine for Optical Calculations.” Meetg. at The first document of this phase of the Opre- Dr. Kämmerer’s. Relay machine For check- ma story is the first entry in Gerhard Lenski’s ing purposes conceived as twin-machine. work diary dated 5 April 1954. This handwritten Computes with the binary system. Broad diary does not bear his name, but his role as head outline of the device. Binary system using of physical design and construction, his handwrit- the Aiken code. . . .]”29 ing, the attribution by Edgar Mühlhausen in his During the first five weeks there were almost daily paper “Am Anfang war OPREMA . . . [In the meetings at Kämmerer’s office. The LWD shows Beginning was the OPREMA . . .]”, and, last but that Kämmerer already had quite detailed ideas not least, the very contents of this document make about the computer. The computer was to be based the authorship of Lenski quite certain. Mühlhausen on relays and to use a BCD (binary coded decimal) joined the Oprema project on 6 September 1954, number representation. The program and input right after he had finished his studies of mechani- numbers were to be be stored in plugboards. The cal and electrical engineering at the Dresden Insti- plugboards were to be permanently installed. Each tute of Technology. Lenski’s work diary (LWD) instruction and input number was to occupy one covers the time from 5 April to 24 December 1954 row of the resp. plugboard. The loading of a and is 58 pages long. It contains entries for all program and the input numbers had to be done by working days of that period, i.e. all days except putting plugs into certain sockets, where each such Sundays and holidays because at that time Satur- plug-socket pair corresponded to one bit. Lenski day was a regular work day in the GDR. The only proposed to use switches instead of the plug- Saturday without an entry is the Saturday before socket pairs. Kämmerer refused because he wanted Easter. to use plugging templates in order to facilitate the LWD begins as follows: “ loading of programs, which is a rather error-prone
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 4 process. Kämmerer also had detailed ideas about Kämmerer had already done some significant the logical structure, the principles of control, the design work before April 1954, especially after his instruction format, and the number format. return to Jena on 21 November 1953.31 Whether The instruction format was as follows: any important design work had been done before Adr1(6) Op(6) Adr2(6) Adr3(5) Adr4(4) that date back in the Soviet Union is currently unclear and has already been discussed above in where the numbers in parentheses are the number the context of Kortum’s report of May 1958. of bits of the corresponding part of the instruction. In April 1954 work on the Oprema started on a One instruction therefore consisted of 27 bits. rather small scale involving only a handful of More details about the instruction code are given persons. Nevertheless, by mid-May the overall below in the section on the technical properties of design and respective designs for the adder, the the Oprema. control pyramid, the control matrix, the command Numbers were to be stored as floating-point chain, the instruction processing and for the input numbers in binary coded decimal form in the and output process had been drawn up. Since all following format: arithmetic operations were to be based on the S DDDDDDDD S E addition operation the adder was the central part of where the arithmetic unit. The output was to be printed - S is a sign (+ or −, 1 bit), on a modified electrical typewriter. Additionally, a - D is a binary coded decimal digit of the signifi- plan of the physical layout, and, especially for a cand (4 bit), meeting in Berlin, a schedule and a cost estimate - E is the binary coded exponent (4 bit). had been prepared. Kämmerer calls the significand the “Mantisse The next important event in the history of the [mantissa]” of the floating point number, whereas Oprema was a meeting at the Ministerium für I follow the IEEE and ISO standards and use the Maschinenbau [Ministry of Machine Building] in term “significand”. Donald E. Knuth criticized the East Berlin on 17 Mai 1954. Minister Heinrich use of the term “mantissa” in this context: “but it Rau had summoned Dr. Hugo Schrade, the plant is an abuse of terminology to call the fraction part manager of CZJ, and Dr. Kortum, the Head of a mantissa, since this concept has quite a different Development. Rau first demanded that CZJ should meaning in connection with logarithms.” Interest- produce 100 exemplars of the newly developed ingly, in the paper “Oprema, die programmges- photocolposcope model in due time for the Leipzig teuerte Zwillingsrechenanlage … [Oprema, the Trade Fair. Additionally, Rau expressed his wor- program-controlled twin-computer …]” the term ries about the insufficient plan fulfillment at CZJ. mantissa is always written in quotation marks as After the discussion of some further problems CZJ „Mantisse‟. It seems, that Kämmerer as a mathe- had with the authorities, Kortum presented his matician was aware of the problem mentioned by proposal, based on plans prepared during the Knuth. preceding months, for building the Oprema, which would be able to do the work of at least 120 hu- As mentioned above, the Aiken code was to be man computers. As motivation he mentioned that used for the digits of the significand, but on Tues- large-scale computers had already been in use (in day 24 April 1954 it was decided to use the ex- some cases for several years) in other countries cess-3 code instead, because this led to a lower (America, Sweden, Switzerland, the UK). He load of the relay contacts. pointed out that some rival firms had already been On the quantitative side Kämmerer’s plans for using automatic computers for several years and one machine envisaged: gave two special examples: - 5 plugboards with a total of 200 rows à 40 sock- - the Leitz company in Wetzlar, well-known for ets for the input numbers, the Leica camera, had recently installed the Zuse - approx. 6,000 relays and 20,000 rectifiers, Z5 computer; - 442 lamps, 300 push-buttons and 300 switches - the Swiss company Wild at Heerbrugg had re- at the console. (LWD 6 and 8 April) cently presented a new lens for aerial cameras, LWD contains no estimation for the number of the Aviogon, which had been designed by Lud- program plugboards and their rows. wig Bertele, who might have used the “computer The final figures for one machine were: installed in Zurich” for the necessary computa- 32 - 6 plugboards with a total of 300 rows à 27 sock- tions. ets for the program, Leitz had ordered the Z5, a relay computer, - 1 plugboard with 28 rows à 39 sockets for input from Konrad Zuse in 1950 and it was delivered to Wetzlar on 7 July 1953. numbers, th - 4 plugboards with a total of 320 rows à 41 sock- Wild had presented the Aviogon at the 7 ets for input numbers, International Symposium on Photogrammetry - 8313 relays and approx. 45,000 rectifiers. 1952 in Washington, and it had impressed the specialists of CZJ very much. The developer of the The available documents contain no figures on Aviogon was Ludwig Bertele, whom the Zeiss the final numbers of lamps and switches at the 30 people knew quite well because he had worked for console. Zeiss Ikon in Jena and Dresden between 1926 and
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 5 1942. He was one of the most outstanding lens 28 September 1954, Lenski begins to record the designers in the world. Kortum said that he as- end of his daily work, too: “7 00 − 18 30”. From 11 sumed Bertele had used the “machine installed in to 20 November it is mostly 07:00 to 19:00, from Zürich” for the development of the Aviogon. The Monday 22 November to 10 December 07:00 to “machine installed in Zürich” is obviously Zuse’s 22:00, and, finally, from 13 to 24 December 06:30 Z4. An attempt to verify Kortum’s conjecture to 23:30. These figures differ somewhat from a produced a negative result; no information on any statement by Lenski made in a TV interview: “Ab use of the Z4 by Bertele could be found.33 Ende Mai Tag und Nacht gearbeitet [From the end Kortum’s presentation seems to have con- of May we worked day and night]”. On a list, in vinced minister Rau and he immediately allotted 1 which Lenski recorded the overtime done by Mio. DM34 from the fund for rationalization to this different people, he states 373.5 hours of overtime project. In return, Kortum promised to complete during 10 months for himself.38 the machine by the end of 1954. This meeting took The last entry in LWD reads: “ a similar course as a meeting at the Ballistic Re- 20.12– 24.12 An der Maschine schliesst sich ein search Laboratory (BRL) at Aberdeen Proving 6 30 − 2330 Loch nach dem andern Relaisplat- Ground on 9 April 1943: John G. Brainerd, John ten sind alle eingebaut. Steckertafeln fehlen nur Mauchly and J. Presper Eckert of the Moore noch ungefähr. 17 Stück, die nun aber auch schon School of the University of Pennsylvania had fertig sind. Der Impulsgeber läuft ohne Prellungen. visited Colonel Leslie Simon, the director of BRL, Er ist in 3 Nächten hinjustiert worden. Das Schalt- and had presented the ENIAC proposal. “The pult ist bis auf eine Platte auch fertig. Die same day, Simon, convinced that the bold project Ladegleichrichter und Quecksilberrelais sind was of extreme importance, gave his support and eingetroffen und werden eingebaut. [ promised to include the project in his budget.”35 20.12– 24.12 At the machine gap after gap is On 18 May 1954, the day after the meeting in 6 30 − 2330 being closed All relay plates have Berlin, Lenski writes in LWD: “Bespr. Kortum. been mounted. Only approx. 17 plugboards are Mitteilung dass Bau der Maschine genehmigt ist. missing, but they have already completed now. Sofort mit Arbeit im Grossen anfangen. [Meetg. The pulse generator runs without bounces. It has Dr. Kortum. Announcement that construction of been adjusted during 3 nights. Except for one the machine has been approved. Immediately plate, the console is also complete. The charging going to begin with the work on a large scale.]”. rectifiers and the mercury relays have arrived and During the following months the workforce they are now being installed.]” working on the Oprema grew steadily and reached On Thursday, 30 December 1954, one day its highest number on 17 December, when e.g. 2 before the deadline, CZJ reported the completion shifts of about 7 persons each worked on the cable of the Oprema to minister Rau. Kämmerer himself harnesses, alone. The last but one cable harness later stated that at the end of 1954 the Oprema was was completed on 17 December. Eberhard Die- “im Bau vollendet [construction was completed]”, tzsch, a former lens designer at CZJ, who had and that during the debugging of machine-2 in joined CZJ as a computer in 1954, recalls that he 1955 they found 452 faults, among them 123 and his colleagues were released from their com- missing wires or rectifiers and 47 cold solder putational duties in December and then also joints.39 worked on the cable harnesses during the grave- On Wednesday, 5 Jan. 1955, the Under Secre- yard shift.36 Beginning on 13 December soldering tary in the Department for Machine Building, was also done in two shifts. For several weeks Helmut Wunderlich, visited CZJ, and, as part of before 17 December, 8 switchboard people and this visit, K&K proudly showed him the Oprema. even 10 people from the payroll office worked on On the pictures taken at this event, the Oprema the Oprema from 15:00 to 22:00, after their regular looks quite complete, at least as seen from the daily working hours. Lenski gives no exact figures outside. The end of the main construction phase on the workforce involved, but the number of was celebrated with a party at the trade union people invited to the Oprema Party on the evening building on the evening of Saturday, 8 Jan. 1955. of Saturday, 8 January 1955, was about 260. This Approximately 250 people attended. Someone figure includes some high-level managers and also even composed a poem for this event: people which did not work directly on the Oprema but provided material and component parts. On “Oprema ‒ Ballade ! three lists, 80 persons are mentioned eligible to different kinds of bonuses.37 Durch die Hallen von Oprema, During 1954 not only the work force but also ziehn die Hirten morgens an ihren Platz the daily working hours grew steadily. On Thurs- und sie schuften an den Platten day, 5 August, Lenski begins to record the time he als wenn’s ging um einen großen Schatz. starts work in the morning: “Anf. 7.30 [Beg. 7.30]“. Selbst die Herren Konstrukteure From 6 August to 28 September he begins at 07:00 wissen auch bald nicht mehr ein noch aus and from 29 September to 20 October at 06:30. On sie zerbrechen sich die Köpfe, 21 October he returns to 07:00 and from 13 to 24 wenn es sein muß noch zu Haus. December he begins at 06:30 again. On Tuesday,
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 6 Refrain: Brainerd was the supervisor in responsible charge Tralla, tralla of the ENIAC project at the Moore School of Prima, prima, beinah wie Oprema, UPenn. das baut man in Jena In 1999, Mühlhausen, who joined the Oprema trallalala. project in autumn 1954, mentions the following people, who made important contributions to the Oprema hat es in sich, creation of Oprema: Hans Dietrich, Alfred Jung, das weiß ein jeder hier, Gerhard Lenski, Wilhelm Pöll, Fritz Straube and und wenn das nicht bald aufhört, the engineer Knothe.40 dann wird die Bude leer. During the first months of 1955 Oprema-1 was thoroughly checked and faults, as, for example, Refrain: cold solder joints or missing wires, were eliminat- Doch muß man noch dazu sagen, ed. In May the first trial runs were carried out, and dass es hier auch schwere Fälle gibt, on Monday, 1 August 1955, the computing center und ein jeder wird sich fragen, of CZJ was founded and the productive operation wer wird hier zuerst verrückt ? of Oprema-1 began. At the beginning of 1956 Ja, man kann hier viel erleben, Oprema-2 was put into productive use, too.41 alle freun sich nur noch auf eins, Given these dates, we may estimate how long eine Prämie wird es geben, it took to create the Oprema, though we have to nur für manche des Vereins. keep in mind that the Oprema was two separate computers. The official figure given has always Refrain: been 7½ months, which corresponds to the time span between 17 May 1954, the day of minister ( Melodie: Bravo, bravo ) Rau’s approval of the Oprema project, and 30 December 1954, when the “completion” was [ The Oprema ‒ Ballad ! reported to minister Rau.42 But, as the LWD show, work began earlier, and machine-1 was first ready Through the halls of Oprema for use between May and August 1955. Machine-2 the shepherds move to their place in the morning was first ready for use at the beginning of 1956. and they graft on the panels The LWD begin at 5 April 1954 and for machine-1 as if it was about a precious treasure. we may assume mid-June 1955 as the date it was Even the gentlemen designers first ready for use. Unfortunately, I did not find are soon at their wits’ end any record stating when Oprema-1 executed suc- they rack their brains cessfully its first program, such as the famous log if necessary even back at home. entry of 6 May 1949 for EDSAC: “Machine in operation for first time.”43 For Oprema-1 we thus 1 Refrain: obtain 14 /3 months (5 April 1954 to 15 June Tralla, tralla 1955) as a rough estimate of the time for design Super, super, almost like Oprema, and construction, which is still a remarkably short that is being built in Jena period compared to, e.g. the ASCC/Mark I (47 trallalala. months) or the ENIAC (30½ months). An even shorter time is reported for Colossus-1: “the Dollis Oprema is a class of its own, Hill engineers, having decided to make an all- that is known by everyone, electronic processor, took only 11 months to get and if that does not stop rather soon the first machine into service”.44 As we have seen the hut will empty out. above in the discussion of the time needed for Oprema-1, there is no clear-cut method to deter- Refrain: mine such time periods. The 47 months needed for But there must also be said ASCC/Mark I represent the time between the that there are serious cases here, too, approval of the project by IBM president Thomas and everyone will ask themselves J. Watson in February 1939 and the first successful who will be going crazy first ? execution of a test program in Jan 1943.45 With Yes, one may witness here a lot, regard to ENIAC Brian Randell says that the all are looking forward to one thing, memo of John W. Mauchly of August 1942 was there will be a bonus the “real starting point of the ENIAC project”, only for some of the club. however, he also states that “In fact, the ENIAC project was started only in May 1943, …” and Refrain: Brainerd says: “Although it was dated August ( Tune: Bravo, bravo ) ] 1942, no document bearing that date was ever found“. Arthur W. and Alice R. Burks report that The line “who will be going crazy first ?” sounds “Work started on May 31, 1943” and Brainerd like an echo of Brainerd’s remark in 1946: ”mental says: “work began officially in the Moore School breakdowns lurking around each weekend”. on June 1, 1943”. According to the Burkses “The
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 7 ENIAC solved its first problem in December of ten different developments which prepared the 1945”. This problem consisted of calculations for Moore School to undertake the first large-scale the development of the hydrogen bomb at Los electronic digital general-purpose computer;“. He Alamos. The first “working days” of ENIAC are mentions e.g. earlier work of Chedaker, Eckert, described in more detail by Haigh, Priestley & and Sharpless “on advanced electronic circuits, Rope.46 Colossus is usually not seen as a universal electronic counters, and delay lines on project computer but rather as a special electronic compu- PL;“ and “Burks and John Mauchly were invol- ting device or as the “Godfather of the Computer” ved in related radar work on project PZ (a Signal (Brian Randell), but there are also voices which Corps project obtained by Brainerd);“. Thomas P. claim that Colossus-1 was the first large-scale Hughes reports that Mauchly “had with him a electronic digital computer. On the other hand, a small breadboard model of a computer using neon trial to let Colossus perform base-10 multiplication tubes”, when he visited and then joined the Moore was not successful. More details about the compu- School in 1941. In the light of the detailed analysis tational capabilities of Colossus are given by of the Burkses it is questionable whether this is an Haigh & Priestley in their paper on “Colossus and adequate description of the artifacts Mauchly had Programmability”. The Burkses gave their book on built at Ursinus College, and these artifacts are Atanasoff the title “The First Electronic Comput- also not mentioned by Brainerd in 1976.50 er”, but they also clearly state that Atanasoff’s Thomas H. Flowers, who headed the develop- device was a “special-purpose digital machine” ment and construction of the Colossi at Dollis Hill, and that ENIAC was “ the world’s first general- says of himself: “By 1939 I felt able to prove what purpose electronic computer” and in 2018 ENIAC up to then I could only suspect: that an electronic is called “one of the earliest electronic general equivalent could be made of any electromechani- purpose computers ever made.”47 cal switching or data-processing machine.”51 Especially the beginning of these unique pro- Furthermore, these computers differed consid- jects cannot always be determined in a clear-cut erably in scale. ENIAC contained 18,800 vacuum way. There may be several specific possible dates, tubes, Colossus-1 contained 1,500 tubes and as e.g. 5 April 1954 vs. 17 May 1954 for the Oprema-1 contained 8,313 relays.52 Oprema, or August 1942 vs 1 June 1943 for ENI- Last but not least, the circumstances under AC. The memo of Howard H. Aiken, which led to which these projects took place may have influ- the ASCC/Mark I, was apparently written in No- enced the time for their realization. The Colossi vember 1937, more than one year before the ap- were built in a country which was directly attacked proval by IBM’s president.48 Furthermore, prelim- by an enemy: “DH had its share of air-raid warn- inary work by and the at that point current ings. On one occasion DH was narrowly missed by knowledge of the people, which created these a V2 rocket.” DH stands for Dollis Hill, the British computers, may have had an influence on the time Post Office Research Station in London, were the needed for development and construction. It has Colossi were developed and built. Such circum- been pointed out above that Kämmerer obviously stances implied enormous pressure on the people had done significant design work before 5 April building Colossus-1. Harry Fensom, one of them, 1954, and during his presentation Kortum said to recalls: “It took us many months to build Colossus, minister Rau that the delivery of the necessary working continuously, day and night. We even had relays had already been secured. a resident hairdresser to save valuable time!”.53 It cannot be determined what specific K&K and the Oprema team were under pressure knowledge about computers Kämmerer had, but due to the promise Kortum had given to Rau, who we may assume that he had at least read the book- was a minister in a dictatorial state. The main let of Heinz Rutishauser et al., which is mentioned reason for the ENIAC project was the necessity to in LWD on 24 April 1954: “Heft über „Pro- compute firing tables for newly developed military grammgesteuerte digitale Regengeräte“ erhalten weapons. The Moore School had recruited over [Have obtained booklet on „Program-controlled 100 women with college degrees who computed digital computing devices“; instead of „Re- such tables by means of paper and pencil and desk gengeräte“ it should read „Rechengeräte“ because calculators, “yet, they continued to fall behind the „Regengeräte“ = „rain devices“ obviously makes work load”.54 Only the ASCC/Mark I project no sense]“. This publication by Rutishauser, Am- seems to have not been under such specific kinds bros Speiser and Eduard Stiefel, who had visited of pressure. Aiken had been called to active duty the centers of computer development in the USA in April 1941 and then worked as an instructor at and the UK and also had close relations with Zuse, the Naval Mine Warfare School in Yorktown, Va. was praised by Franz L. Alt in 1952: “It is the first At IBM “The war slowed progress on the Harvard publication of its kind in German and far better machine, …” and “During World War II ─ while than most similar writings in English. . . ., it is IBM factories were producing carbines, automatic highly recommendable as an introduction to the rifles, cannon, bomb sights, gun directors, and fire subject.” It contains a bibliography of about 70 control mechanisms, as well as punched-card items, six of which were not publicly available.49 machines of prewar design ─ IBM engineers Brainerd said in 1976: “When one looks into undertook about a hundred special development the background of the ENIAC, one finds at least projects for the armed forces.”55
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 8 P P P Y Y P Y Program Number Plugboards Plugboards P Y
P C
Figure 4. One of the Oprema Machines. Control Desk Source: ZEISS Archiv. Figure 3. Floor Plan of One Oprema Machine (drawn by the author). ating instruction.56 This is far less material than the “hundreds of pages” mentioned by Alt for the Bell Relay Computer Model V, or the material con- Technical Properties of the Oprema tained in the patent application Z391 of Zuse or Available Material that in the ENIAC patent. Thomas Haigh, Mark Priestley and Crispin Rope say that they “combed The Oprema was dismantled in the autumn of through mountains of archival materials” when 1963 and the components were discarded or given preparing their book “ ENIAC in Action”.57 away to people interested in them. It seems that
the technical documentation suffered a similar The Oprema was a relay computer were elec- fate. Apart from the work reports by Lenski there tromechanical relays were used for essentially all only exist some technical notes about general switching and for dynamic storage. One machine principles, the pulse generator and the arithmetic contained 8,313 relays, approx. 45,000 selenium instructions, a paper by K&K, three papers by rectifiers, approx. 250 km wire, about 500,000 Kämmerer, 10 pages in the first edition of solder joints and an unknown number of resistors. Kämmerer’s book on “Ziffernrechenautomaten
[Digital Computing Automata]” and a short oper- Physical Structure Similar to the ENIAC one Oprema machine was a U-shaped assemblage of racks with the control desk inside the U. Fig. 4 shows one of the ma- chines, and Fig 3 is a floor plan (drawn by the author) indicating the different groups of plug- boards. The perimeter of one machine was 36.5 m. The panels on the inside contained the plugboards and some relays, and on the panels on the outer side the bulk of the relays was mounted in groups of 100 each. As can be seen in Fig. 4 all relays had a dust cover, which avoided malfunction due to dust and dirt. No incident with a moth similar to the famous “first bug”, which Grace Hopper found in the Mark II relay computer on 9 Sep. 1945, was reported for the Oprema.58 On the left arm there were 6 program plugboards (P) and on the right arm 5 plugboards for input numbers (Y and C). The role of these number plugboards will be de- Figure 5. People working inside Oprema on 15 Dec. 1954. tailed below. Source: ZEISS Archiv.
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 9 Program Control Control Unit Desk
Cyclic Memory 4 Typewriter
Arithmetic Unit
Constants 28 32 Registers
Figure 6. Block Diagram of the Oprema. (drawn by the author) Figure 7. A relais of the Oprema. Photo: J. Winkler.
plugboards, which were a kind of read-only memory. There were six plugboards for the pro- gram (P), each consisting of 50 rows, where one row contained one instruction. This means, that a program could consist of 300 instructions at most, which were numbered 0‒299. Input data was contained in the plugboards for constants (C) and in the so-called cyclic memory (Y). The plugboard for constants consisted of 28 rows, where each row could store one number à 39 bits. The cyclic memory consisted of eight plugboards of 40 rows Figure 8. Relay states and direction of current. each, where each row consisted of 41 sockets, 39 Part of Fig. 1 in Kämmerer’s “The Relay Technology for the 39 bits of a number and 2 sockets for the ...“. realization of shorter cycles. One cyclic memory consisted of two of these plugboards and therefore had a capacity of 80 numbers. The 32 internal registers consisted of relays and could store one number à 39 bits each. These registers were the only read-write memory of the Oprema. It is interesting to determine the storage capacity of one Oprema machine: program: 300 27 = 8,100 bits cyclic memory: 320 41 = 13,120 bits constants: 28 39 = 1,092 bits registers: 32 39 = 1,248 bits 23,560 bits Given these data, one Oprema machine had a Figure 9. The 3−Phase Pulse System of the Oprema. Fig. 2 of storage capacity of approx. 3 kByte, excluding the Kämmerer’s “The Relay Technology ...“. temporary registers of the control unit and the arithmetic unit.
The wiring was in the interior of this U-shaped The Relays structure. Figure 5 shows two people working on the wiring in the interior room of one machine.59 The relays were bistable polarized relays (latching The corridor inside the machine was 1.1 m wide relays) with up to three coils, each of which con- and 2.4 m high. The framework of the Oprema sisted of 5400 turns and had a resistance of 1200 consisted of steel and the panels of lacquered high- Ω. Fig. 7 shows a relay which has come into the density fiberboard. Lenski reports on 22 May author’s possession. Depending on the direction of 1954: “Anstatt Duralblech kann Holzfaserhartpap- the current through a coil the relay either assumes pe genommen werden wenn es geht etwas stärker the state AZ or AT (see Fig. 8). If the current is als 4 mm. [Instead of duralumin sheet we may use turned off the relay remains in its present state. high-density fiberboard if possible a bit thicker The relays were operated by direct voltage of ± 6 than 4 mm.]” V, and a pulse of 5 ms duration was sufficient to put the relay in the corresponding state. In the Logical Structure/Block Diagram following, a relay will be called “activated” if its contact is in position AZ and “deactivated” if its The logical structure of the Oprema is depicted in contact is in position AT. Fig. 6. The memory almost entirely consisted of
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 10 Associated Coils Contacts Overall Control Circuits The machine was controlled by a system of pulses. The main circuits were controlled by a 3-pulse Z system (I, II, III), and the part that controlled the n electric typewriter was controlled by a 2-pulse A system. The 3-pulse system is depicted in Fig. 9. T 1 One pulse is 13 /3 ms long followed by a pause of 2 6 /3 ms, and the three pulse sequences are stag- gered symmetrically. The pulses are produced by Z n+1 cam-operated contactors in the pulse generator. A For the control of relay systems with different T pulse systems CZJ obtained a patent in the FRG (West Germany) but apparently not in the GDR (East Germany). The inventors named in the pa- Z tent were Kämmerer, Kortum and Pöll.60 n+2 A One design rule was that the coils of a relay T were all driven by the same pulse sequence, i.e. with respect to its coils, a relay belonged to one of the pulse sequences I, II or III. A second design Figure 10. Basic principle of the control se- quences. The activation wave has reached relay rule was that the contact of a relay whose coils n+1 (drawn by the author). were driven by pulse sequence I controlled the coils of relays of group II; the contact of a relay of 200 mA led to wear-out of the contacts after 25 to group II controlled the coils of relays of group III, 100 million switches, whereas the contacts were and the contact of a relay of group III controlled still in very good shape after one billion switches the coils of relays of group I. There were thus when switched in current-free mode.62 three groups of relays 1, 2, and 3 whose coils and Fig. 11 shows the overall logical structure of contacts were associated with the three pulse the Oprema, and especially the different control sequences as indicated in table 1. An example of sequences which controlled the sequencing of the these design rules is the so-called “Führungskette single steps of the computation. Whereas Zuse [guiding chain]”) which is detailed below. In the used stepping switches for this control, the Opre- following I will use the term “control sequence” ma used relays for this purpose, too. for Kämmerer’s German term “Führungskette”. Control Sequences Associated Pulses The control sequences are chains of relays which Relay group Coils Contacts could split into branches and also merge again. In 1 I II all paths the relays of the control sequences are 2 II III numbered according to their distance to relay 1. 3 III I The relays of a control sequence are activated one after the other, and, as a consequence, a wave of Table 1. Association between relay coils, relay relay activations is flowing through the network. contacts, and the three pulse sequences. As can be seen in Fig. 9, a new pulse starts every
62/ ms, which means that the activation wave is A consequence of these two design rules and the 3 flowing through the network with a frequency of structure of the 3-pulse system is that the relay 150 relays/s. When a relay is activated it may contacts are switched in a current-free state. This trigger some circuit of the computation proper. is an important factor for the reliability of the This basic principle is depicted in Fig. 10. The computer because it extends the lifetime of the activation wave has reached relay n+1 which contacts and also significantly increases their triggers its associated circuit. Relay n is deactivat- reliability. This had already been observed by ed again and relay n+2 is still deactivated, and Zuse around 1940. When a contact is opened while therefore they both do not trigger their associated a current is flowing through it and thus a circuit circuits. containing any coils is broken a spark is produced Due to the switching characteristics of the by the self-induction of the coils. Such sparks lead bistable relays and the control by the 3-pulse to an increased contact wear-out which is especial- system Kämmerer used a somewhat more compli- ly important for the relays in computer circuits cated scheme for the circuits of the control se- where the relays are switched much more often quences. In this scheme, when relay n is activated, than in telegraphy and telephone systems.This it problem had already been pointed out by Leonardo a) activates relay n+1, Torres y Quevedo in 1915.61 The Oprema people b) triggers its associated circuit and did several endurance tests for the switching of the c) deactivates relay n−2. relays with contacts made of a gold-nickel alloy. The results were that switching under a load of
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 11 Figure 11. The Control Sequences of the Oprema. Fig. 78 from Kämmerer’s “Ziffernrechenautomaten“.
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 12
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 13 This is depicted in Fig. 12, in which the circuits state of the Oprema, in which the activation wave associated to the relays of the control sequence are circulates in this control sequence. When the start- not shown. (Fig. 10 and Fig. 12 have been drawn button is pressed relay 1 is activated and the exe- by the author on the basis of Kämmerer’s descrip- cution of the next instruction begins. If, after tion in his 1958 paper on the relay techniques used completion of an instruction, the stop-button is not in the Oprema.) In Fig. 12 solid lines carry a posi- pressed control directly returns to relay 1. tive voltage and dashed lines are on ground level. When the machine should be switched off The different colors indicate the three different completely, the camshaft, which generates the pulse sequences: red for pulse sequence I, green pulses of the pulse systems, is stopped first and for II and blue for III. The positive voltage of the then the power voltage is switched off. pulses is fed into contact A of the relay. In this scheme the activation wave consists of three con- Number Representation and Arithmetic secutive relays which are activated (AZ closed), Numbers are represented as normalized floating- while the other relays of the control sequence are point numbers ± s10±e, where deactivated (AT closed). s = Dddddddd Fig. 12 shows six consecutive relays of a D is a decimal digit greater zero control sequence in four consecutive states. In d is a decimal digit order to understand these four states, we have to e is an integer with 0 ≤ e ≤ 15. take into account a further detail of the 3-pulse system which is not explicitly depicted in Fig. 9: The excess-3 code is used for the representation of when the pulses are switched on or off there are the digits of the significand, i.e. each digit is repre- very short time intervals during which only that sented by a 4-bit group, which Kämmerer called a pulse is on which does not change. E.g. if pulse I “Tetrade [tetrad]”. The exponent e is represented goes up and pulse II goes down only pulse III is directly as a binary number using another tetrad. on. This is depicted in Fig. 12 in state (a). Together with the two bits for the two signs one In state (a) relays 32, 33, and 34 are activated, number needed 38 bits for its representation, and, as already mentioned, only pulse III is up. which were numbered 1 to 38. Since zero cannot be represented as a normalized floating-point When pulse I goes up, relay 34, which is already th activated, activates relay 35, which switches from number there was an additional 39 bit which was AT to AZ. Additionally, relay 34 deactivates relay used in the following manner: for the normalized 32, which switches from AZ to AT. As a result, numbers bit 39 is off (“0”), and if bit 39 is on the relays 33, 34, and 35 are now on, and the other (“L”) the bits 36, 37, and 38 represent one of three relays are off. Thus, the group of three activated special values (“Sonderzeichen”): relays has moved one step ahead. 36 37 38 39 The transition from state (a) to state (b) shows zero 0 0 L L that the relay contacts are always switched in a infinite 0 L 0 L current-free mode: the contacts of both the relays indeterminate L 0 0 L 32 and 35 are connected to the pulse sequence II Kämmerer says that these special values are also which is down during this transition. used in subsequent computations, but the available When pulse III goes down the network enters documentation does not contain the algebraic rules state (c) in which the state of the relays is the same for these values. These rules should be the same as as in state (b), whereas contact A of relays 33 and those reported by Stiefel for Zuse’s Z4: 36 is on ground level. e.g. infinite ‒ infinite = indeterminate. When pulse II goes up the network enters state Zuse, who also used normalized floating-point (d), in which the relays 34, 35, and 36 are activat- numbers in his early computers, used the special ed, and the other relays are deactivated. Again, the values 0, ∞, and ? (indeterminate). Such special group of three activated relays has moved one step values are also present in modern floating-point ahead, i.e. each new pulse moves the group of formats as e.g. ± ∞ and NaNs in IEEE 754-2008. activated relays one step ahead. Thus, the floating-point formats of Zuse and Kämmerer were early forerunners of the modern Execution of Instructions floating-point standards.63 The execution of an instruction starts with the Plugboards were used for the input of num- activation of relay 1 in the middle of the upper part bers. These plugboards consisted of rows of 39 in Fig. 11. Depending on the instruction one of the sockets according to the 39 bits used for the repre- paths through the network is taken, and when the sentation of one floating-point number. There instruction is completed control returns via the existed special four-pin plugs (“Tetradenstecker”) relays 3n-1 and 3n at the bottom to the circuit for the different decimal digits of the significand. which decides whether the result of the instruction The sockets were interconnected in such a way should be printed. If the stop-button has been that no plug was necessary for the digit zero. The pressed control enters the control sequence in the numbers could also be plugged in in unnormalized middle of the upper part. This control sequence form and would afterwards be automatically nor- consists of six relays which are wired in a circular malized when read into internal registers. There fashion. This control sequence implements the idle
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 14 were two kinds of number plugboards whose role digits of the significand of the quotient are com- will be discussed in the section on programming. puted sequentially from left to right by comparing The arithmetic operations of the Oprema were the current rest r ‒ which is initially the signifi- addition, subtraction, multiplication, division and cand of the dividend ‒ with the multiples of the extracting the square root. Addition was performed significand of the divisor computed in phase 1. in a parallel manner because this was faster than The largest multiple si which is less or equal to serial addition. This compensated a little bit the r is the next digit of the quotient: disadvantage of using the rather slow relay tech- si ≤ r < s(i+1) (1) nology. The arithmetic operations were all based This is basically the same algorithm as that of the on addition, and therefore the two parallel adders usual pencil-and-paper method. This basic algo- were the central components of the arithmetic unit. rithm was improved in two points: (a) the compar- These two adders processed the significands of the ison to determine the largest multiple which is less operands. In the following it is assumed that the or equal to the rest was limited to the first two registers of the adders were 9 digits long, because digits d0d1 of both the rest and the multiples and this is necessary to add all significands correctly: (b) instead of the maximal i with e.g. (si)0−1 ≤ r0−1 5000 0000 + 6000 0000 = 1 1000 0000 the minimal i for which But the available documentation does not describe (si)0−1 ≥ r0−1 (2) such details of the adders. In the following exam- holds was computed. ples the significands will be in this 9-digit format: Condition (2) is simpler to implement but has d0 d1d2d3d4 d5d6d7d8 . the drawback that i is not in all cases the next For normalized significands digit qj of the quotient. If d0 = 0 d1 > 0 (si)0−1 > r0−1 holds. holds then Multiplication was performed in two phases. si > r In phase 1 the nine multiples s1, s2, …, s9 of does also hold and qj = i−1 is then the next digit the significand s of the multiplier are computed of the quotient. But even if by repeated addition and stored into the nine regis- (si)0−1 = r0−1 ters of the “Vielfachenspeicher” (storage of multi- holds ples). In phase 2 the significand of the product is si > r computed by repeated addition of the multiples of may also hold if the significand of the multiplier according to the (si)2−8 > r2−8 digits of the significand of the multiplicand. This is true. sequence of additions starts with the rightmost This can be seen in the following example: digit d8 of the significand of the multiplicand. let s = 0 2010 0000, r = 0 8000 0000, i = 4. After each addition the partial product is shifted to With this we have: si = 0 8040 0000 and the right by one place. Thus, the nine most signifi- cant digits of the significand of the product are (si)0−1 = r0−1 08 = 08 computed. Parallel to this computation the two but also exponents are added together in the separate expo- (si)2−8 > r2−8 040 0000 > 000 0000 nent adder and the sign of the result is determined and therefore by the signs of the two significands. Finally, the si > r 0 8040 0000 > 0 8000 0000 . resulting sign, significand and exponent form the In this case i−1 is the correct value of the next result, which is, in a last step, normalized into the digit of the quotient. form described above. This description of the Therefore, after i is determined according to multiplication follows that in the anonymous and (2) the two subtractions undated note “Der Multiplikationsablauf“ (cf. ma := r − si; and sa := r − s(i−1); endnote 56). In Kämmerer’s “Ziffernrechenauto- are performed in parallel in the main adder (ma) maten“ of 1960 the roles of multiplicand and and in the secondary adder (sa), respectively. The multiplier are interchanged (p. 126), but since new rest and the next figure qj of the quotient are multiplication is commutative both descriptions then determined as follows: are logically equivalent. Both descriptions are if ma ≥ 0 incomplete in that they do no describe how the then r := ma; q := i; mechanism works for the digit 0 of the signifi- j else r := sa; q := i−1; cand of the multiplicand resp. multiplier. Richard j K. Richards calls this form of multiplication “N- fi tupling“.64 Similarly as in multiplication, the difference of the The division operation consisted also of two exponent of the dividend and the exponent of the phases. Phase 1 was similar to the first phase of divisor is computed in the exponent adder and the multiplication: the nine multiples s1, s2, …, s9 resulting sign of the quotient is determined by the of the significand s of the divisor are computed signs of the two significands. In a last step the by repeated addition and stored into the nine regis- resulting sign, the significand of the quotient, ters of the storage of multiples. In phase 2 the which may be denormalized, and the resulting
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 15 exponent form the result, which is normalized into but it seems that he was not aware of the Opre- the Oprema floating-point format. ma.66 Again, this presentation follows the descrip- tion of the division operation in the anonymous Rounding and undated note “Der Divisionsablauf“ (cf. end- Due to the fixed length of the significand in the note 56), but is a little bit more detailed than that. Oprema floating-point format the significand of In his “Ziffernrechenautomaten“ of 1960 the result of an arithmetic operation had to be Kämmerer gives a slightly more intricate descrip- rounded to fit the Oprema format described above. tion especially of the to the first two digits limited The Oprema used two forms of rounding, one in comparison of the current rest and the multiples of the main adder and a second in the normalization the significand of the divisor. Both descriptions group. In the main adder rounding is necessary are incomplete in that (a): r must be multiplied by after right shifts, when e.g. during addition the 10 after qj has been computed and (b): the regis- significand with the smaller exponent must first be ters in the adders and the storage of multiples shifted right n places, where n is the difference should be 9 digits long. between the larger and the smaller exponent of the It is interesting to note that Charles Babbage, two summands. Right shifts also occur during who used fixed-point numbers, envisaged a very multiplication, as already mentioned above. In similar algorithm for division for his Analytical these cases the rounding method is roundTie- Engine. He also limited the comparison of the rest sToAway aka banker’s rule which was the stand- r and the multiples of the divisor d to the first ard rounding in numerics at the time of the Opre- two digits of both, respectively. As the candidate ma.67 for the next digit of the quotient he chose the In the normalization group a simpler rounding largest multiple di which is less or equal to r. method was employed (roundNorm), which seems With this we obtain the kernel of Babbage’s algo- to be rather unique. The method takes the last two rithm: digits d8d9 of the unrounded significand i := max(k: (dk) ≤ r ); 0−1 0−1 su = d0d1d2d3d4d5d6d7d8 r := r − di; qj := i; into account according to the following rule: if r < 0 d8 = 0 # sr = 0d0d1d2d3d4d5d6d7 then r := r + d; qj := qj − 1; fi d8 ≠ 0 d7 is odd # sr = 0d0d1d2d3d4d5d6d7 It seems improbable that Kämmerer knew of d8 ≠ 0 d7 is even # sr = 0d0d1 … d6(d7+1) Babbage’s algorithm, and thus, this may be an where sr is the rounded significand. example for the conclusion which Maurice Wilkes Examples: draws at the end of his paper “Babbage as a Com- roundNorm(1 2222 2219) = 0 1222 2221 puter Pioneer”: “As it is, everything that he dis- roundNorm(1 2222 2221) = 0 1222 2223 covered had to be re-discovered later.”65 The most complicated arithmetic operation of The reason for this special rule was that d7+1 the Oprema was the extraction of the square root. will never produce an overflow because d7 = 8 is It is described in the short, anonymous and undat- the largest possible even value. In roundTie- ed note “Das Wurzelziehen“ (cf. endnote 56) and sToAway rounding is usually done by adding 5 in more detail in Kämmerer’s “Ziffernrechenau- to d8 which may result in an overflow into d7 tomaten“ of 1960 (pp. 110−111, 128−129). If the and this overflow may ripple to the left until d0 as radicand is negative the result is the special value in “indeterminate”. For positive radicands the opera- su = 0 9999 9995 , tion is based on the well-known relation which means that for roundTiesToAway a full n2 = 1 + 3 + … + 2n–1 adder is necessary. RoundNorm can be imple- mented by a much simpler circuitry and this is i.e. n2 is the sum of the first n odd integers. mentioned as the reason in the anonymous and A basic algorithm implementing this relation undated note “Abrundung bei der Normierung works by successively subtracting consecutive odd [Rounding during normalization]” (cf. endnote integers from the radicand resp. rest beginning 56). In Kämmerer’s “Ziffernrechenautomaten” of with 1. If the radicand is somewhat larger this 1960 the description of this rounding method basic algorithm leads to a sizable number of sub- contains a contradiction and therefore seems to be tractions. The computation of e.g. ÷1225 = 35 68 incorrect. involves 35 subtractions and 35 additions to com- The simpler circuitry also has some disad- pute the sequence of odd integers. In the Oprema vantage: the mean absolute rounding error is about the basic algorithm is improved by applying these twice that of roundTiesToAway, which is the same subtractions to groups of two decimal places as it as that of the modern roundTiesToEven. On the is done in the well-known paper-and-pencil “divi- other hand, the mean rounding error is zero, i.e. sion“ method. With this improvement the compu- when summed up over the 100 possibilities of d d tation of 1225 is completed in 11 steps. This 7 8 ÷ the rounding errors are cancelled out and, there- improved method is also described by Richards, fore, roundNorm shows no drift in the sense of John F. Reiser and Donald E. Knuth.69 With re-
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 16 Y0 Register
Y1 Register
Arithmetic Unit
Y2 Register
Y3 Register
Figure 14. The four cyclic memories (drawn by the author). Figure 13. “Loading“ of a program at the plugboard. Source: de Beauclair “Rechnen ...“, p. 103 Adr1 and Adr2 are 6 bit wide. The result can be (https://archive.org/details/rechnenmitmaschidebe). written to one of the 32 internal registers, and therefore, 5 bits are sufficient for Adr3. Adr4 spect to the ambivalent case d8 = 5 roundNorm consists of 2 2 bits and determines the next behaves as roundTiesToOdd. RoundTiesToEven instruction to be executed. If these 4 sockets are (RTTE), which was recommended by James B. empty the next instruction in the program plug- Scarborough in 1930 and which is attributed to board is executed, where instruction 299 is fol- Carl Friedrich Gauss by Burks, Goldstine and von 70 lowed by instruction 0. The first two sockets of Neumann in 1946 , can lead to the rippling over- Adr4 are used for conditional jumps and the last flow mentioned above: two sockets are used for unconditional jumps. RTTE(1 9999 9995) = 0 2000 0000 As already mentioned above, the Oprema also had Adr4C Adr4U a secondary adder, but the remaining documenta- ○ ○ ○ ○ tion contains no information about the rounding method used there. Since the secondary adder cond. uncond. jump essentially had to perform additions of the same kind as the main adder it may be assumed that roundTiesToAway was also used in the secondary For an unconditional jump from instruction i1 to adder. Kämmerer remarks that the primary adder the instruction i2 the left socket of instruction i1 and the secondary adder had the same structure.71 and the right socket of instruction i2‒1 are con- nected to each other by a jumper cable: Instruction Set The Oprema was a four address machine with the i1 ○ ○ ● ○ following instruction format:
i2‒1 ○ ○ ○ ● Adr1 Op Adr2 Adr3 Adr4 i2 ○ ○ ○ ○ 6 6 6 5 4 bits
One instruction consists of 27 bits. Adr1 and Adr2 This holds for forward jumps as well as for back- refer to the input data of the instruction and Adr3 ward jumps within one program table. For the refers to the place where the result is stored, where realization of jumps between different program the following condition must hold: tables there exist special connections between the Adr3 ≠ Adr1 Adr3 ≠ Adr2 . tables (“Fernverkehrsstraßen” [“long-distance The input can come from the constant plugboards highways”]). The destination of a conditional jump (28 numbers), from one of the 4 cyclic memories is determined in an analogous manner using the or from one of the 32 internal registers. Together, first two sockets of Adr4. Figure 13 shows the 72 this are 64 different possibilities, and therefore, “loading” of a program at the plugboard. Jumper
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 17 and therefore 0 . . . 39 40 Adr3 := + |(Adr1)| + − |(Adr2)|; print( (Adr3) ); goto 253; 0 ○ ○ . . . ○ ○ 1 could be expressed in one instruction. A very 73 . similar scheme was used in the ASCC/Mark I. . The remaining 9 operations were: . Cyclic Adr3 := (Adr1) (Adr2);
Arithmetic Adr3 := (Adr1) / (Adr2); Register Memory Unit Adr3 := + ÷(Adr2); Adr3 := − ÷(Adr2); if (Adr1) > 0 then goto Adr4C; if (Adr1) = 0 then goto Adr4C; 79 if (Adr1) = • then goto Adr4C; Adr3 := (Adr1); Figure 15. A cyclic memory with two jumps (drawn by the end of computation (loop stop). author). The Oprema was, as this instruction list shows, well suited for all kinds of numerical computations within the limits of its restricted storage capacity. The only feature which was specific for optical calculations was the so-called cyclic memory, whose logical structure is depicted in Fig. 14. As already mentioned, this consisted of four groups of two plugboards, where each of these plugboards Fig. 16. Ideal 1:1 Projection by a Symmetrical Lens System. contained 40 rows à 41 sockets, the first 39 sock- Courtesy of Eberhard Dietzsch. ets for the 39 bits of a floating point number and the last two sockets for the realization of jumps analogous to the unconditional jumps in the in- struction tables. Access to the cyclic memories is provided by four registers which contain one of the numbers of the corresponding cyclic memory. The settings at the control desk determine which numbers are in these registers when the program execution is started. After each read access to one of the registers the next number of the correspond- ing cyclic memory is transferred into this register. This access is done in a cyclic manner. Additional- ly, it is possible to alter this basic cyclic order by “unconditional jumps” using the sockets 39 and 40 in the same way as the sockets 25 and 26 are used in the program tables (see Fig. 15). The mechanism of the cyclic memories can be seen as a simple form of index registers. It was Fig. 17. The Retrofocus Wide-Angle Lens Flektogon 4/50 with motivated by the calculations for the design of Selected Ray Paths for an Infinite Object Distance. compound lenses, as e.g. camera lenses. Courtesy of Eberhard Dietzsch. A camera lens should map the object, ideally, as an exact, i.e. geometrically similar, image onto the film or, nowadays, onto the image sensor. In cables are seen in the two narrow columns at the order to do this it is necessary that all different right end of each program table. light rays travelling from one point of the object The operation field is 6 bit wide, which allows plane through the several lenses of the lens system for 64 different operations. The first five bits meet again at one corresponding point of the im- determine the operation proper and bit 6 controls age plane. Fig. 16 shows the theoretical principle the printing of the result of the current instruction. and Fig. 17 is a real design drawing by Eberhard The remaining five bits allow for 32 operations, 25 Dietzsch, a former lens designer at CZJ. It is based on data of the design of the f = 50 mm Flektogon of which were actually used. 74 There were 16 different kinds of addition, f/4 in 1958. Fig. 17 is a computer generated which varied in the treatment of the two operands diagram. Back in the 1950ies such diagrams were (Adr1) and (Adr2) where, as usual, “(Adr)” means drawn by hand. the number contained in the memory cell with In reality, the ideal mapping can only be ap- address “Adr”. Each of the two operands could proximated, because, e.g. the refractive index of come in four forms: glass varies with the wavelength/color (chromatic aberration). If we want a picture which is sharp for + (Adr), ‒ (Adr), + |(Adr)|, ‒ |(Adr)| ,
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 18 objects in different planes things are even more and the distances were stored analogously: complicate and rather impossible by purely optical Y2[0] Y2[1] Y2[2] . . . means. One current approach to overcome these d d d . . . 75 0 1 2 limitations is focus stacking. At the time of the These sequences were realized as circular se- Oprema, geometrical ray tracing was often used in quences by means of the “jump” mechanism de- lens design. This means, that the paths through the scribed above. lens system of e.g. 100 different rays are computed The characteristic values (cv) of the different using the laws of geometrical optics. For each ray rays, e.g. starting point and initial direction, were the refraction at the surfaces between two optical stored in the last cyclic memory: media, e.g. glass and air, or two different sorts of glass, has to be computed sequentially from object Y3[0] . . . Y3[k] . . . Y3[2k] . . . to image. The refraction at one spherical surface cv0 cv1 cv2 . . . were each cv consisted of k numbers. depends on the refractive indices n1,2 of the two media, the radius r of the surface and of the angle The number of rays and the number of surfac-
Oprema 1st computer 2nd computer a) Time for prepara- Programming 10 tion “Loading“ of 100 100 min. the program 20 b) Time for calcula- 31 1100 790 tions Contains 80 min. for Contains 30 min. for the recalculation of 15 the recalculation of 15 erroneous results erroneous results found by the comput- found by the comput- er himself. er himself. c) Number of errors 0 19 9 found only in the on average almost 10 % unnoticed errors final comparison d) Addition for de- 0 266 90 bugging (200% per error) e) Time for preparing ‒ 90 90 and checking a typewritten tran- script of the results f) Factor of times for 1 41 28 calculations and debugging (b+d)
Table 2. The results of Kämmerer’s experiment. es were stored in the constant table, and thus, the machine was in a suitable state to begin the ray of incidence i. Furthermore, the distance d be- tracing calculations.76 tween two successive surfaces has to be taken into account. When all the paths of all rays have been Reliability computed, it is checked whether the quality of the One of the reasons K&K gave for the use of relays image is sufficient. In the beginning of the design instead of vacuum tubes, which had then typically of a lens system this is often not the case. Then been used in computers for several years already, one or more of the parameters are changed by a was that relays were more reliable than tubes.77 small amount and the computation is repeated. But even the early electromechanical computers This approximative process is continued until an also had serious reliability problems: acceptable design is obtained which is then used ”Computations were checked frequently: as often for production. as every twenty minutes to ensure that the machine Kämmerer describes the use of the cyclic was not spewing out volumes of nonsense. Besides memories for these calculations in one example. using that check, problems were often recorded The refractive indices were stored in the order and run again using the same direct evaluation from object to image in one of the cyclic memo- method, but using different parts of the machine. ries, e.g. Y0: In all, the checking of the machine for errors was Y0[0] Y0[1] Y0[2] . . . an important, time consuming part of the work of n0 n1 n2 . . . the Havard Computation Laboratory.“78 the radii were stored in a second cyclic memory: As has already been mentioned above, experi- Y1[0] Y1[1] Y1[2] . . . ments had shown that the contacts of the relays r0 r1 r2 . . . were still in very good shape after one billion
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 19 switches when switched in current-free mode. But Since both machines worked very reliably nevertheless, the relays turned out to be the main after the debugging was completed, the cables to source of problems during the debugging of the connect the two machines and make the checking two machines in 1955. On one occasion almost all modus possible were never installed, and the relays of Oprema-2 and the 2,000 relays in reserve Oprema was thus always used as two separate had to be partially disassembled, readjusted and computers.82 then reassembled, because a rivet of the armature In his report “5 Jahre “Oprema” [5 Years had to be retightened. “Oprema”]” Alfred Jung gives the productive Furthermore, Kämmerer did an experiment in hours for both machines together for the years 1955 during the trial period (May to July 1955) to 1956 ‒ 1960: assess the reliability of Oprema-1. It consisted of 1956 8,589 64 % th the computation of a polynome of 5 degree for 1957 9,445 70 % 151 argument values. These calculations were 1958 10,512 78 % done by Oprema-1 on the one side and by two 1959 11,530 85 % experienced (human) computers, working inde- 1960.Jan-Jun 5,948 88 % pendently, on the other side. The human comput- The basis for these statistics are ca. 13,520 possi- ers worked with paper, pencil and 8-digit Mer- ble productive hours per year for both machines cedes Euclid desk calculators. The results of this together: each week from Monday 06:00 to Satur- experiment are given in a table of Kämmerer day 16:00.83 (Table 2). In this table “computer” means a human computer, which was still a common term at that Operation and Use time.79 The essential result was that the Oprema was faster and better than the human computers. On 1 August 1955 the “Rechenraum Oprema The Oprema always computed the correct result. [Computing Room Oprema]” was founded as a Kämmerer was especially astonished that the separate unit, and Oprema-1 was put into produc- individual results of the human computers con- tive use. Alfred Jung, a mathematician who had tained about 10% erroneous values despite the fact worked on the logic design of the Oprema, was the that the form of the polynome facilitated the first supervisor of the Rechenraum. As for the date checking of the values. Unfortunately, his report of the start of the project, different dates for the does not contain the formula of the polynome so beginning of the productive use of Oprema-1 are that we cannot judge this aspect of the experiment mentioned by different authors. Kortum mentions ourselves.80 1 May 1955, Fritz Straube, a deputy of Kortum, The original design of the Oprema envisaged a mentions the beginning of June 1955, whereas system of two identical machines which could Jung says in the report “5 Years “Oprema” ” that work in two different modi: as two independent the productive use started at 1 August, and Kämmerer says “von August an [from the begin- computers and as a combined system. In the com- 84 bined modus the two machines would execute the ning of August]”. same program with the same input data. After the It seems that, despite the fact that the Oprema completion of an instruction the two results would was retired in autumn 1963, the first five years be compared. If they were different, the machines were the most productive time of the Oprema, would enter the idle state mentioned above and a because two machines of the type ZRA 1 (Zeiss- red and a green lamp at the console would be Rechenautomat 1 [Zeiss Computing Automaton turned on. In this situation there would be several 1]) were installed in the Zeiss computing center in possibilities for continuation: spring 1960, which boosted the capacity of the computing center by a factor of 40. The ZRA 1 ‒ repeat the last instruction; this could be success- was the second computer model developed and ful in case of a transient failure; built by CZJ; about 33 ZRA 1 were produced. The ‒ insert the correct result values and continue the “Computing Room Oprema” had been renamed program; “Computing Center” in 1959.85 ‒ execute some test programs in order to try to It seems that after the Rechenraum Oprema locate the fault, do the repair, and then continue had been founded there was still some debugging the program; necessary. Kämmerer reports for Oprema-1 10 ‒ switch the machines off. productive weeks from August to December 1955. The twin-machine approach to improve the overall During these weeks the machine was operated reliability of a computing system was also used in 13286 hours per week: three shifts from Monday to the Harvard Mark II and the BINAC. Both are Friday and two shifts on Saturday. During these 10 mentioned in the booklet of Rutishauser et al., but weeks 18 orders for optical systems had been no details are given there, and it is not known completed in 1040 productive computing hours in whether Kämmerer knew the more detailed publi- total. In a separate table Kämmerer lists 21 orders cations which had been published at that time. The with a total of 978 hours, which were billed to the Mark II was even more versatile than the Oprema: customers with 115 DM per hour.87 15 of these additionally to the two modi described above, the orders came from WOPho, the computing bureau Mark II could also work as one combined machine for photographic lenses, whose head was Harry 81 on problems too large for a single machine. Zöllner, who had also advocated the development
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 20 of the Oprema. For WOPho the use of the Oprema Z5 Oprema was a great success. A table dated 1 January 1958 Addition 100 ms 120 ms shows that the number of successive design sam- Multiplication 400 ms 800 ms ples during the development of one design ready Division 750 ms 800 ms for production dropped sharply after the Oprema Square root 750 ms 1200 ms 88 had been used: A second reason for the use of relays seems to be Year 1954 1955 1956 1957 that K&K and CZJ as a whole were not familiar a) # of design with electronics but rather with mechanical and samples 29 17 23 18 electro-mechanical methods. The devices devel- b) # of designs oped by Kortum and his group in the 1930s and ready for 1940s consisted of mechanical, electro-mechanical production 2 7 16 15 and optical components. In their 1955 paper on the Percentage of b) 7 41 70 83 Oprema K&K mention that a computer for optical calculations based on analog elements had been Two reasons for these improvements were that designed at CZJ before. This machine would have more rays could be included in the calculation and had a number range too small for the intended that it was also possible to include aspheric surfac- applications, and they therefore decided to build a es.89 digital computer. Furthermore, the tight schedule There also were a number of external custom- based on Kortum’s promise to minister Rau left no ers, because during those years the Oprema was time to study and learn the new technology of the sole program-controlled computer in the GDR. digital electronics. Kortum still wrote in 1959: Therefore, the percentage of productive time used “Die bei uns vorhandenen Röhren sind solchen for orders from CZJ dropped steadily Anforderungen noch nicht genügend gewachsen, 1956 95 % CZJ … [The vacuum tubes availabe for us do not yet 1957 90 % CZJ meet such requirements, …]”. Only in the 1960s 1958 77 % CZJ was electronics introduced at Zeiss. The first 1959 75 % CZJ internal conference on electronics took place in Among the external customers were: 1964, and when the last general director, Wolf- University of Rostock gang Biermann, came to CZJ in October 1975, he VEB Turbines and Generators, Berlin observed that CZJ had begun to incorporate elec- WTB Nuclear Reactor Construction, Berlin tronics into their products too late.94 German Federal Railway The situation of K&K with respect to electron- German Metereological Service, Potsdam ics was very similar to that of Aiken and his co- Observatory Babelsberg workers in 1944 and 1945 when the Mark II pro- Geodetic Service, Leipzig ject was started. The Navy “urged that the machine 90 University of Halle. be so designed that its construction could be com- pleted as soon as possible. Accordingly, it was Why relays in 1954? decided to build a relay calculator.” Additionally, Despite the fact that Kämmerer was well aware Robert Campbell, who was involved in the design that vacuum tubes were already used in computers of the Mark II relay computer, later wrote in retro- and that transistors were the switching components spect: “It may be noted that we had no one on of the future, K&K decided to use comparatively board with experience in the technology of televi- slow relays as the switching elements of the sion or of radar: these fields were to provide the Oprema. One reason was that relays were more principal expertise in high-speed pulse circuitry.” reliable than vacuum tubes, a fact which is also Eckert, one of the designers of ENIAC, is even mentioned by George R. Stibitz, who was heavily more explicit in a letter to Robert P. Multhauf of involved in the development of the relay calcula- the Smithonian Institution dated 22 July 1963: “I tors and computers at Bell Labs during the 1940s: was chief engineer and thus in charge of the ENI- “And so, with Model VI an era was ended. By AC project. My experience with analog computers 1950 the excitement of electronic potentialities was no great help in building the digital ENIAC, ... was sweeping the country, and our blessedly relia- The influence of the radar switching and timing ble old relays were slow by comparison.”91 circuitry was more important and significant than With a multiplication time of 800 ms the the analog computer.“ Flowers, who headed the Oprema was about as fast as other parallel relay development and construction of the Colossi has computers, as e.g. the Bell Relay Calculator Model already been cited above: “By 1939 I felt able to V (1 s) and Aiken’s Mark II Calculator (800 ms). prove what up to then I could only suspect: that an But the relay computers were significantly slower electronic equivalent could be made of any elec- than their electronic counterparts, as e.g. ENIAC tromechanical switching or data-processing ma- (5.6 ms). Konrad Zuse, who never saw the Opre- chine.” ma, supposed that it “was probably the fastest On the other hand, both Heinz Billing and relay computer ever built.”92 But a closer look Maurice V. Wilkes (EDSAC) had experience in reveals that his own Z5 (completed in 1953) was electronics when they began to develop electronic slightly faster than the Oprema93: computers, and, had, by no means, such pressures
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 21 as the Colossus, Mark II, ENIAC and Oprema tion]“. The ONR report mentions the “ALWEG people.95 Corp., Cologne, Germany” as one of the installa- tion sites and so does the BRL report of 1955.100 Overall evaluation It seems that Kämmerer made the best of the Despite the fact that technologically it was a late- relay technology he and Kortum had chosen as the comer, Oprema was the 7th computer in Germany basic technology. They used bi-stable self-latching and the first computer in the GDR. relays which were switched between two stable The first computers in Germany were: states by short pulses, and therefore did not need a Z3 Zuse 1941.May permanent current to hold them in one or the other Z4 Zuse 1945.March state. This reduced the power consumption signifi- G 1 Billing 1952.Autumn96 cantly. Kämmerer reports several times that the Z5 Zuse 1953.July97 power consumption of the Oprema was only 30 to ALWAC Logistics Res. 1953.December (?) 40 Watts for the machine alone, without the lamps G 2 Billing 1955.Spring98 at the control desk. He never mentions the electric Oprema Kämmerer 1955.Summer motor which drove the cam shaft. It is therefore a bit difficult to compare this rather low power As has been discussed above in connection with consumption with that of other relay computers; the several dates regarding Oprema, ASCC/Mark I e.g. Z3: 4 kW, Z4: 4 kW and Z5: 5 kW. The mo- and ENIAC, it is not always easy to give precise tor, which drove the shaft of the ASCC/Mark I, dates for the different relevant events in the life of consumed about 3 kW.101 The relay contacts were these early computers. For the Zuse computers I always switched in current-free mode which re- follow Zuse who said: “It [the Z3; JW] was com- duced the wear of the contacts significantly; only pleted in 1941 and was the first fully operational the contacts of the cam shaft had to be checked machine to contain state-of-the-art versions of all regularly and maybe replaced.102 the important elements of a program-controlled A peculiarity of the Oprema was the use of computing machine for scientific purposes.”; i.e. plugboards as program storage. It had the draw- Zuse himself does not see his first two experi- back that the “loading” of a program was rather mental models, Z1 (1938) and Z2 (1940), as com- cumbersome and error-prone. In his work diary puters. On the other hand, IFIP writes in 1994: Lenski reports that Kämmerer had the idea to “Prof. Zuse, who designed the Z1, "the first employ plugging templates to facilitate the loading working programmable computer," in 1935-6,”. of programs, but it seems that such templates had Raul Rojas wrote that the Z1 “has been called the never existed.103 On the ENIAC, where program- first computer in the world”. The date for Zuse’s ming may have been even rather more cumber- Z4 is a presentation at the Aerodynamics Research some, the Burkses remark: “While the ENIAC Institute in Göttingen just before Easter 1945, could compute the 30-second trajectory of a shell when Zuse was on his way from Berlin to the in 20 seconds, operators required 2 days to pro- Alps. In the following years it was occasionally gram it to do so.“104 used for different computations, e.g. in 1948 for On the other hand, the program in the Oprema commercial calculations for the alpine dairy coop- was thus stored in the machine, which allowed erative Lehern in Hopferau, and its productive use arbitrary conditional and unconditional jumps and began in August 1950 at the Institute for Applied therefore also the execution of loops.105 As has Mathematics of the Swiss Federal Institute of been discussed above, the programs for optical Technology (ETH Zurich) as the first computer in 99 calculations were of a highly repetitive nature. The Switzerland. down-time caused by program loading could be The date for the ALWAC (Axel Lennart Wen- reduced by plugging-in a second program in the ner-Gren Automatic Computer) comes from a unused parts of the program tables while the ma- survey of the Office of Naval Research (ONR). chine was executing the first program.106 This The information in this survey “was obtained, for worked well as long as the total length of the the most part, during the month of February 1953, several programs did not exceed the limit of 300 …”. This means, that “December 1953” seems to instructions. be an estimate made by Logistics Research, Inc. of Redondo Beach, California, early in 1953. On the Post-history other hand, the journal “Electrical Engineering” in For the creation of the Oprema K&K were award- May 1954 reports that the ALWAC has been nd 107 unveiled, without giving any date. Logistics Re- ed the 2 Class National Prize on 7 Oct. 1955. search was formed in 1952 by the Swedish indus- After the completion of the Oprema Kämmerer trialist Axel Lennart Wenner-Gren, who had also worked on the design of two further computer founded the "Verkehrsbahn-Studiengesellschaft models, the ZRA 1 and the ZRA 2. The ZRA 1 [Transit Railway Study Group]“ in Cologne- was produced in a small series of about 32 ma- Fühlingen, Germany, in 1951, which developed a chines in the years 1959 to 1963. It was about 40 monorail train system, the ALWEG-Bahn. In times faster than one Oprema machine. The ZRA 2 January 1953 the Verkehrsbahn- was still in the development stage when the project Studiengesellschaft was renamed “Alweg- was abandoned at the end of 1961. Both of them Forschung, GmbH [Alweg Research Corpora-
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 22 were electronic computers whose logic circuits Munich on 23 October 1991 (Fig. 18). In 1994 were based on magnetic cores.108 Konrad Zuse, who also had artistic abilities and K&K left CZJ at the end of 1959. Kortum who had once pondered to become an advertising became the director of the newly created Central artist, created a chalk drawing of Kämmerer. Institute for Automation (ZIA) in Jena and Wilhelm Kämmerer died on 15 August 1994 after Kämmerer became his deputy. When ZIA in Jena he had suffered a heart attack shortly after his 89th was closed on 31 March 1961 Kämmerer became birthday.113 the director of a newly created satellite facility of As mentioned above, Kortum became director the Institute of Mathematics of the Academy of of the Central Institute for Automation in Jena on Sciences.109 1 Jan. 1960. When the institute in Jena was closed Beginning in autumn 1956 Kämmerer gave a on 31 March 1961, Kortum became the director of series of courses on “program-controlled comput- the newly created Forschungsstelle für Meßtechnik ers” and “information theory” as an associate und Automatisierung (FMA) der Akademie der lecturer at the FSU in Jena. On 11 Dec. 1958 he Wissenschaften [Research Center for Measure- completed the “Habilitation” [a postdoctoral quali- ment Technology and Automation of the Academy fication] at the FSU with the thesis “Ziffernre- of Sciences]. On 1 Nov. 1960 Kortum became a chenautomat mit Programmierung nach mathe- Lecturing Professor for Control Engineering and matischem Formelbild [Digital computer automa- Automation at the Institute of Technology in ton programmed with mathematical formulæ]”. On Ilmenau, while his main occupation remained the 1 August 1960 he became a Lecturing Professor work at ZIA resp. FMA. He held this lectureship (Professor mit Lehrauftrag) at the FSU and contin- for the following 10 years. During the 1960s Kor- ued to give courses on computers, cybernetics, tum worked on bolometers, vacuum thermopiles, information theory and related topics, while his pyrometers, infrared detectors and similar devices. main occupation remained the work at ZIA resp. In 1959 he had become a member of the Central the Academy of Sciences. These teaching activi- Research Council (Forschungsrat) of the GDR and ties ended with his retirement in the summer on 19 Jan. 1960 he became the first president of 1970.110 In the 1960s and 1970s Kämmerer pub- the newly founded Deutsche Messtechnische lished several books on computers and cybernet- Gesellschaft (DMTG) [German Association for ics.111 In the 1960s K&K, together with Helmut Measurement Technology]. In addition to the Thiele, were the editors of the German edition of National Prize in 1955 Kortum received the fol- the Soviet publication Problemy kibernetiki.112 lowing awards: Together with Thiele Kämmerer started the Jour- 1967 Medal of Merit of the GDR nal “Elektronische Informationsverarbeitung und 1971 Merited Technician of the People Kybernetik: EIK [Electronic Information Pro- 1971 Gold Medal at the Leipzig Spring Trade Fair cessing and Cybernetics]“ in 1965. In 1970 he was for his vacuum thermopile. elected to the Leopoldina, one of the oldest exist- Due to a very serious illness Kortum prematurely ing scientific academies. After reunification retired from the FMA in 1971. Herbert Kortum died on 28 September 1979 shortly after his 72nd birthday.114
Is Herbert Kortum a Computer Pioneer? In his work diary Lenski mentions Kortum several times: “1954.04.09 new room plan presented to Dr. Kortum … Kortum: the required space area is quite large, could it be done in a different way? … Endurance tests for the relays should be started immediately, according to his experience the switching of the relays is absolutely reliable. 1954.04.27 Dr. Kortum proposes wire contacts made of silver. 1954.05.06 Dr. Kortum will initiate preliminary talks about the delivery of the relays. 1954.05.13 Meeting at Dr. Kortum’s: told to prepare a schedule, a cost estimate and a quanti- ty estimate.
rd 1954.05.14 Drafts of schedule and cost estimate Figure 18. Kämmerer (3 from right) receives the Konrad presented to Dr. Kortum. Zuse Medal; Zuse second from right. Courtesy of GI Bonn. 1954.05.15 Copy of the wiring diagram to Dr. Kortum. Schedule and cost estimate for meeting Kämmerer was awarded the Konrad Zuse Medal in Berlin delivered. of the Gesellschaft für Informatik (German Infor- matics Society, GI), which was presented to him in
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 23 (On 17 May 1954 Kortum presented the Oprema editor of a series of books on the technology of project to minister Rau in Berlin (East), as men- planning, were he authored a book on computer tioned above.) aided project planning. In 1991, Jänike was 1954.05.18 Meeting at Dr. Kortum’s: construction awarded the Konrad Zuse Medal of the Zentral- approved. Immediately begin with the work on a verband Deutsches Baugewerbe (ZDB) [Central large scale. Association of German Building Industry ].117 1954.06.10 Dr. Kortum informed of the current The German computer pioneer Lehmann state by telephone. (1921−1998), who has already been mentioned in 1954.06.12 Meeting at Dr. Kortum’s about the the chapter “Design and Construction” above and account number, additional personnel and the who knew Kortum and his work quite well, quite required space. strongly opposed Genser’s and Jänike’s view in a 1954.06.15 Dr. Kortum is looking for a drafts- letter to Jänike dated 19 March 1995, when “Ger- woman. man Computer Pioneers” was still in the prepara- 1954.08.30 Dr. Kortum did an inspection and tion period. Lehmann refers to the several works asked for a list of the reasons which caused the by Kortum mentioned throughout the current delay. paper and comes to the conclusion: 1954.09.04 Meeting at Dr. Kortum’s: at the visit “Damit gehört Kortum sicher zu den ver- of the plant manager next week, a plan should be dienstvollen Förderern des Einsatzes von Re- ready which “guarantees” that both machines chentechnik in seinem Industriebereich (also will be completed on time. insbes. in den Zeiss-Werken), ein Pionier der 1954.09.10 Dr. Kortum is informed that the whole Rechentechnik/Informatik wurde er damit jedoch department ELG M can work for us. nicht. [Thus, Kortum certainly belongs to the 1954.09.11 Meeting at Dr. Kortum’s: told to deserving promotors of the use of data processing develop a detailed plan by 18 Sep. The plan in his industrial sector (i.e. espec. at the Zeiss should have a granularity of 3 days. works), this, however, did not make him a pioneer 1954.09.17 Meeting at Dr. Kortum’s: plan is OK. of computing/informatics]”. 1954.09.18 (Saturday) Dr. Kortum intends to Lehmann developed a series of electronic check the adder circuits on Sunday. computers at the Dresden Institute of Technology 1954.09.29 Dr. Kortum is informed that the esti- and was awarded the Konrad Zuse Medal of the mated costs are about 1.4 million Marks. He Gesellschaft für Informatik (German Informatics says that when the machine is completed nobody Society, GI) in 1989.118 will mention this figure. Lehmann’s view is also corroborated by a 1954.10.04 (Monday) Dr. Kortum spotted some publication list published by the Institute of Tech- incorrectly packaged relays on Sunday. nology in Ilmenau which for the years 1963 to 1954.10.11 Dr. Kortum is informed that the mill- 1967 cites 25 publications by Kortum on automa- ing machine is to be taken away. tion, cybernetics, thermo-elements, bolometers and 1954.11.04 Dr. Schrade, Dr. Kortum and RuMü similar items. Two of these papers were co- made a visit.” authored with a second author. One of these two These entries show that Kortum’s role in the papers is a survey article on “Digitale Infor- Oprema project was essentially a managerial one. mationsmaschinen (Rechenautomaten) [Digital This is no surprise, but is explained by the fact that Information Machines (Computing Automata)] co- Kortum, as Chief of Development, was responsi- authored with Fritz Straube, one of the developers ble for all products of CZJ, from small photo- of the ZRA 1.119 graphic lenses to the huge planetariums. Seven And even Jänike supports Lehmann’s view development labs reported directly to Kortum, when citing Mühlhausen as follows: “Kortum als among them ELQ, Kämmerer’s lab, which was Entwicklungshauptleiter ist der Initiator der Re- one of the smaller labs.115 chenmaschinenentwicklung. … Kämmerer ist der Nevertheless, there are publications which see theoretische Kopf der Entwicklung. [Kortum, as Kortum as one of the computer pioneers in Ger- the Chief of Development, initiated the develop- many, e.g. the 2013 book “Hommage an Konrad ment of the computers. … Kämmerer was the Zuse [Homage to Konrad Zuse]” by Friedrich leading theoretician of the development.]” Leh- Genser. This claim occurred first in the forerunner mann discussed the role of Kortum also in a letter publication “German Computer Pioneers” which to Jänike dated 23 Dec. 1994 and wrote “Kortum was published privately (300 copies) by Johannes war der Manager [Kortum was the manager].”120 Jänike and Genser in 1995. It was initiated, fi- Kämmerer himself seemed to be obliged to nanced and edited by Genser and the texts of the mention that Kortum had also been involved in the biographies were written by Jänike.116 Oprema project when he (Kämmerer) prompted a Johannes Jänike (1921−2015) studied civil correctional note in the MTW-Mitteilungen 1957 engineering at the Institute for Architecture and No.1. In the paper “Die programmgesteuerte …” Civil Engineering in Weimar in the mid-1950s. (see endnote 30) of 1956 Kämmerer had only During an excursion in 1954 he saw the Oprema, mentioned himself.121 which was then under construction. He later Summing up, we may call Kortum a pioneer worked as a planning engineer and was also the computer initiator, as John Ronald Womersley has
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 24 been called by Brian E. Carpenter and Robert W. the FSU on 25 October 2008, organized primarily Doran.122 by Michael Fothe. Elsner, a former Zeiss employ- ee, who’s now head of his own company, collected a whole bunch of material from Klaus Lösche, a Conclusion former operator of the Oprema, and from the Zeiss Despite the fact that it was technologically a late- archives. Since I was a complete novice to Zeiss comer the Oprema was an important step in the and the Oprema, I could not have given this talk developing of computing at CZJ and the GDR at without Elsner’s help. In 2014, my colleague large. It improved the development of optical Klaus Küspert invited me to give a talk on the systems significantly and paved the way to better Oprema at an alumni event in Jena on 25 October lens systems. It also paved the way to the ZRA 1 2014. This then led to the decision to try to write a whose 32 exemplars were running in 15 universi- somewhat more detailed account of the develop- ties and 15 other institutes and companies GDR- ment of this machine. Eberhard Dietzsch, a former wide during the 1960s. Immo O. Kerner, who was lens designer at CZJ, advised me on optical calcu- involved in the design of ZRA 1, estimated that lations and provided me with Fig. 16 and 17. more than 15,000 students learnt programming and For their assistance during my search for the basics of computing through this computer, information and source material I also thank Helga and furthermore, that about 50,000 people had Kämmerer, Jena, the elder daughter of Wilhelm close contact with a ZRA 1 during their education Kämmerer; Klaus Lösche, Jena; Johannes Jänike or professional life. The development of Oprema (), Jena; Wolfgang Koch of Friedrich Schiller also paved the way to Kämmerer’s publications, University Jena, who gave me one of the Oprema which have already been mentioned throughout relays which he had inherited from his father; this paper.123 Marte Schwabe and Wolfgang Wimmer of the Similarly to the Oprema, the current paper Zeiss archives, Jena; Margit Hartleb and Rita itself also seems to be a kind of latecomer, because Seifert of the archives of the Friedrich Schiller Jänike and Lehmann discussed in early 1995 the University Jena; Wilhelm Füßl and Matthias idea to publish the history of the early computers Röschner of the archives of the Deutsches Muse- in the GDR in the Annals. On 12 Feb. 1995 Jänike um Munich; Kerstin Weinl of the library of the wrote in a letter to Lehmann that he had received a Technical University Munich; Bernhard letter from “Mr. Williams, University of Calgary, Braunecker, emeritus of Leica Geosystems Heer- Alberta, Kanada” accompagnied by many attach- brugg; Jürg Dedual, the creator of the Virtual ments. Michael Roy Williams was at that time Archive of Wild Heerbrugg; Martin Gutknecht, professor in the Department of Computer Science emeritus of the ETH Zürich; Monika Schulte of at the University of Calgary and Assistant Editor- the Gesellschaft für Informatik, Bonn; Manfred in-Chief of the IEEE Annals of the History of Eyßell, Göttingen; and Horst Zuse, the eldest son Computing. Jänike proposed that Lehmann should of Konrad Zuse. write about the computer history in Saxony and he would write about the computer history in Thu- About the Author ringia. Lehmann signaled his consent in principle Jürgen F. H. Winkler is Professor Emeritus at Frie- in a letter dated 1 March 1995. Jänike answered on drich Schiller University Jena. During his career at 9 March 1995 and proposed that each of them KIT Karlsruhe, Siemens Corporate Research Mu- should draw up a concept for a “Special Issue of nich and Friedrich Schiller University Jena he worked and published on programming languages the Journal Annals of the History of Computing“ and software engineering. In his farewell lecture in on the “History of Computing in East Germany“. October 2008 he recalled the Oprema and has His concept has the date 16 March 1995 and lists 6 since then also worked on the history of computers. papers whose authors should be he himself, Leh- Read more at http://psc.informatik.uni-jena.de/. mann or Mühlhausen. However, it seems that this plan did not materialize: none of these papers did appear in the Annals, especially not in the issue Endnotes/References 1999, No. 3, which contained a number of papers on early computers in several countries of Eastern Europe. In 2012 a survey paper by James W. Cortada about information technologies in the DMA: Archives of the Deutsches Museum GDR was published in the Annals, which men- UACZ, BACZ: Archives of CZJ tions the Oprema briefly in one paragraph and UAJ: University Archives Jena gives the numbers of relays erroneously as 25,000. 1 As mentioned above, both Oprema machines K. Zuse, The Computer – My Life, Springer, Ber‐ together contained 16,626 relays.124 lin, Heidelberg, 1993, 978‐3‐642‐08151‐4, p. 62. 2 W. Kämmerer, “Mein Weg zum Computerpionier Acknowledgments [My Way Becoming a Computer Pioneer]”, un‐ First of all, I have to thank Georg Elsner, who published typescript, Jena, May 1990, pp. 2−3. gave me the decisive nudge to give a talk on the 3 W. Kämmerer, “Lebenslauf [Curriculum Vitae]”, Oprema as my farewell lecture at a symposium at 19 April 1956, UAJ D 815 f. 5v; H. Kortum, “Gu‐
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 25
tachten über Wilhelm Kämmerer wg. Berufung 10 H. Kämmerer, “Wilhelm Kämmerer – Das Leben zum Direktor des Instituts für Mathematik an des Computerpioniers – [Wilhelm Kämmerer – der Hochschule für Elektrotechnik Ilmenau [Let‐ The Life of the Computer Pioneer –]“, Jenaer ter of Recommendation for W. Kämmerer on Jahrbuch zur Technik‐ und Industriegeschichte, Behalf of His Possible Appointment as Director Band 14 [Jenaer Yearbook on the History of of the Department of Mathematics at the Insti‐ Technology and Industry, vol. 14], M. Steinbach, tute of Electrical Engineering in Ilmenau]“, UAJ ed., Verlag Vopelius, Jena, 2011, 978‐3‐939718‐ D 815 f. 25r. 61‐1, pp. 287−366, here p. 302; A. Hermann, 4 Kämmerer, “Mein Weg zum Computerpionier”, Carl Zeiss – Die abenteuerliche Geschichte einer p. 5; Personnel review by R. Weiß, UAJ D 815, f. deutschen Firma [Carl Zeiss – The Adventurous 32r. History of a German Company], Piper Verlag, 5 File of the PhD‐procedure of Herbert Kortum, München Zürich, 1992, 978‐3492112659, pp. UAJ N 8 ff. 314−322. 10, 12. 11 6 J. Jänike and H. Kämmerer, Die Insel des G. Lenski, “Reisebericht – Fahrt mit LKW durch Vergessens [The Island of Forgetting], un‐ das amerikanisch besetzte Gebiet Deutschlands published manuscript, Jena, Oct. 2001, p. 25. vom 7.10.45 bis 3.11.45 [Trip Report – Trip by 7 W. Wimmer, “Forschung und Entwicklung bei Truck Through the US‐occupied Zone of Germa‐ Zeiss in der Zwischenkriegszeit [Research and ny from 7 Oct. 1945 to 3 Nov. 1945]“, Len/Stk Development at Zeiss in the Interwar Period]”, 25.11.1945, UACZ, BACZ VA 006258 ff. 564−574, Jenaer Jahrbuch zur Technik‐ und Industrieges‐ here f. 570. 12 chichte, Band 12 [Jenaer Yearbook on the Histo‐ W. Mühlfriedel and E. Hellmuth, Carl Zeiss in ry of Technology and Industry, vol. 12], M. Jena 1945 – 1990, [Carl Zeiss in Jena 1945 – Steinbach, ed., Glaux Verlag, Jena, 2009, 978‐3‐ 1990], Böhlau, Köln, Weimar, Wien, 2004, 3‐ 940265‐24‐1, endnote 16. 412‐11196‐1, p. 24; Jänike and Kämmerer, Die 8 UACZ, BACZ, Namenskartei [Names catalogue]: Insel des Vergessens, p. 179. 13 “Kortum”; “Kurzchronik der Konstruktionsbüros K. Schumann, “Aktenvermerk zu Flu‐ (EBos), Konstruktionsbüro Kortum [Short Histo‐ gzeugzielgeräten vom 31.10.1945 [Memo on ry of the Development Labs, Development Lab aircraft sighting devices, 31 Oct. 1945]“, UACZ, Kortum]”, UACZ, BACZ 16631. BACZ 15272. It is interesting to learn that Soviet 9 H. Kortum, “Kreiselvisiere [Gyroscopic Sights]”, military personnel had back then the idea to fly Lilienthal‐Gesellschaft, Bericht 153, Berlin, 1942, to America. An even more direct remark is re‐ pp. 72−86; H. Kortum, ”Ein Kreiselhorizont be‐ ported by the former Soviet reparations officer sonderer Art [A Gyroscopic Sight of a Special Vladimir Shabinsky: “A Soviet colonel laughed Kind]“, Feingerätetechnik (0014‐9683), vol. 7, and said [in 1945; JW]: “The Americans gave us no. 2, 1958, pp. 63−71; “Na onalpreisträger this [The German underground rocket factory in Dr. Herbert Kortum 50 Jahre alt [National Prize the Harz Mountain near Nordhausen; JW]. But Winner Dr. Herbert Kortum 50 Years Old]“, in five or ten years, they will cry. Imagine when Feingerätetechnik, vol. 6, no. 11, 1957, pp. 531– our rockets fly across the ocean!““ , Look (0024‐ 532; F. Kurowski, Luftwaffe Aces: German Com‐ 6336), vol. 22, no. 3, 1958, p. 21; H. Kortum, bat Pilots of World War II. Stackpole Military “Kreiselvisiere” and “Ein Kreiselhorizont be‐ History Series, Stackpole Books, 2004, sonderer Art”. 14 9780811731775, p. 250; anon., Lotfernrohr 7 B, K. Schumann, “Aktenvermerk zu Flu‐ C, C/D und D, LUFTFAHRT International (0343‐ gzeugzielgeräten vom 12.2.1946 [Memo on air‐ 3943), vol. 5, 1974, pp. 701−714; for the inter‐ craft sighting devices, 12 Feb. 1946]”, UACZ, rogation of Kortum see: W. W. E. Samuel, BACZ 15272; on the return of Kortum to Jena: American Raiders: The Race to Capture the Kämmerer,“Wilhelm Kämmerer “, mentions Luftwaffe's Secrets, Univ. Press of Mississippi, that Kortum returned in Jan. 1946 to Jena, p. 2004, 9781604731361, pp. 453−454, Note 16; 302; a memo on the history of the development the translation “level‐ and dive‐bombing aiming labs states that Kortum returned “kurz vor der device“ is adapted from C. W. Cain, Fighters of Demontage [briefly before the dismantling]”, World War II, Exeter Books, 1979, UACZ, BACZ 16631, EHL/Hse/Fdl 23.10.53, this 9780896730267, p. 25; on E. Udet and dive‐ memo dates the beginning of the dismantling bombing see e.g G. Bracke, Melitta Gräfin Stauf‐ on 22 Oct. 1946; a list of people deported in the fenberg: Das Leben einer Fliegerin [Melitta summer of 1945 from Jena to Heidenheim con‐ Countess Stauffenberg: The Life of an Aviatrix], tains the entry “34. Dr. Kortum, Herbert am F. A. Herbig, München, 2013, 978‐3‐7766‐2707‐ 20.2.46 nach Jena zurück [back to Jena on 20 7, pp. 60−61. Feb. 1946]“, UACZ, BACZ VA 006258 f. 403.
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15 “Russische Kommission Juli 1945 – Oktober man Scientists Behind Red Barbed Wire], 1946 [Russian Commission July 1945 – October Deutsche Verlags‐Anstalt, Stuttgart, 1993, 3‐ 1946]“, UACZ, BACZ 15272. 421‐06635‐3, p. 337, mid 1953: Mühlfriedel and 16 K. Schumann, “Aktenvermerk zu Flu‐ Hellmuth, Carl Zeiss in Jena 1945 – 1990, pp. gzeugzielgeräten vom 2.11.1945 [Memo on air‐ 114–115. craft sighting devices, 2 Nov. 1945]“, UACZ, 22 Magnus, Raketensklaven, p. 344; Kämmerer, BACZ 15272, this memo is now the earliest “Mein Weg zum Computerpionier”, p. 6; Mühl‐ document mentioning the Oprema; K. Schu‐ friedel and Hellmuth, Carl Zeiss in Jena 1945 – mann, “Aktenvermerk zu Flugzeugzielgeräten 1990, pp. 44−45; Jänike and Kämmerer, Die In‐ vom 6.11.1945 [Memo on aircraft sighting de‐ sel des Vergessens , p. 47; on the so‐called “spe‐ vices, 6 Nov. 1945]“, UACZ, BACZ 15272. cialists“ see e.g. W. Albring, Gorodomlia – 17 F. Ortlepp, Zeiss‐Chronik Band 3 [History of Zeiss Deutsche Raketenforscher in Rußland – [Go‐ Vol. 3], unpublished typescript, Jena, 1954, p. rodomlia – German Rocket Scientists in Russia 650; K. Schumann, “Niederschrift Nr. 22 über −], Luchterhand, Hamburg, Zürich, 1991, 3‐630‐ Besprechung vom 17.8.1946 [Minutes No. 22 of 86773‐1; K. Berner, Spezialisten hinter Stachel‐ the Meeting at 17 Aug. 1946]“, UACZ, BACZ draht [Specialists Behind Barbed Wire], Bran‐ 15135; W. Kämmerer and H. Kortum, “Oprema, denburgisches Verlagshaus, Berlin, 1990, 3‐ die programmgesteuerte Zwillings‐ 327‐00672‐5, see e.g. pp. 213−240; M. Uhl, “Das Rechenanlage des VEB Carl Zeiss Jena [Oprema, Ministerium für Bewaffnung der UdSSR und die the program‐controlled twin‐computer of the Demontage der Carl Zeiss Werke in Jena ‒ eine VEB Carl Zeiss Jena]“, Feingerätetechnik, vol. 4, Fallstudie [The Ministry of Armament of the no. 3, 1955, pp. 103−106. USSR and the Dismantling of the Carl Zeiss 18 K. Schumann, “Niederschrift Nr. 22 über Be‐ Works in Jena − A Case Study]”, R. Karlsch and J. sprechung vom 17.8.1946“; IBM Deutschland Laufer, eds., Sowjetische Demontagen in GmbH, Kleine Chronik der IBM Deutschland Deutschland 1944 ‒ 1949 [Sowjet Dismantlings 1910 – 1985 [Short History of IBM Germany in Germany 1944 ‒ 1949], Duncker & Humblot, 1910 – 1985], 5. ed., IBM Form D 12‐0017‐7 Berlin, 2002, 3‐428‐10739‐X, pp. 113−145, here (12/86), pp. 8, 9, 66. p. 114, FN. 3. 19 “Verzeichnis der im Oktober 1946 nach der 23 Kämmerer,“Wilhelm Kämmerer “, pp. 318−321; Sowjetunion verpflichteten Zeiss‐Mitarbeiter on the cooling‐off period see e.g. Heinemann‐ [List of the Zeiss personnel obliged in Oct. 1946 Grüder and Wellmann, Die Spezialisten, pp. 46, to work in the Soviet Union]“, UACZ, BACZ 81−82 and Max Steenbeck, Impulse und Wir‐ 6730; F. Ortlepp, Zeiss‐Chronik Band 3, p.612; kungen [Impulses and Effects], Verlag der Na‐ E.‐H. Schmitz, Handbuch zur Geschichte der tion, Berlin [East; JW], 1977, p. 308. Optik [Handbook of the History of Optics], Vol. 24 Kämmerer,“Wilhelm Kämmerer “, p. 324; H. 5, Part C, J. P. Wayenborgh, Oostende, 1993, p. Kortum, “Erfahrungs‐ und Rechenschaftsbericht 868. über die Lage der Forschung und Entwicklung 20 H. Kämmerer,“Wilhelm Kämmerer “, pp. im VEB Carl Zeiss Jena [Experience and Account 303−305; U. Albrecht, A. Heinemann‐Grüder of the Situation of Research and Development and A. Wellmann, Die Spezialisten – Deutsche in the VEB Carl Zeiss Jena]”, May 1958, UACZ, Naturwissenschaftler und Techniker in der Sow‐ BACZ 24500, pp. 98−99. jetunion nach 1945 [The Specialists – German 25 Kämmerer,“Wilhelm Kämmerer “, p. 324. Scientists and Technicians in the Soviet Union 26 A. Jones, “Five 1951 BBC Broadcasts on Auto‐ after 1945], Dietz Verlag Berlin, 1992, 3‐320‐ matic Calculating Machines“, IEEE Annals Hist. 01788‐8, p. 12; N.M. Naimark, The Russians in Comp. (1058‐6180), vol. 20, no. 2, 2004, pp. Germany − a history of the Soviet Zone of occu‐ 3−15; pation, 1945‐1949, Belknap Press of Harvard http://downloads.bbc.co.uk/historyofthebbc/ University Press, 1995, 0674784057, p. 222. 1940s.pdf, retr. 2015Aug13; H. Carpenter, The 21 “Verzeichnis der im Oktober 1946 nach der Envy of the World – Fifty Years of BBC Third Pro‐ Sowjetunion verpflichteten Zeiss‐Mitarbeiter“; gramme and Radio 3 – 1946 – 1996, Weidenfeld Kämmerer, “Wilhelm Kämmerer “, p. 310; there and Nicholson, London, 1996, p. 106. are also authors who give a different time peri‐ 27 Kämmerer,“Wilhelm Kämmerer“, pp. 326–329; od for the stay on Gorodomlia: arrival on 20 UACZ, BACZ, Namenskartei: “Kortum”. June 1953: Heinemann‐Grüder and Wellmann, 28 Kämmerer, “Mein Weg zum Computerpionier”, Die Spezialisten, p. 109, arrival on 25 June 1953: p. 7; N. J. Lehmann, “Zur Geschichte des »Insti‐ K. Magnus, Raketensklaven – Deutsche Forscher tuts für maschinelle Rechentechnik« der Tech‐ hinter rotem Stacheldraht [Rocket Slaves – Ger‐ nischen Hochschule/Technischen Universität
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 27
Dresden [On the History of the Institute of Au‐ 34 “DM” is here the currency of the GDR and not tomatic Computing of the Institute of Technolo‐ the Deutschmark which was usually also re‐ gy/Technical University Dresden]“, p.123, E. ferred to by the acronym “DM”. From 24 June Sobeslavsky and N. J. Lehmann, Zur Geschichte 1948 until 31 July 1964 the official name of the von Rechentechnik und Datenverarbeitung in GDR‐Mark was “Deutsche Mark der Deutschen der DDR 1946−1968 [On the History of Compu‐ Notenbank (DM) [German Mark of the German ting and Data Processing in the GDR Treasury (DM)]”, Bundesministerium für ge‐ 1946−1968], Hannah‐Arendt‐Institut, Dresden, samtdeutsche Fragen (Hrsg.), SBZ von A bis Z, 1996, pp. 123−157; H. H. Golds ne and A. Gold‐ Bonn, 1966, Deutscher Bundes‐Verlag, 10. Aufl., stine, “The Electronic Numerical Integrator and p. 519 [Federal Department for All‐German Af‐ Computer (ENIAC)“, Mathematical Tables and fairs, ed., SBZ from A to Z, German Federal Pu‐ Other Aids to Computation (MTAC, 0891‐6837), blishing House, Bonn, 10th ed., 1966]. vol. 2, no. 15, July 1946, pp. 97‐110, Lehmann 35 T. P. Hughes, “ENIAC: Invention of a Computer”, erroneously cites this as MTAC vol. 2, no. 13 Technikgeschichte (0040‐117X), vol. 42, no. 2, (April 1946), Lehmann, “Zur Geschichte des »In‐ 1975, pp. 148−165, here pp. 156−157. stituts für maschinelle Rechentechnik«“, p. 154. 36 H. Thiele, Carl Zeiss Jena ‒ Entwicklung und 29 G. Lenski, “Arbeitsberichte [Work Reports]“, Beschreibung der Photoobjektive und ihre Erfin‐ UACZ, BACZ 27995; E. Mühlhausen, “Am An‐ der [Carl Zeiss Jena ‒ Development and Descrip‐ fang war OPREMA . . . [In the Beginning was tion of the Photographic Lenses and their Inven‐ OPREMA . . .]“, rechentech‐ tors], 2nd ed., privately published, München, nik/datenverarbeitung (0300‐3450), vol. 24, no. 2007, p. 37; telephone conversation between E. 7, 1987, pp. 34−36; Jänike and Kämmerer, “Die Dietzsch and the author, 14 May 2018. Insel des Vergessens“, p. 154. 37 Invitation to and other material about the 30 LWD, 6 and 8 April 1954; W. Kämmerer and H. Oprema Party, UACZ, BACZ 27995. Kortum, “Oprema, die programmgesteuerte 38 MDR (Mitteldeutscher Rundfunk [Broadcasting Zwillings‐Rechenanlage des VEB Carl Zeiss Je‐ Service of Central Germany]), “Einblicke – 150 na”; W. Kämmerer, “Die programmgesteuerte Jahre Carl Zeiss [Insights – 150 Years Carl Rechenanlage „Oprema“ [The program‐ Zeiss]”, 13 Nov. 1996, 20:15 (30 minutes), here controlled computing device „Oprema“]“, position 17:45; Invitation to and other material MTW‐Mitteilungen, vol. III, no. 5, 1956, pp. 127‐ about the Oprema Party. 132; W. Kämmerer, Ziffernrechenautomaten 39 K. Schumann, “Begründung für einen Antrag auf [Digital Computing Automata], Akademie‐ Auszeichnung der wissenschaftlichen Mi‐ Verlag, Berlin, 1960, p. 121; IEEE Std 754™‐ tarbeiter des VEB Carl Zeiss Jena, Dr. Herbert 2008, sect. 2.1.49; ISO/IEC/IEEE 60559: Kortum und Dr. Wilhelm Kämmerer, mit dem 2011(en), sect. 2.1.49; D. E. Knuth, Seminumeri‐ Nationalpreis [Rationale for a petition to award nd cal Algoritms, 2 ed., Addison‐Wesley, Reading the National Prize to the scientists Dr. Herbert et al, 1981, 0‐201‐03822‐6, pp. 198−199. Kortum and Dr. Wilhelm Kämmerer of VEB Carl 31 R. (?) Dietrich, Memo 29. 3. 1955, UACZ, BACZ Zeiss Jena]“, 13 April 1955, p. 4, UACZ, BACZ No. 19570. 19570; W. Kämmerer, “Ausführlicher Ab‐ 32 Ministerium für Maschinenbau [Ministry of schlußbericht – Feinjustierung der Oprema [De‐ Machine Building], Sekretariat des Ministers tailed and final report – Vernier adjustment of [Office of the Minister], Memo 19 May 1954; H. the Oprema], 15 Jan 1956, p. 4, UACZ, BACZ Kortum, “Trip Report”, 20 May 1954; H. Kor‐ 21563. tum, ”Kurze Zusammenfassung des Vortrages 40 UACZ BI 02448, 5 Jan. 1955; see also endnote zur Oprema, gehalten vor Min. Rau am 17.5.54 37; E. Mühlhausen, “OPREMA und ZRA 1 − [Short summary of the presentation given to Frühe Entwicklungen der digitalen Rechentech‐ minister Rau on 17 May 1954]“, p. 1; all in nik im Zeisswerk Jena [OPREMA and ZRA 1 − UACZ, BACZ 23789. Early Developments of Digital Computing in the 33 J.F.H. Winkler, “Konrad Zuse und die Optik‐ Zeiss Works Jena]”, Kramer, Lothar, ed., Jenaer Rechenmaschine in Jena [Konrad Zuse and the Jahrbuch zur Technik‐ und Industriegeschichte Optic Computer at Jena]”, Log In (0720‐8642), Band 2 [Jenaer Yearbook on the History of Tech‐ no. 166/167, 2010, pp. 132−136; J.F.H. Winkler, nology and Industry, vol. 2], Glaux‐Verlag, Jena, “Konrad Zuse and Switzerland”, Swiss Physical 1999, 3‐931743‐10‐1, S. 109−127, here pp. Society, SPS Communications, no. 34, 2011, pp. 112−113; the Oprema people may have known 42−44; for the slides of two talks about the the Cornel‐Trio version of the song “Bravo, bra‐ Oprema see http://psc.informatik.uni‐ vo, beinah wie Caruso [Bravo, bravo, almost like jena.de/hist/oprema.htm , retr. 2019Apr05. Caruso]”,
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 28
https://www.youtube.com/watch?v=2QQnE_HJ 0‐19‐957814‐6, pp. 1−6, here p. 1; A. E. Sale, EQ4, retr. 23 Sept. 2018; J. G. Brainerd, “Project “Lorenz and Colossus”, Proceedings of the 13th PX―The ENIAC“, Pennsylvania Gazette vol. 44, IEEE Computer Security Foundations Workshop, no. 7 (1946), pp. 16−17 as cited in T. Haigh, M. 2000, pp. 216‐222, here p. 222; B. J. Copeland, Priestley and C. Rope, ENIAC in Action, The MIT ed., Colossus , p. 62; T. Haigh and Mark Priest‐ Press, Cambridge & London, 2018, 978‐ ley, Colossus and Programmability, IEEE Ann. 80262535175, p.32. Hist. Comp., vol. 40, no. 4, 2018, pp. 5−27; A. R. 41 W. Kämmerer, “Ausführlicher Abschlußbericht”, Burks and A. W. Burks, The First Electronic Com‐ p. 13; A. Jung, “5 Jahre “Oprema“ [5 years puter – The Atanasoff Story, The Univ. of Michi‐ “Oprema“]”, undated typescript, private archive gan Press, Ann Arbor, 1988, 0‐472‐10090‐4, p. of Klaus Lösche, p. 1; F. Bolz, “Das Zeiss‐ 1; A. W. Burks and A. R. Burks, “The ENIAC: …”, Rechenzentrum in vier Jahrzehnten [The Zeiss p. 388; B. L. Stuart, Simulating the ENIAC, Proc. Computing Center in Four Decades]”, re‐ of the IEEE (0018‐9219), vol. 106, no. 4, pp. chentechnik/datenverarbeitung, vol. 26, no. 10, 761−772. 1989, pp. 5−10, here p. 5. 48 B. Randell, ed., The Origins of Digital Comput‐ 42 W. Kämmerer and H. Kortum, “Oprema, die ers, p. 201. programmgesteuerte Zwillings‐Rechenanlage 49 H. Rutishauser, A. Speiser and E. Stiefel, Pro‐ des VEB Carl Zeiss Jena”, p. 103; E. Mühlhausen, grammgesteuerte digitale Rechengeräte (el‐ “Am Anfang war OPREMA . . .”, p. 35; E. Mühl‐ ektronische Rechenmaschinen) [Program‐ hausen, “OPREMA und ZRA 1”; I. O. Kerner, controlled Digital Computing Devices (Electronic “OPREMA und ZRA 1 – die Rechenmaschinen Computers)], Birkhäuser Verlag, Basel, 1951; F. der Firma Carl Zeiss Jena [OPREMA and ZRA 1 – L. Alt, Review, MTAC vol. 6, no. 39, 1952, p. The Computing Machines of the Carl Zeiss Com‐ 186. pany Jena]”, F. Naumann and G. Schade, eds., 50 J. G. Brainerd, „Genesis of the ENIAC“, Techno‐ Informatik in der DDR – eine Bilanz [Informatics logy and Culture (0040‐165X), vol. 17, no. 3 (Jul., in the GDR: An Assessment], Gesellschaft für 1976), pp. 482‐488, here p. 483; T. P. Hughes, Informatik, Bonn, 2006, 978‐3‐88579‐420‐2, pp. “ENIAC”, p. 153; A. W. Burks and A. R. Burks, 147─177, here p. 147. “The ENIAC”, p. 331; R. Burks and A. W. Burks, 43 www.cl.cam.ac.uk/conferences/EDSAC99/, retr. The First Electronic Computer, pp. 362–378. 23 Feb. 2007. 51 T. H. Flowers, “The Design of Colossus”, p. 241. 44 T. H. Flowers, “The Design of Colossus”, Annals 52 F. R. Michael, “Tube Failures in ENIAC”, Elec‐ Hist. Computing (0164‐1239), vol. 5, no. 3, tronics (0013‐5070), vol. 20, no. 10, 1947, pp. 1983, pp. 239─252, here p. 245. 116−119; T. H. Flowers, “The Design of Colos‐ 45 http://www‐ sus”, p. 247; W. Kämmerer, Ziffernrechenauto‐ 03.ibm.com/ibm/history/exhibits/markI/markI_ maten, p. 121. chronology3.html, retr. 28 Aug. 2016; C. J. 53 B. J. Copeland (ed.), Colossus , pp. 286, 288. Bashe, L. R. Johnson, J. H. Palmer and E. W. 54 T. P. Hughes, “ENIAC”, p. 154. Pugh, IBM’s Early Computers, The MIT Press, 55 I. B. Cohen, Howard Aiken: Portrait of a Compu‐ Cambridge and London, 1986, 0‐262‐02225‐7, p. ter Pioneer, The MIT Press, Cambridge & Lon‐ 27. don, 1999, 0‐262‐03262‐7, p. 115; C. J. Bashe et 46 B. Randell, ed., The Origins of Digital Comput‐ al.: IBM’s Early Computers, pp. 26, 27. ers, Third Ed., Springer, Berlin etc., 1982, 0‐387‐ 56 Anon.,” Allgemeine Prinzipien [Basic Princi‐ 11319‐3, pp. 297, 353; J. G. Brainerd, “Genesis ples]”, 8 pages, Doc.‐No. 54‐3197, 8−19 June of the ENIAC”, Technology and Culture (0040‐ 1954, UACZ, BACZ 27995; Anon., 165X), vol. 17, no. 3 (Jul., 1976), pp. 482‐488, “Grundgedanken zur Konstruktion der Oprema here pp. 486, 487; A. W. Burks and A. R. Burks, [Basic Ideas on the Design of Oprema]”, 9 pag‐ “The ENIAC: First General‐Purpose Electronic es, UACZ, BACZ 27995; W. Kämmerer, “Die Computer”, Annals Hist. Computing, vol. 3, no. Oprema: (Prinzip, Aufbau und Arbeitsweise) 4, 1981, pp. 310−389, here pp. 336, 346; T. [The Oprema: Principle, Structure and Principle Haigh, M. Priestley and C. Rope, ENIAC in Ac‐ of Operation]”, 9 pages, 6 October 1954, UACZ, tion, pp. 79−81. BACZ 27995; W. Kämmerer, “Der Nockensender 47 B. Randell, “Colossus: Godfather of the Com‐ [The Pulse Generator]”, 3 pages, 19 October puter”, B. Randell, ed., The Origins of Digital 1954, UACZ, BACZ 27995; Anon., “Der Mul‐ Computers, pp. 349−354; J. Copeland, “Intro‐ tiplikationsablauf, Divisionsablauf, Das duction”, B. J. Copeland, ed., Colossus – The Se‐ Wurzelziehen [The Procedures for Multiplica‐ crets of Bletchley Park’s Codebreaking Comput‐ tion, Division and Extraction of the Square ers, Oxford, Oxford University Press, 2010, 978‐ Root]”, 4 pages, UACZ, BACZ 27995; W.
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 29
Kämmerer, “Die programmgesteuerte Re‐ 65 C. Babbage, „Of the Mathematical Powers of chenanlage im VEB Carl Zeiss Jena”, Die Technik the Calculating Engine“, B. Randell, ed., The Or‐ (0040‐1099), Messesonderheft 1955, pp. 7−9, igins of Digital Computers, pp. 19−54, here pp. UACZ, BACZ 14506; W. Kämmerer and H. Kor‐ 43−44; M. V. Wilkes, Babbage as a Computer tum, “Oprema”; W. Kämmerer, “Die pro‐ Pioneer, The Babbage Memorial Meeting, 18 grammgesteuerte Relaisrechenanlage „Opre‐ October 1971, British Computer Soc. & Royal ma“”; W. Kämmerer, “Die Relaistechnik am Re‐ Statistical Soc., London, 1971, pp. 1−18, here chenautomaten Oprema des VEB Carl Zeiss Jena p.9. [The Relay Technology of the Computing Au‐ 66 R. K. Richards, Arithmetic Operations in Digital tomaton Oprema of VEB Carl Zeiss Jena]”, Computers, pp. 292−295. Feingerätetechnik, vol. 7, no. 1, 1958, pp. 67 IEEE Std 754™‐2008, sect. 4.3.1.; J. H. Wilkin‐ 13−20. son, Rounding Errors in Algebraic Processes, Do‐ 57 F.L. Alt, “A Bell Laboratories' Computing Ma‐ ver Publ., New York, repr. 1994, 0‐486‐67999‐3, chine‒I”, MTAC, vol. 3, no. 31, 1948, pp. 1‒13, p. 4. here p. 1; K. Zuse, “Patentanmeldung Z391 68 W. Kämmerer, Ziffernrechenautomaten, pp. (1941) [Patent Application Z391 (1941)]”, R. 129‒130. Rojas, ed., Die Rechenmaschinen von Konrad 69 J. F. Reiser and D. E. Knuth, “Avoiding the drift Zuse [The Computers of Konrad Zuse], Springer, in floating‐point addition“, Inf. Proc. Letters Berlin, 1998, 3‐540‐63461‐4, pp. 111‒193; U.S. (0020‐0190) vol. 3, no. 3, 1975, pp. 84−87. Patent 3,120,606, “Electronic Numerical Inte‐ 70 J. B. Scarborough, Numerical mathematical grator and Computer”, Feb. 4, 1964; T. Haigh, analysis, Oxford & IBH Publishing Co., New Del‐ M. Priestley and C. Rope, ENIAC in Action, p. ix. hi et al., 1930, p. 2; A. W. Burks, H. H. Goldstine 58 G. M. Hopper,“The First Bug“, Annals Hist. and J. von Neumann, Preliminary Discussion of Comp., vol. 3, no. 3, 1981, pp. 285−286. the Logical Design of an Electronic Computing 59 A similar picture of September 1946 shows two Instrument. The Institute for Advanced Study, people wiring inside the Harvard Mark II walk‐ 28 June 1946, p. 28. in relay units, I. B. Cohen and G. D. Welch, 71 W. Kämmerer, Ziffernrechenautomaten, p. 125. Makin‘ Numbers – Howard Aiken and the Com‐ 72 W. de Beauclair, Rechnen mit Maschinen [Com‐ puter, MIT Press, Cambridge & London, 1999, 0‐ puting With Machines], Friedr. Vieweg & Sohn, 262‐03263‐5, p. 218m. Braunschweig, 1968, 60 DBP 1 011 963, filed 22 Sep. 1955, patented 23 (https://archive.org/details/rechnenmitmaschid Oct. 1958. ebe), p. 103. 61 K. Zuse, The Computer – My Life, p. 42; L. T. y 73 H. H. Aiken, ed., A Manual of Operation for the Quevedo, “Essays on Automatics”, B. Randell, Automatic Sequence Controlled Calculator, Har‐ ed., The Origins of Digital Computers, pp. vard University Press, Cambridge, Mass., 1946, 89−107. p. 18. 62 W. Kämmerer, “Die Relaistechnik ...“, p. 13. 74 Drawing by E. Dietzsch in November 2017; H. 63 E. Stiefel, “La machine a calculer «Z4» de l’École Thiele, Carl Zeiss Jena, p. 14 (Flektogon), p. 37 Polytechnique Fédérale a Zurich (Suisse) et sa (E. Dietzsch); E. Dietzsch, Die Entwicklungsge‐ application a la résolution d’une équation aux schichte der Retrofokusobjektive vom Typ dérivées partielles de type elliptique [The calcu‐ »Flektogon« [The History of the Development of lating machine «Z4» of the Federal Institute of the Retrofocus Lenses of the Type »Flektogon«], Technology in Zurich (Switzerland) and its appli‐ Jenaer Jahrbuch zur Technik‐ und Industriege‐ cation to the solution of an elliptic partial diffe‐ schichte ‐ Band 4, Glaux Verlag Jena, 2002, 3‐ rential equation]“, Centre National de la Re‐ 931742‐56‐X, pp. 108−130; for the op cal theo‐ cherche Scientifique, ed., Les machines à calcu‐ ry see e.g. W. T. Welford, Aberrations of the ler et la pensée humaine, Paris, 1953, pp. 33−40, Symmetrical Optical System, Academic Press, here p. 36; H. Rutishauser, A. Speiser and E. London etc., 1974, 0‐12‐742050‐9. Stiefel, Programmgesteuerte digitale Re‐ 75 see e.g. D. Choi, A. Pazylbekova, W. Zhou, P. van chengeräte, p. 28; R. Rojas, “Konrad Zuse’s Leg‐ Beek, Improved Image Selection for Focus acy: The Architecture of the Z1 and Z3”, IEEE Stacking in Digital Photography, 2017 IEEE In‐ Annals Hist. Comp., vol. 19, no. 2, 1997, pp. ternational Conference on Image Processing 5−16, here p. 7. (ICIP), pp. 2761 − 2765. 64 R. K. Richards, Arithmetic Operations in Digital 76 W. Kämmerer, “Die programmgesteuerte Re‐ Computers, Van Nostrand, Princeton et al., sixth laisrechenanlage „Oprema“”, p. 130. printing, Aug. 1957, p. 257. 77 W. Kämmerer and H. Kortum, “Oprema …”, p. 103; the report “A Survey of Automatic Digital
JFH Winkler Oprema – The Relay Computer of Carl Zeiss Jena 30
Computers” of the Office of Naval Research, 2007, 978‐3‐940265‐06‐7, pp. 73−104; A. Jung, Washington, 1953, contains for several relay “5 Jahre “Oprema“”, p. 9. computers and electronic computers figures 89 “Drei Jahre Oprema [Three years Oprema]“, which characterize their reliability. 1958, typescript, private archive of K. Lösche, p. 78 P. Ceruzzi, Reckoners : the prehistory of the 1. digital computer, from relays to the stored pro‐ 90 A. Jung, “5 Jahre “Oprema“”, p. 8, Appendix III. gram concept, 1935‐1945, Greenwood Press, 91 G. R. Stibitz and E. Loveday, “The Relay Compu‐ Westport, Conn., 1983, 9780313233821, p. 65. ters of Bell Labs, Part Two“, Datamation (0011‐ 79 David A. Grier, When Computers Were Human, 6963), vol. 13, no. 5, 1967, pp. 45‒49, here p. Princeton University Press, 2013, 49. 9781400849369. 92 H. Rutishauser, A. Speiser and E. Stiefel, Pro‐ 80 W. Kämmerer, “Ausführlicher Abschlußbericht grammgesteuerte … , p. 96; K. Zuse, My Life, p. “. 123. 81 H. Rutishauser, A. Speiser and E. Stiefel, Pro‐ 93 J.F.H. Winkler, “Konrad Zuse und die Optik‐ grammgesteuerte digitale Rechengeräte, Sect. Rechenmaschine in Jena”, p. 134. 4.9; Harvard University, Computation Laborato‐ 94 H. Kortum, “Kreiselvisiere“, pp. 72−86; W. ry, Description of a Relay Calculator, Cambridge, Kämmerer and H. Kortum, “Oprema …”, p.103; Mass., 1949; Eckert‐Mauchly Computer Corp., Kämmerer, “Mein Weg zum Computerpionier”, THE BINAC, 1949; A. A. Auerbach, J. P. Eckert, p. 7; H. Kortum,“Zur Entwicklung der modernen Jr., F. Shaw, J. R. Weiner and L. D. Wilson, “The Rechentechnik”; M. Schramm, “Präzision als Binac”, Proc. IRE vol. 40, no. 1, 1952, pp. 12−29. Leitbild? − Carl Zeiss und die deutsche Innovati‐ 82 W. Kämmerer, “Die programmgesteuerte onskultur in Ost und West, 1945‐1990 [Precision Relaisrechenanlage ”Oprema“”, p. 132. as Model? − Carl Zeiss and the German Culture 83 A. Jung, “5 Jahre “Oprema“ [5 years “Opre‐ of Innovation in East and West, 1945‐1990]”, ma“]”, undated typescript, private archive of K. Technikgeschichte, vol. 72, no. 1, pp. 35−49 , Lösche, p. 2. here p. 38; MDR, Einblicke – 150 Jahre Carl 84 A. Jung, “5 Jahre “Oprema“ “, p. 1; H. Kortum, Zeiss, 20:18−21:04. “Erfahrungs‐ und Rechenschaftsbericht”, pp. 95, 95 Harvard University, Computation Laboratory, 99; F. Straube, “Die Oprema und ihre Erfolge Description of a Relay Calculator, p. xi; R. Camp‐ [The Oprema and its achievements]”, Der bell, “Mark II, an Improved Mark I”, I. B. Cohen Scheinwerfer, 18 October 1955, UACZ, BACZ and G. W. Welch, eds., Makin’ Numbers, pp. 22623; W. Kämmerer, “Ausführlicher Ab‐ 111‒127, here p. 113; D. H. Hook and J. M. schlußbericht”, p. 4. Norman, Origins of Cyberspace, historyof‐ 85 H. Kortum, “Zur Entwicklung der modernen science.com, Novato, Calif., 2002, 0‐930405‐85‐ Rechentechnik [The evolution of the modern 4, #1296; http://computer.org/computer‐ computing technology]”, Der Scheinwerfer, 11 pioneers/pdfs/B/Billing.pdf , retr. 16 Nov 2014; June 1959; W. Mühlfriedel and E. Hellmuth, Encyclopædia Britannica Ultimate Reference Carl Zeiss in Jena 1945 – 1990, p. 177; K. Mütze, Suite, Version 2013.00.00.000000000, entry on Die Macht der Optik – Industriegeschichte Jenas Wilkes, Sir Maurice Vincent. 1846−1996, Band II [The power of optics – In‐ 96 H. Billing, “Die Göttinger Rechenmaschinen G1, dustrial History of Jena 1846−1996, Vol. II]. G2, G3 [The Göttingen Computers G1, G2, G3]”, quartus‐Verlag, Bucha bei Jena, 2009, 978‐3‐ D. Wall (Ed.), Entwicklungstendenzen wissen‐ 936455‐78‐6, p. 70. schaftlicher Rechenzentren [Development 86 If one shift is 8 hours then there would be 136 Trends in Scientific Computing Centers], Spring‐ hours per week and 1360 hours in 10 weeks, er, Berlin, 1980, 3‐540‐10491‐7, pp.1−13, here but the figure in Kämmerer’s report is 1320. p. 7. 87 W. Kämmerer, “Ausführlicher Abschlußbericht”, 97 H. Zuse, Konrad Zuses Werk [The Works of pp. 9, 11. Konrad Zuse], DVD V. 2.1.7 v. 28.1.2008, Konrad 88 C. Hofmann, “Der Einfluss von Paul Rudolph Zuse Multimedia‐Show, picture 394. und Harry Zöllner auf die Entwicklung der 98 L. Biermann, “Überblick über die Göttinger Fotoobjektive [The influence of Paul Rudolph Entwicklungen, insbesondere die Anwendung and Harry Zöllner on the development of pho‐ der Maschinen G 1 und G 2”, A. Walther and W. tagraphic lenses]”, Jenaer Jahrbuch zur Technik‐ Hoffmann (eds.), Elektronische Rechenmaschi‐ und Industriegeschichte, Band 10 [Jenaer Year‐ nen und Informationsverarbeitung [Electronic book on the History of Technology and Industry, Computing Machines and Information Pro‐ vol. 10], M. Steinbach, ed., Glaux Verlag, Jena, cessing], Nachrichtentechnische Fachberichte, Beihefte der NTZ Band 4 – 1956 , Friedr. Vieweg
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& Sohn, Braunschweig, 1956, pp. 36−39; M. 108 W. Kämmerer, “Mein Weg zum Computerpion‐ Eyßell, “Heinz Billing – der Erbauer der ersten ier”, pp, 8, 9; M. Judt, Der Innovationsprozeß deutschen Elektronenrechner (Teil 1) [Heinz Bill‐ Automatisierte Informationsverarbeitung in der ing – The architect of the first German electron‐ DDR von Anfang der fünfziger bis Anfang der ic computers (Part 1)]” , GWDG‐Nachrichten siebziger Jahre [The Innovation Process “Auto‐ (0940‐4686), vol. 33, no. 4, 2010, pp. 9−36. matic Information Processing” in the GDR from 99 H. Zuse, Konrad Zuse Multimedia‐Show, picture the Beginning of the 1950s to the Beginning of 361; E. Stiefel, “La machine a calculer «Z4» ...“, the 1970s], Dissertation, Humboldt Univ., Berlin, p. 37; K. Zuse, The Computer – My Life, pp. 61, 1989, Part 1, pp. 45, 46; E. Mühlhausen, “Am 62; M. Eyßell, “Der Erfinder des Computers: Anfang war OPREMA . . .“; I. O. Kerner, “OPRE‐ Konrad Zuse (Teil 1) [The inventor of the com‐ MA und ZRA 1”. puter: Konrad Zuse (Part 1)]”, GWDG‐ 109 W. Kämmerer, “Mein Weg zum Computerpion‐ Nachrichten, vol. 33, no. 1, 2010, pp. 6−20, ier”, p. 9. here p. 19; Zuse KG, 25 Jahre Zuse [25 Years 110 University Calendars of the Friedrich Schiller Zuse], Bad Hersfeld, 1961, p. 31; IFIP Newsletter University, Jena, 1956−1968; W. Kämmerer, vol. 11, no. 4, 1994, p. 3; R. Rojas, “Konrad “Mein Weg zum Computerpionier”, p. 9, 11. Zuse’s Legacy: The Architecture of the Z1 and 111 http://d‐nb.info/gnd/1019559446, retr. 9 May Z3”, IEEE Ann. Hist. Comp., vol. 19, no. 2, 1997, 2017. pp. 5−16, here p. 5. 112 http://d‐nb.info/457852976, retr. 9 May 2017. 100 Office of Naval Research, A Survey of Automat‐ 113 W. Kämmerer, “Mein Weg zum Computerpion‐ ic Digital Computers, 1953, pp. vi, 3; anon., ier”, p. 9; “Low‐Cost Digital Computer for Engineering Use https://www.leopoldina.org/de/mitglieder/mitg Unveiled”, Electrical Engineering (0095‐9197), liederverzeichnis/member/4063/, retr. 16 May vol. 73, no. 5, 1954, pp. 481−482; M. W. 2017; K. Zuse, The Computer – My Life, p. 21; F. McMurran, ACHIEVING ACCURACY: A Legacy of Genser, Hommage an Konrad Zuse[Homage to Computers and Missiles. Xlibris Corporation, Konrad Zuse], Superbrain Verlag, Düsseldorf & 2008, 9781462810659, p. 139; Balje, 2013, 978‐3‐9815891‐1‐5, pp. 9, 191; H. http://alweg.de/alwegcologne.html retr. 25 Kämmerer, “Wilhelm Kämmerer”, pp. 360, 363, Aug. 2017; M. H. Weik, A Survey of Domestic 364. Electronic Digital Computing Systems, Dept. of 114 anon., “Nationalpreisträger Dr. Kortum zum the Army, Ballistic Research Laboratories (BRL), Professor ernannt [National prize laureate Dr. Report No. 971, Dec. 1955, p. 3. Kortum appointed professor]”, Feingerätetech‐ 101 W. Kämmerer, “Die programmgesteuerte nik, vol. 10, no. 4, 1961, pp. 180‒181; anon., Rechenanlage …”, p. 9; W. Kämmerer, “Die pro‐ “Gründung der Deutschen Meßtechnischen Ge‐ grammgesteuerte Relaisrechenanlage „Opre‐ sellschaft [Formation of the German Association ma“”, p. 127; H. Zuse, Konrad Zuses Werk; H. H. for Measurement Technology]”, ELEKTRIE Aiken, ed., A Manual of Operation ..., p. 11. (0013‐5399), vol. 15, no. 4, 1961, p. U63; K. 102 W. Kämmerer, “Die Relaistechnik …”, p.15. Junge et al., Obituary for Herbert Kortum, 103 G. Lenski, “Arbeitsberichte“, 7 and 8 April Feingerätetechnik, vol. 29, no. 1, 1980, pp. 1954. 46−47; H.‐G. Lauenroth and W. Fritzsch, “In 104 A. W. Burks and A. R. Burks, “The ENIAC: …”, p. memoriam Prof. Dr. Herbert Kortum”, msr 311. (Messen, Steuern, Regeln) (0026‐0347), vol. 23, 105 W. Kämmerer, “Die programmgesteuerte no. 3, 1980, pp. 166−167; J. Jänike and H. Relais‐Zwillings‐Rechenanlage „Oprema“ des Kämmerer, Die Insel des Vergessens, pp. 27, 28, VEB Carl Zeiss Jena [The program‐controlled 48. twin‐relay‐computer „Oprema“ of the VEB Carl 115 Organization Chart, UACZ, BACZ 01169. Zeiss Jena]”, N. J. Lehmann (ed.), Aktuelle 116 F. Genser, Hommage an Konrad Zuse, pp. Probleme der Rechentechnik [Current Problems 202‒209; J. Jänike and F. Genser, Die Ver‐ of Computational Technology], Proc. of a Collo‐ gangenheit der Zukunft: deutsche Computerpi‐ quium in Dresden, 22−27 Nov. 1955, Deutscher oniere [The Past of the Future: German Comput‐ Verlag der Wissenschaften, Berlin, 1957, pp. er Pioneers], 2nd expanded ed., self‐published, 15−16. Düsseldorf, 1995; letter from Jänike to Lehmann 106 W. Kämmerer, “Die programmgesteuerte 9 Dec. 1994, DMA NL 183/252. Relaisrechenanlage „Oprema“”, p. 130. 117 J. Jänike, “Vom Wismut‐Schacht in den Hörsaal 107 anon., “Unsere Nationalpreisträger 1955 [Our [From the Wismut Pit into the Lecture Hall]”, National Prize Winners]”, Feingerätetechnik, Thesis (1433‐5735), vol. 49, no. 6, 2003, pp. vol. 4, no. 11, 1955, p. 501. 56−64; J. Jänike, Einführung in die automatis‐
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ierte Projektierung [Introduction to the Auto‐ matic Project Planning], Verl. für Bauwesen, Berlin, 2nd ed., 1970; for other publications of J. Jänike see: http://d‐nb.info/gnd/106422413, retr. 15 Jun 2017; ZDB Direkt, Sonderausgabe 2005, p. 15. 118 On Lehmann and his works see e.g. N. J. Leh‐ mann, “Zur Geschichte des »Instituts für mas‐ chinelle Rechentechnik« …“ and http://d‐ nb.info/gnd/120148943, retr. 22 Aug 2017; Lehmann’s letter: J. Jänike and H. Kämmerer, Die Insel des Vergessens, pp. 209‒210 and DMA NL 183/252. 119 Institute of Technology Ilmenau, Bibliographie der Veröffentlichungen von Angehörigen der Technischen Hochschule Ilmenau aus den Jahren 1963−1967 [Bibliography of Members of the Institute of Technology Ilmenau in the years 1963−1967], pp. 39−41; H. Kortum and F. Straube, “Digitale Informationsmaschinen (Re‐ chenautomaten) [Digital Information Machines (Computing Automata)]”, G. Berndt, St. Fronius, W. Häußler, H. Kortum and C. Tränkner, eds., Taschenbuch Maschinenbau, Band 1 Grundla‐ gen [Handbook of Mechanical Engineering, Vol. 1, Fundamentals], VEB Verlag Technik Berlin, 1965, pp. 1356−1404. 120 J. Jänike and H. Kämmerer, Die Insel des Vergessens, p. 155; N. J. Lehmann, letter to J. Jänike, 23.12.94, DMA NL 183/251. 121 Berichtigung [Corrigendum], MTW‐ Mitteilungen, vol. IV, no. 1, 1957, p. 25. 122 B. E. Carpenter and R. W. Doran, “John Wo‐ mersley: Applied Mathematician and Pioneer of Modern Computing“, IEEE Ann. Hist. Comp., vol. 36, no. 2, 2014, pp. 60−70, here p. 68. 123 I. O. Kerner, “OPREMA und ZRA 1”, pp. 170−171; H. Adler, J. Bormann, W. Kämmerer, I. O. Kerner and N. J. Lehmann, Mathematische Maschinen [Mathematical Machines], H. Sachs, ed., Entwicklung der Mathematik in der DDR [Development of Mathematics in the GDR], vol. 4, VEB Deutscher Verlag der Wissenschaften, Berlin, 1974, pp. 714−732, here p. 722. 124 For the letters of Jänike and Lehmann and Jänike’s concept see DMA NL 183/252; http://www.cips.ca/MichaelWilliams , retr. 11 Nov. 2018; J. W. Cortada, “Information Techno‐ logies in the German Democratic Republic (GDR), 1949–1989“, IEEE Ann. Hist. Comp., vol. 34, no. 2, 2012, pp. 34−48, here p. 37.
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