“I have always taken the position that there is enough credit for everyone in the invention and development of the electronic computer” – John Atanasoff to reporters.

Professor John Atanasoff and graduate student Clifford Berry built the world’s first electronic-digital computer at Iowa State University between 1939 and 1942. The Atanasoff-Berry Computer represented several innovations in computing, including a binary system of arithmetic, parallel processing, regenerative memory, and a separation of memory and computing functions.

Presper Eckert and John Mauchly were the first to patent a digital computing device, the ENIAC computer. A patent infringement case (Sperry Rand Vs. Honeywell, 1973) voided the ENIAC patent as a derivative of John Atanasoff’s invention. Atanasoff was quite generous in stating, “there is enough credit for everyone in the invention and development of the electronic computer.” Eckert and Mauchly received most of the credit for inventing the first electronic-digital computer. Historians now say that the Atanasoff-Berry computer was the first.

“It was at an evening of scotch and 100 mph car rides,” John Atanasoff told reporters, “when the concept came, for an electronically operated machine, that would use base-two (binary) numbers instead of the traditional base-10 numbers, condensers for memory, and a regenerative process to preclude loss of memory from electrical failure.”

John Atanasoff wrote most of the concepts of the first modern computer on the back of a cocktail napkin. He was very fond of fast cars and scotch.

ABC computer Atanasoff-Berry Computer

Atanasoff-Berry Computer

In late 1939, John Atanasoff teamed up with Clifford Berry to build a prototype. They created the first computing machine to use electricity, vacuum tubes, binary numbers and capacitors. The capacitors were in a rotating drum that held the electrical charge for the memory. The brilliant and inventive Berry, with his background in electronics and mechanical construction skills, was the ideal partner for Atanasoff. The prototype won the team a grant of $850 to build a full-scale model. They spent the next two years further improving the Atanasoff-Berry Computer. The final product was the size of a desk, weighed 700 pounds, had over 300 vacuum tubes, and contained a mile of wire. It could calculate about one operation every 15 seconds, today a computer can calculate 150 billion operations in 15 seconds. Too large to go anywhere, it remained in the basement of the physics department. The war effort prevented John Atanasoff from finishing the patent process and doing any further work on the computer. When they needed storage space in the physics building, they dismantled the Atanasoff-Berry Computer.

During his study of civil engineering in the Technical College of Berlin Charlottenburg (Technischen Hochschule) Konrad Zuse faced a serious problem, while studying the construction of buildings and roads. This type of constructions require solving of huge systems of linear equations, which was very hard to be done by means of a logarithmic rule or even mechanical calculator of this time. Some time in 1934 the young Kuno (as

his friends called him) started thinking about computers. After the graduation in 1935, he started as a design engineer at the Henschel Flugzeugwerke (Henschel aircraft factory) in Berlin-Schönefeld, but resigned a year later, deciding to devote entirely to the construction of a computer.

Kuno arranged a workshop in the apartment of his parents and decided to devote entirely to the construction of the computer. Initially he was helped not only by his parents, who allowed him to use the largest room of their apartment as a workshop, and gave him some money, but also by his sister Lieselotte, and several of his fellow-students and friends. Thus he managed to collect several thousand marks for materials, moreover some of them practically helped his in the workshop. The most innovative was his friend Helmut Schreyer (1912-1984), which will play important role in the construction of the Zuse’s computers.

The first computer of Konrad Zuse—V1 (Z1)

In 1936 Zuse finished the logical plan for his first computer, the V1 (V for Versuchsmodell—experimental model). Actually all the first computers of Zuse was named with V (V1 to V4), but after the WWII he changed their names to Z1 to Z4, in order to avoid the nasty association with the V1-V4 military rockets. The manufacturing begin in the same year and the prototype was ready in 1938 (see the lower photo), making the Z1 the first relays computer in the world.

Construction of the Z1 in the apartment of Zuse’s parents

Z1 was a machine of about 1000 kg weight, which consisted from some 20000 parts. It was a programmable computer, based on binary floating point numbers and a binary switching system. It consisted completely of thin metal sheets, which Kuno and his friends produced using a jigsaw. The only electrical unit was an electrical engine with power 1kW, which was used to provide a clock frequency of one Hertz (one cycle per second), actually it had also a crank for manually cycling the machine. Z1 consisted of 6 basic units: Control unit; Arithmetical unit; Input/Output; Memory; Memory selector; Tape reader (see the lower drawing).

The punch tape and punch tape reader are used for programming of Z1. The control unit supervised the whole machine and the execution of the instructions. The arithmetic unit (with two registers—R1 and R2) was an adder, and all of the operations were internally reduced to additions or subtractions. The memory, which consisted of 64 words, each containing 22 bits, was formed from three blocks. The first block contained 64 words for the exponents and signs (8 bits for each word). The other two blocks each contained 32 words for the mantissa (14 bits for each word). The selection unit interpreted the address for the memory, managed by the control unit. The input device was a keyboard, numbers were presented to the machine in a decimal form with an exponent, then they were converted to binary normalized floating point representation and transferred to the memory. Similarly, the output device converted the binary floating point number in Register R1 into a decimal number with an exponent and showed them on a annunciator.

A block of Z1 (© Horst Zuse)

The Z1’s programs (Zuse called them Rechenplans) were stored on punch tapes by means of a 8-bit code. The instruction set of the Z1 consisted of eight instructions as follows:
1. Two instructions for input/output:
•Lu—to call the input device for decimal numbers
•Ld—to call the output device for decimal numbers
2. Two instructions for reading/writing from/to memory:
•Pr z—read the contents of the memory cell z into Registers R1 or R2
•Ps z—write the contents of Register R1 to the memory cell z
3. Four arithmetical instructions:
•Ls1—add the two floating-point numbers in the Registers R1 and R2
•Ls2—subtract the two floating-point numbers in the Registers R1 and R2
•Lm—multiply the two floating-point numbers in the Registers R1 and R2
•Li—divide the two floating point numbers in the Registers R1 and R2

The first reliable model—Z2

When in 1936 Konrad invited his friend Helmut Schreyer (see the lower photo) to come and see his machine, Helmut came, saw his strange plates and expressed spontaneously: “You have to do this with tubes.” First reaction of Kuno was negative— “this is another one of the mad schnapsideas (drink ideas) of my friend!”. With tubes can be built radio equipment, but calculating machines? Almost at the same time the same the idea came to the mind of the american physicist John Atanasoff, and he namely will be the first man to build an electronic computer (ABC computer).

The young engineers Konrad Zuse (left) and Helmut Schreyer (right)

Zuse and Schreyer continued to work together on the mechanical models, but Schreyer’s idea was not dead. Schreyer wrote his doctoral thesis on this topic at the Institute for Research of the Technical University Berlin Charlottenburg and created several logical circuits with tubes. In 1938 Zuse and Schreyer demonstrated the electronic circuits to some german scientists, and even exposed their idea of building an electronic computer, but when they mentioned that such a device will require some 2000 tubes and several thousand glow lamps, this was categorizes as a “fantasy”. The largest electronic devices of this time consisted from several hundred tubes. Later on Schreyer will try again in vain to interest the authorities in their work, proposing to the army to build an electronic computer for the airforce from about 2000 tubes, but when he explained that 2 years will be enough to manufacture the machine, the reaction was “We will won the war long before your computer will be ready, why bother?”.

Zuse was unsatisfied with the reliability of the binary switching metal sheets used in the Z1, especially in the arithmetical unit. He was acquainted with relays, used in telecommunications, but namely Schreyer was the one, who had a big experience with the relays and switching schemes as a telecommunications specialist. The friends made some some approximate considerations, but they showed, that a relays computer will require several thousands of relays, so a room full of relay cabinets seemed unacceptable to them. Besides that, the relays were too expensive for the scare funding of Zuse. That’s why he decided to construct his second computer, Z2, with arithmetic and control units made by relays, but to keep the mechanical memory of Z1 (this will also require less space). He managed to find 800 old relays from phone companies and with the help of his friends fixed them to be suitable for his purpose. These old relays will become a reason for a lot of problems with the reliability later on.

Trying to find funding, in 1937 Zuse got into contact with the former manufacturer of mechanical calculators—Kurt Pannke. The first contact was a failure, Dr. Pannke said to him: “…at the field of computing machines virtually everything, until the last possible approaches and sophisticated devices, has already been invented. There is hardly anything left to invent.” Nevertheless, Dr. Pannke agreed to visit the workshop of Zuse, and was so impressed by the his work, that decided to grant him seven thousand Reichsmark, which made possible the work to continue.

The manufacturing of Z2 began in 1938 and the prototype was ready next year. Z2 was quite similar to Z1, with the following differences:
1. The Z2’s arithmetic unit consisted of a 16-bit fixed-point engine.
2. Schreyer proposed to use a 36-mm film tape, instead of the paper tape of Z1.
3. The memory is smaller—16 cells with 16 bits each.
4. The Z2 is faster then Z1—3 Hz.

The instruction set of the Z2 consisted of the same eight instructions of Z1. Z2 worked reliable enough for arithmetic calculations. So Zuse was convinced his next computer, Z3, to be built completely out of relays.

As yearly as 1937 Zuse has already devised the ides of a full “von Neumann” type machine, despite of the fact, that his first relays computers are not “von Neumann” machines (they didn’t have the “stored-program” ability). Zuse was aware of this fault, as well as of another important one—the lack of a conditional branch instructions, but can you try to imagine a computer with 64 words memory to be a “stored-program” machine? Can you try imagine a computer, with a processor, built from metal plates, to have internal conditional branch instructions? I cannot! It was too early and Zuse didn’t have needed resources, to make such a machine.

At the same time, Zuse developed the theoretical base of his computers. He was acquainted with the binary digital system of Leibniz (so called Dyadik), but he didn’t know anything about George Bull and his algebra. He had to study not only Bull, but also the mathematical logic of Hilbert, Frege, Schröder and other logicians. Unfortunately he missed Babbage and his notation, which could make his research much easier. Finally he developed his own system and called the notation “Conditional Combinatoric” (Bedingungskombinatorik).

The first workable programmable computer in the world—Z3

In 1940 Z2 was successfully demonstrated to the Deutschen Versuchsanstalt für Luftfahrt and Zuse obtained partially funding for the development of his third computer, Z3, which he began to build in 1939. Z3 (see the lower photo) was ready in the spring of 1941, and in May, 1941, it was presented to the scientists in Berlin. Z3 and was built completely out of relays (600 for the arithmetic unit, 1400 for the memory and 400 for the control unit). In all other aspects it was similar to Z1 and Z2: it used binary numeral system and floating-point numbers, a floating-point arithmetic unit with two 22-bit registers, storage capacity of 64 words with 22 bit word length, control via 8-channel tape (i.e., a command consisted of 8 bits). The input was via a special keyboard. Output by displaying the results on light stripe including the location of the decimal commas. It was a little bit faster—5,33 Hz. The principle of work of the machine however, was improved, introducing some parallelism: a 22-bit word of data could be moved from the memory to the Register R1 and vice versa in one step (clock cycle). The same holds true for the arithmetic unit, where, amongst other things, parallel adders were used.

The reconstructed Z3 computer of Zuse in Deutschen Museum, München

The arithmetic unit of the Z3 was Zuse’s masterpiece. The instruction set of the Z3 consisted of nine instructions, the same eight instructions of Z1 and Z2, and one additional—Lw (square root). Division and square root needed 20 cycles (about four seconds), multiplication—16 cycles (about 3 seconds), addition and subtraction—less than a second. Actually internally all the arithmetic operations are reduced to addition or subtraction (subtraction is an addition of the complement of one number and the number). The multiplication algorithm is like the one used for decimal multiplication by hand. That is, it is based on repeated additions of the multiplicator according to the individual digits of the multiplicand. The division algorithm is similar to that for multiplication, except that repeated subtraction is used. The square root was calculated by a division. The Z3 included also the ability to perform arithmetic exception handling. Zuse even provided possibility of micro-sequencing and pipelining of the instructions, and a carry-look ahead circuit for the addition operation, in order to minimize the execution time (later on Zuse will improve this mechanism, designing a program look-ahead mechanism, i.e. program can read two instructions in advance, and test them to see whether memory instructions can be performed ahead of time).

The S1 and S2 Computers

After the development of Z3, Zuse received an order from his first employer—Henschel aircraft company for the development of specialized computer for measuring the surface of wings of airplanes. The machine S1 was ready in 1942 and contained approximately 600 relays and had hardware-wired programs. The company ordered another machine, which was ready in 1944. S2 was the successor of the S1, and consisted of approximately 800 relays and about 100 dial gages in order to measure the surface of the wings. The S2 can be regarded as the first process computer in the world.

The Z4 Computer

In 1942 Zuse started the development of his next computer—Z4. The goal of the Z4, was to build the prototype for a machine, that was intended to be produced in the thousands. The lack of materials however, and a tragic situation in Germany (it was wartime and Berlin was attacked almost every day by bombers), made this task almost impossible. In March 1945 Zuse eventually fled from Berlin with his pregnant wife Gisela and the semi-finished Z4 computer. He arrived at Hinterstein, Bavaria, and hid the computer in a barn. He desperately wanted to resume work on the Z4, but his first problem was to survive the years after the war. In order to get some food, he made woodcuts and sold them to the farmers and the American troops. The Z4 was reassembled as late as 1948. The next year Zuse was contacted by prof. Eduard Stiefel from ETH-Zürich, who inspected the machine and found it suitable for scientific calculations. Despite of the little bit old-fashioned technology of Z4 (at the same time in USA are developed electronic computers), Stiefel was impressed by the simplicity of programming and the powerful arithmetic unit with its exception handling capability, that’s why he decided to by the Z4. Encouraged by this, Zuse founded the his own company (Zuse KG) and started to build an improved version of Z4 for EHT, adding a conditional branch capability, instructions for printing the results on a Mercedes typewriter or a punch tape, storing numbers on the punch tape in order to transfer them into the Z4’s memory, writing results on a punch tape and others. Restoring the Z4 cost the Zuse KG about 60000 DM. The ETH paid an amount of around 100000 DM. With this money it was possible to found the Zuse KG and restore the Z4. (It is worth mentioning that the average income at this time was about 180 DM per month.) The Z4 was a great success for both the ETH and the Zuse KG.

The Z4 computer of Zuse in ETH-Zürich

The Z4 in Zürich was put in action in September 1950 and proved to be reliable. For surprise of all, the memory of Z4, consisting of thousands of metal sheets, screws and pins, was the most reliable feature of the machine. The Z4 worked very reliably and also worked during the night without supervision, something unbelievable in this time. The improved Z4 consisted of about ten relay cupboards containing 2200 standard relays, plus 21 stepwise relays for the micro-sequencer. The Z4’s memory was a mechanical one with 64 words, each containing 32 bits. The structure of the mechanical memory was similar to the memory of the Z1 (and Z2 and Z3). However, while the Z1 had a word length of 22 bits, the word length of the Z4 was extended to 32 bits. Each word was directly addressable by the instructions on the punch tape.

The Z4 made use of a unit called a Planfertigungsteil (program construction unit),which was used to produce punch tapes, containing instructions for the Z4 in a very easy way. For this reason, it was possible to learn the programming of the Z4 in as little as three hours. The Z4 had a large instruction set in order to calculate complicated scientific programs. The arithmetic processor was a powerful binary floating processor. The set of instructions is as follows:
1. Instructions for Input: <-, At1, etc.: These allow numbers to be read from the punch tape.
2. Instructions for Output: ->, D, L, etc.: These instructions cause binary numbers to be converted into their decimal equivalents and the results to be displayed with lamps, on the MERCEDES typewriter as floating or fixed point numbers, or on the punch tape.
3. Instruction for reading from memory: A n. For example A 17. This reads the contents of memory cell 17 into the Register R1. If Register R1 is occupied, then the contents are loaded into Register R2.
4. Instruction for writing to memory: S n. For example S 18. This writes the contents of Register R1 into the memory cell 18.
5. Dyadic operations: +, -, x, /, MAX, and MIN.
6. Monadic operations: x2, SQR(x), 1/x, | x | , sign(x), x*1/2, x*2, x*(-1), x*10, x*3, x*1/3, x*1/5, x*1/7, x*Pi, x*1/Pi.
7. Instructions for comparison: x = 0, x >= 0, | x | = infinity test the value in Register R1 and set Register R1 to +1 if the condition is fulfilled, if not, then the contents of Register R1 are set to –1.
8. A conditional branch instruction: SPR. The instruction SPR skips the punch tape to the instruction ST, if Register R1 contains +1 (if Register R1 contains –1 then there is no impact).
9. Instructions for switching the punch tape readers (the Z4 had two punch tape readers).

Like the Z3, the Z4 supported powerful arithmetic exception handling. The computing times were: addition and memory access, half a second; multiplication, 3 seconds; division and square root, 6 seconds; overall performance, 2000 instructions, or 1000 arithmetic operations per hour.

Zuse KG continued to manufacture relays computers—Z5 (1952), Z7 and Z11 (1954), drawing computer Graphomat Z64 (1957). As late as 1957 Zuse decided to change the relays technology with electronics. The Z22 was ready in 1958 and was an electronic computer (based on vacuum tubes), it was also the first “stored-program” computer of Zuse. In 1961 the Zuse KG launched the Z23, which was a powerful transistor computer with almost the same logic as the Z22. The next computer of Zuse was Z31, which contained a decimal arithmetic unit, and it was especially designed with banking and commercial applications in mind. In 1964 was launched the Z25 computer, which was a small and cheap machine that would be suitable for many different applications. The last computer of Zuse was Z43 (1964), a modern transistor computer with TTL logic. In 1958, Zuse designed a parallel computer, which was never built. He called it the Feldrechenmaschine (field calculation machine) consisting of 50 processors.

Konrad Zuse was a genius as an engineer, but not so good as a entrepreneur. Since the beginning of 1960s the Zuse KG got deeper and deeper into financial difficulties and in 1964 was bought by the steel company Rheinstahl, but continued to manufacture computers till 1969, when was bought by Siemens AG. The Zuse KG sold about 250 computers from 1949 to 1969 of a value of some 100 Million DM.

Plankalkül—the world’s first complete high-level language

From 1942-1946 (at the same time as he was developing the Z4 computer), Zuse was also developing ideas as to how his machines could be programmed in a very powerful way (that is, more powerful than arithmetic calculations only). In addition to pure statements for number calculations, Zuse also used rules of mathematical logic. On the one hand he used the powerful predicate logic Boolean algebra as language constructs. On the other hand he developed a mechanism to define powerful data structures, commencing with the simple bit (binary digit) and working up to complicated hierarchical structures. In order to demonstrate that the Plankalkül language could be used to solve scientific and engineering problems, Konrad Zuse wrote dozens of example programs. In his notes one can find the sorting of lists, search strategies, relations between pairs of lists… He even used more than 60 pages to describe programs for chess-playing and predicted, that in some 50 years a computer can beat the human world chess champion. It proved to be an amazingly true foresight.

Zuse used an unusual technique for the statements in Plankalkül. Each data item was denoted with V (variable), C (constant), Z (intermediate result), or R (result), an integer number to mark them, and a powerful notation was used to denote the data structure of the variable. Zuse used the word plan for program. The highlights of Plankalkül are:
1. Data types: floating point, fixed point, complex numbers; arrays; records; hierarchical data structures; list of pairs.
2. Assignment operation, for example: V1 + V2 => R1.
3. Conditional statement, for example: V1 = V2 => R1. This means: Compare the variables V1 and V2: If they are identical then assign the value true to R1, otherwise assign the value false. Such operations could also be applied on complicated data structures.
4. Possibility for defining sub-programs.
5. Possibility for defining repetition of statements (loops).
6. Logical operations (predicate logic and Boolean algebra).
7. Operations on lists and pairs of lists.
8. Arithmetic exception handling.

Helge Hansen/ TCM

The world’s largest facility for filtering carbon dioxide out of industrial emissions was inaugurated in Norway this week. While some see it as a godsend in efforts to reach environmental targets, others find the technology too dangerous and expensive.

A promise stands at the entrance: “Catching Our Future” reads the slogan Tore Amundsen hurries past.

Still, it doesn’t exactly smell like a clean future here in Mongstad, on the west coast of Norway, where a sweet-and-sour odor fills the air. “That comes from the refinery over there,” says Amundsen, pointing to a spitting gas flare. “After all, we’re in Europe’s second-largest crude-oil port here,” he adds apologetically as he shuts his helmet’s visor.

Amundsen is headed for a part of the stinking refinery sheltered from the wind, where two towers surrounded by a maze of pipes jut into the sky.

“This is where we’re capturing the future,” he says. At this moment, he is so proud that he abandons his typical Scandinavian restraint. He raves about the plant, calling it “a one-of-a-kind facility worldwide.”

Amundsen is the director of the CO₂ Technology Centre Mongstad (TCM). The plant will filter out 85 percent of the climate-damaging carbon dioxide from the emissions of the adjacent gas-fired power plant and refinery. After that, plans call for the CO₂ to be permanently stored in gas caverns. The process, known as carbon capture and storage (CCS), has never been tested on such a large scale.

A Small Gain in a Big Battle

On Monday, Norwegian Prime Minister Jens Stoltenberg and European Commissioner for Energy Günther Oettinger attended the official inauguration of the new CCS plant. Stoltenberg has characterized the plant as a milestone on the road to a climate-friendly future, calling the project “Norway’s moon landing.”

Of course, this is a slight exaggeration. Saving the global climate from the warming effect of the greenhouse gas carbon dioxide is a massive task. It gushes from steel mills, cement factories and chemical plants. But the most damaging thing to the climate is mankind’s thirst for cheap energy. “Climate-friendly wind and solar energy won’t be enough,” says Amundsen. Statistics compiled by the International Energy Agency (IEA) back his assertion: In China alone, the amount of electricity produced by burning coal has increased six-fold over the last 20 years.

At the same time, scientists note with some urgency that total greenhouse-gas emissions must be cut in half by 2050 from their 1990 level. This, they say, is the only way to stabilize the average global temperature at 2 degrees Celsius (3.6 degrees Fahrenheit) above current values. Amundsen believes that the technology in his plant can help the world solve this dilemma.

It’s no accident that the CCS plant is located in Norway. There, scientists already envision a transcontinental circulation system. In their model, future pipelines could pump carbon dioxide from Central Europe to Norway’s fjords, where it would help force natural gas out of underground deposits. The gas, in turn, would then be piped to gas-fired power plants in Germany. It was the appeal of this vision that prompted the Norwegian government to invest almost €1 billion ($1.3 billion) in the Mongstad test plant.

Other countries are also looking into ways to achieve an emissions-free future. One of the Persian Gulf states is currently planning to build a 700-megawatt gas-fired power plant outfitted with CCS technology. And China is investing billions in a pilot plant that will use coal to produce hydrogen, which in turn will be burned to generate electricity, thereby making it possible to capture the carbon dioxide before combustion.

DER SPIEGEL Graphic: The anatomy of a CCS power plant.

A Controversial Technology

But as promising as this all sounds, carbon-capture techniques are controversial, especially in Germany. Climate activists fear that energy companies merely want to use them to keep their old coal-fired plants in operation and obstruct other projects using renewable energies. Ecologists warn that the carbon dioxide could leak from underground storage sites. And politicians are afraid of citizen opposition.

A bill designed to promote CCS technology in Germany failed last year, prompting Vattenfall, the Swedish energy giant, to furiously scrap its plans for a 300-megawatt pilot power plant in the eastern state of Brandenburg. The search for permanent disposal sites has practically ground to a halt.

When German Chancellor Angela Merkel hosted an energy summit at the Chancellery last week, she mentioned CCS only once — as a cautionary tale of how politics can torpedo climate-protection technologies.

Amundsen, the TCM’s director, is undeterred by the opposition to his plant. “The realities will soon convince politicians,” he says.

The Process and the Costs

Amundsen is already focusing on the plant’s first test runs. “We can take readings at more than 100 locations,” he explains. Indeed, whether it has to do with measuring the gas’s composition, volume or conductivity, testing equipment monitors the complex cleaning procedure at every step along the way.

Two different processes are installed at the site in order to determine which is more effective in actual practice. Both processes employ a washing fluid, one containing ammonia and the other amines. While emissions bubble up the 60-meter (200-foot) tower using the amine process, they are forced through tiny holes in plates containing flowing washing fluid. The amines react with and absorb the carbon dioxide contained in the emissions. Then the mixture flows into another tower, where steam hisses through the liquid and removes the carbon dioxide so that it can be liquefied and moved into final storage.

“However,” Amundsen admits, “all of these processes consume a great deal of energy.”

Indeed, critics say this is the true Achilles’ heel of CCS technology, and even Amundsen has no illusions about it. “In a gas power plant, we lose about 8 percent efficiency,” he says, pursing his lips. “That would make the cost of electricity about 30 to 40 percent greater than it is now.”

Amundsen hopes his engineers will be able to bring down the energy consumption of the CO₂-filtering technology even further. For example, power-plant engineers at the German engineering giant Siemens have developed a promising method using a new and supposedly more effective washing substance, which could soon be tested in a third facility at Mongstad.

This new method might enable the engineers to cut energy losses in half. “But, at some point,” Amundsen says, “we’ll inevitably run up against physical limitations.”

Is CCS Worth the Extra Cost?

One can also ask whether CCS technology is even worthwhile for energy companies. As part of the emissions trading scheme, they currently have to pay about €7 per metric ton of emitted carbon dioxide. But this price is too low to make CCS worthwhile. Another key factor is the rapidly falling costs of generating renewable energy. Wind energy, in particular, is probably already cheaper today than coal- or gas-fired power plants outfitted with CCS technology.

Felix Matthes, an energy expert at the Berlin branch of the Institute for Applied Ecology, says that this is why no German electricity producer has been willing to touch the new process.

Nevertheless, Matthes is critical of German politicians for giving up on the development of large-scale CCS technology, such as that employed at the TCM plant in Norway. In fact, Matthes says there is no alternative but to use CCS for emissions from steel mills and cement factories, adding that CCS critics “have no ideas for how emissions could be reduced.” In any case, the IEA has calculated that almost 20 percent of the CO₂ reduction needed worldwide would have to be achieved through CCS technology if its implementation is to be relatively cost-efficient.

Opportunities and Optimism

Still, Matthes goes even further. In the end, he says, it would even be possible to extract carbon dioxide from the Earth’s atmosphere by using the CCS technology elsewhere, such as in wood-pellet power plants. After all, he says, trees also incorporate carbon from the atmosphere into their wood as they grow. “By burning it, capturing it and storing it underground, we reduce the concentration of the greenhouse gas in the Earth’s atmosphere,” Matthes says.

Amundsen, the TCM’s director, is pleased to hear such arguments coming from climate-protection activists. In Norway, skepticism among many experts led to less research funding than he had initially hoped for, which in turn caused the completion of the Mongstad plant to be postponed several times.

But Amundsen is optimistic about the future. “Once a product has been introduced into the market, development goes forward very quickly,” he says.

As an example, he cites developments with cell phones. In 1988, when a former employer bought him his first one, it weighed 10 kilograms (22 pounds). “And now look at this,” he says, pulling his smartphone out of the pocket of his overalls.

What is Carbon Capture & Storage?

Carbon Capture and Storage is a mitigation technology essential in tackling global climate change, and ensuring a secure energy supply.

CCS technology captures carbon dioxide from fossil fuel power stations.

The CO₂ is then transported via pipelines and stored safely offshore in deep underground structures such as depleted oil and gas reservoirs, and deep saline aquifers.

The Hard Facts behind Carbon Capture and Storage

ZEP – The Hard Facts behind Carbon Capture and Storage

For the past 40 years the world economy has run almost entirely on fossil fuels. Today, these supply over 80% of the worlds energy needs, a reality set to continue for decades to come. But while fossil fuels provide us with the stable electricity we need to power our nations and drive our economies, they also release billions of tonnes of carbon dioxide or CO2 into the atmosphere, thereby accelerating global warming.

Experts agree that we must reduce our expected emissions by at least 50% over the next 20 years. But with world energy demand expected to increase by 50% by 2030 and renewable energy to make up only ~30% of the energy mix by this date, only a portfolio of solutions can achieve this goal.

To find out more, visit:
http://www.zeroemissionsplatform.eu/the-hard-facts.html

More videos and information:
Inside CCS: the workings of CO2 capture, transport & storage
http://www.zeroemissionsplatform.eu/inside-css.html

Safe Storage: Closing the carbon loop
http://www.zeroemissionsplatform.eu/safe-storage.html

Konrad Zuse

Born June 22, 1910, Berlin-Wilmersdorf; German inventor of pre-war electromechanical binary computer designated Z1 which was destroyed without trace by wartime bombing; developed two more machines before the end of the war but was unable to convince the Nazi government to support his work; fled with the remains of Z3 to Zurich where he developed the Z4 which was successfully used at ETH. Developer of a basic programming system known as “Plankalkül” with which he designed a chess playing program. Education and Experience: By 1927 Konrad Zuse had enrolled at the Technical University in Berlin-Charlottenburg and began his working career as a design engineer (Statiker) in the aircraft industry (Henschel Flugzeugwerke) and by 1935 he had completed a degree in civil engineering. He remained in Berlin from the time he finished his degree until the end of the war in 1945, and it was during this time that he constructed his first digital computers. He later formed his own company for the construction and marketing of his designs. Honors and Awards: Honorarprofessor, Georg-August-Universitat, Göttingen), 1966; Honorary Degrees;Dr.-Ing.E.h., T.U. Berlin-Charlottenburg, 1956; Dr.rer.nat.h.c., University of Hamburg, 1979; Dr.rer.nat.h.c, T.U. Dresden, 1981; Dr.techn.h.c., Universitait Reykjavik, Iceland, 1986; Dr.rer.nat.h.c., University of Dortmund, 1991; Dr.h.c.sc.techn., ETH Eidgenossische Technische Hochschule, Zurich, 1991; Dr.-Ing.E.h., Hochschule f. Architektur und Ballwesen, Weimar, 1991; Dottore ad honorem in Matematica, University of Siena, Italy, 1992; Inländische Auszeichnungen/Ehrungen: Werner-von-Siemens-Ring, Stiftung Werner-von- Siemens-Ring, 1964; Dieselmedaille in Gold, DEV Deutscher Erfinder- Verband/Nurnberg, 1969; Grosses Verdienstkreuz des Verdienstordens der Bundesrepublik Deutschland, 1972,, mit Stern, 1985); Ehrenmitglied der Deutschen Akademie der Naturforscher LEOPOLDINA, Halle/Saale, 1972; Aachener und Munchener Preis, Carl-Arthur-Pastor- Stiftung, Kuratorium der Aachener und Munchener Versicherungs AG, 1980; Ehrenplakette der Stadt Bad Hersfeld, 1980; Konrad-Zuse-Medaille, ZDB/Zentralverband des Deut- schen Baugewerbes) 1983 Bernhard-Weiss-Plakette, VDMA/Verband Deutscher Maschinen- und Anlagenbau e.V./Dusseldorf, 1981; Bayerischer Maximiliansorden, Bayerischer Ministerprasident, 1984; Goldener Ehrenring, Deutsches Museum/Munchen, 1984; Cothenius-Medaille, LEOPOLDINA, Deutsche Akade- mie der Naturforscher/Halle – Saale, 1985 ; Ernst-Reuter-Plakette, Senat Berlin, 1985; VDE-Ehrenring, Verband Deutscher Elektrotechniker e.V./Dusseldorf, 1986; Philip-Morris-Ehrenpreis, Philip Morris GmbH/DABEI, 1987; Wilhelm-Leuschner-Medaille, Hessischer Ministerprasident, 1987; Ehrenmitglied: Deutsche Akademie der Naturforscher LEopollDINA, Halle/Saale, 1972; Akademischer Verein Motiv, 1982; Verein des Schleswig-Holsteinisches Museums fur Rechen- und Schreibtechnik e.V., Altzenholz, heute: MICOM, 1983; Gesellschaft fur Informatik e.V./GI 1986 Verein islandischer Ingenieure, Reykjavik/Island, 1985; Deutsches Museum, Munchen, 1990; Vereinigung der Freunde und Förderer der Ingenieur- schule an der Fachhochschule Schmalkalden e.V., 1992; Ehrenburaerrecht: Ehrenburgerrecht der Stadt Hunfeld, 1975; Namensqebunq: Konrad-Zuse-Strasse, in Bad Hersfeld/Hessen, 1972; Konrad-Zuse-Schule, in Hünfeld/Hessen, 1978; Konrad-Zuse-Medaille, ZDB Zentralverband des Deutschen Baugewerbes und GI/Gesellschaft f. lnformatik e.V., 1981; Konrad-Zuse-Zentrum für Informationstechnik Berlin/ZIB, in Berlin, 1984; Konrad-Zuse-Zertifikat, Freundeskreis der Berufl. Schulen e.V./Bad Hersfeld, 1985; Zuse-Raum, Berufliche Schulen/Bad Hersfeld, 1985; Konrad-Zuse-Gesellschaft, Grundung am 6. 9. 88 in Hünfeld, 1988; Konrad-Zuse-Haus, Fa. PDS Programm + Software GmbH, Rotenburg/Wumme, 1989; Konrad-Zuse-Programm, Förderung v. Gastdozenten ausländischer Hochschullehrer – DAAD/Deutscher Aka-demischer Austauschdienst, Bonn, 1991; Konrad-Zuse-Zimmer, Schelztor-Gymnasium, Esslingen, 1991; Zusestrasse, in 0-Hoyerswerda, 1991.

During 1936 to 1938 Konrad Zuse developed and built the first binary digital computer in the world (Zl). A copy of this computer is on display in the Museum for Transport and Technology (“Museum fur Verkehr und Technik”) (since 1989) in Berlin.

The first fully functional program-controlled electromechanical digital computer in the world (the Z3) was completed by Zuse in 1941, but was destroyed in 1944 during the war. Because of its historical importance, a copy was made in 1960 and put on display in the German Museum (“Deutsches Museum”) in Munich.

Next came the more sophisticated Z4, which was the only Zuse Z-machine to survive the war. The Z4 was almost complete when, due to continued air raids, it was moved from Berlin to Gottingen where it was installed in the laboratory of the Aerodynamische Versuchanstalt (DVL/Experimental Aerodynamics Institute). It was only there for a few weeks before Gottingen was in danger of being captured and the machine was once again moved to a small village “Hinterstein” in the Allgau/Bavaria. Finally it was taken to Switzerland where it was installed in the ETH (Federal Polytechnical Institute/”Eidgenossisch Technische Hochschule”) in Zurich in 1950. It was used in the Institute of Applied Mathematics at the ETH until 1955.

My first computer and first thoughts about data processing

[1]

I started in 1934, working independently and without knowledge of other developments going on around me. In fact, I hadn’t even heard of Charles Babbage when I embarked on my work. At that time, the computing industry was limited to mechanical calculators using the decimal system. Punched card devices were slightly further developed and able to deal with relatively complex operations for statistical and accounting purposes. However, these machines were almost entirely designed for commercial application. This meant that mathematicians and engineers had to develop computers on their own, working independently from one another. I was no exception.

At the beginning of the 30s, while studying civil engineering in Berlin, I decided to develop and build bigger calculating machines, more suitable for engineering purposes. I approached the problem from various angles:

Firstly, from a logical and mathematical point of view:

This involved
1. program control,
2. the binary system of numbers,

3. and floating point arithmetic.

Today, these concepts are taken for granted, but at the time this was new ground for the computing industry.

Secondly, from the design angle:
1. allowing fully automatic arithmetical calculation,
2. a high-capacity memory,

3. and modules or relays operating on the yes/no principle.

My research was initially aimed at pure number calculation, but soon led on (1935/36) to new ideas about “computing” in general. Personally, I believe that was the birth of modern computer science. I recognized that computing could be seen as a general means of dealing with data and that all data could be represented through bit patterns, generally speaking.

That led to my basic hypothesis that:

“data processing starts with the bit”

At that time, of course, I didn’t talk of “bits”, but of “yes/no status”. On the basis of this hypothesis I defined “computing” as

“the formation of new data from input according to a given set of rules”

This basic theory meant that all computing operations could be carried out by relays operating according to the dual status principle just mentioned. The most suitable devices available at the time were telephone relays.

Now a link with mathematical logic had been forged. As an engineer I had no idea of the existence of such a discipline. I developed a system of “conditional propositions” for relays – something that corresponded approximately to what is known as Boolean algebra today. My former mathematics teacher showed me that this sort of calculation was identical with the propositional calculus of mathematical logic.

From the engineering point of view, the gap between this and pure mathematical logic was bridged in order to simplify the design and programming of computing machines. At roughly the same time in England, the mathematician and logician Alan Turing was in the process of solving this problem from a different angle. He used a very simple computer as a model in order to place theoretical logic on a more formal basis. Turing’s work was of major importance for the theory of computer science. However, his ideas had little influence on the practical development of computing machines.

The theories needed to be put into practice. First of all high-capacity memories had to be designed. At that time, (1935), memory consisted of single registers operating a system of numbered wheels using the decimal system. Typical problems were the input and retrieval of information, as well as the choice of counters. Capacity was fairly restricted, although some punch card machines were able to deal with up to 20 counters. These machines generally functioned on the basis that a number could be “added on”.

But a new problem had to be overcome: pure memory was needed without the adding-on facility, but with high capacity and a special selection facility, as well as an elegant way of communicating with the periphery. I thought it was a good idea to base such a memory device on binary numbers from the outset. My idea was to divide the machine up into cells which would be able to hold data for a complete number, in other words, the operational sign, exponent and mantissa (where a floating point was being used), as well as additional specifications. Using the yes-no principle a “word” – as we would call it today – could be formed from a series of bits. The memory elements only needed to store yes-no values.

One device that could deal with this type of operation was the electro-magnetic relay, which can adopt two positions, “open” or “closed”. However, at the time I felt that the problem could be better solved mechanically. I played around with all sorts of levers, pins, steel plates, and so on, until I finally reached what was a very useful solution, for those days. My device consisted mainly of pins and steel plates, and in principle could be extended to 1,000 words. A proper machine using telephone relays would have needed 40,000 relays and filled a whole room.

The basic principle was that a small pin could be positioned right or left of a steel lug, thus memorizing the value 0 or 1. Input and retrieval were also effected via a steel-plate construction, and the individual parts could be stacked on top of one another in a system of layers. The address system also used binary code.[2] These machines had the advantage of being made almost entirely of steel, which made them suitable for mass production.

Individual memory elements could be easily arranged in matrix form, which was very useful as far as constructing computers was concerned. Not only was a number memory now available, but it could also be used to store general data drawn from practically any source. Logic studies conducted at the same time had already shown that general calculations with any sort of data structure were possible, and that this data could be made up entirely of bit combinations. That is why I had already called the storage system a “combination memory” in the patent application.

This was something new on the Babbage designs. It was clear that programs could be stored provided they were composed of bit combinations – one reason why programmable memory had already been patented by 1936.

In the course of pursuing the basic principles of mechanical memory I developed a mechanical relay technology. This I applied to both programming and calculating parts. At the time it was not clear whether all operations could be run according to the yes-no principle, or even whether that was a good idea. That was something that was only discovered later after much hard work. Initially I developed various adding machines for binary numbers which used elements providing up to three or four positions. This was done using both electro-magnetic and mechanical relays. Finally I found a solution which worked on the yes-no principle alone. By this time the similarities between essentially very different technologies were becoming increasingly obvious. I was faced with the choice of using either telephone relays or mechanical technology for my computing machine. As mechanical memory had proved successful (I was able to build a working model in six weeks), and because of the frightening number of relays needed in the alternative system, (around 1,000), I decided in favor of the mechanical version, at first.

Inventors are often faced with that sort of decision. Today, I know that opting for relays immediately would have been better. However, working on a completely private basis, with- just the help of some friends, I started to construct a mechanical model of the computer. At first I thought it would be possible to produce it quickly. In fact it took two years to set up a half-way functioning machine which I could present to the experts. Unfortunately the surviving photos are not very good and the machine itself proved somewhat unreliable! In fact, with the help of switching algebra, it proved easy to convert mechanical relay circuits for use in electro-magnetic relay technology.

At this point I would like to mention my friend Helmut Schreyer who was working on the development of electronic relays at that time. Helmut was a high-frequency engineer, and on completing his studies (around 1936) started working at Prof. Stäblein’s Institute at the Technical University in Berlin-Charlottenburg. Helmut, who was a close personal friend of mine, suddenly had the bright idea of using vacuum tubes. At first I thought it was one of his student pranks – he was always full of fun and given to fooling around. But after thinking about it we decided that his idea was definitely worth a try. Thanks to switching algebra, we had already married together mechanics and electro-magnetics – two basically different types of technology. Why, then, not with tubes? They could switch a million times faster than elements burdened with mechanical and inductive inertia.

The possibilities were staggering. But first basic circuits for the major logical operations such as conjunction, disjunction and negation had to be discovered. Tubes could not simply be connected in line like relay contacts. We agreed that Helmut should develop the circuits for these elementary operations first, while I dealt with the logical part of the circuitry. Our aim was to set up elementary circuits so that relay technology could be transferred to the tube system on a one-to-one basis. This meant the tube machine would not have to be redesigned from scratch. Schreyer solved this problem fairly quickly.

This left the way open for further development. We cautiously told some friends about the possibilities. The reaction was anything from extremely skeptical to spontaneously enthusiastic. Interestingly enough, most criticism came from Schreyer’s colleagues, who worked with tubes virtually all the time. They were doubtful that an apparatus with 2,000 tubes would work reliably. This critical attitude was the result of their own experience with large transmitters which contained several hundred tubes. Apart from that, conditions were not exactly propitious for the development of a fully tube-operated machine. The War had broken out in the interim, making the procurement of staff and material very difficult. Nothing could be done by private initiative. We therefore proposed the construction of a 2,000-tube computer for special use in anti-aircraft defense to the military authorities. Although the reaction was initially sympathetic towards the project we were asked simply, “How much time do you think you need for it?”. We replied, “Around two years. The response to this was, “And just how long do you think it’ll take us to win the war?”. The outcome was considerable obstruction and delay in the development of a German electronic computing machine. Schreyer was by now fully engaged in other projects. By the end of the War he had constructed a small experimental machine for 10 binary digits and around 100 tubes. But this machine was also lost in the general confusion just after the War.

After the War was finally over, news of the University of Pennsylvania ENIAC machine went all round the world – “18,000 tubes!”. We could only shake our heads. What on earth were all the tubes for? Schreyer and I parted company after the War. At that time it was prohibited to develop electronic equipment in West Germany. As Schreyer saw no means of continuing his very interesting research he emigrated to Brazil to take up a university chair.

Schreyer died in 1985.

The English development known as COLOSSUS was unheard of outside the circle of those working on it. It was only much later that the wraps came off this very interesting project. In 1980 Schreyer and I had the opportunity to speak to the COLOSSUS people in England. We compared our circuits and it turned out that there were considerable similarities. The English had also been working on logical operations and other similar design principles.

By the end of 1938 it seemed clear that electro-magnetic relays offered the best chance of producing a reliable operating computer quickly. Before I redesigned the Z1 to operate completely with relays I made a test with a small pilot machine, the Z2. I used the mechanical memory of the Z1 with a low storage capacity (16 words), as well as the card punch and reader to build a simple computer with 200 relays operating with 16 bits and on the basis of fixed- point arithmetic.

Young transmitter specialists, including Schreyer and other friends of mine, helped me design the circuits and choose the appropriate components. But although their advice was a great help, to a certain extent I expressly set out to explore new ground. The most important thing seemed to be to keep the frequency absolutely even, so that one cycle equaled one addition, itself comprising several steps. Frequency was set using rotating disks or rollers which were covered in alternating strips of conducting and non-conducting material, contact being made via carbon brushes This principle had many advantages. Tests could be run on the machine at any speed. Another advantage was that spark extinction took place at the brushes and not at the relay contacts when circuits were being shutdown. Despite well-meaning advice from some friends, I did not make use of certain well-known telephone communication tricks such as delayed-response relays.

All in all, I was able to gather enough experience with the Z2 in order to convert the complete Z1 design for relay operation. What emerged was the Z3, which is now considered to have been the first properly functioning computer in the world. In order to make fast progress the memory was also given a 64-word capacity, making use of relays.

The Z3′s basic specifications were:

• a binary number system
• floating point arithmetic
• 22-bit word length, with 1 bit for the sign, 7 exponential bits and a 14-bit mantissa
• 2,400 relays, 600 in the calculating and program section and 1,800 in the memory.

The calculations possible were addition, subtraction, multiplication, and division, taking the square root, as well as some ancillary functions. Construction of the machine was interrupted in 1939 when I was called up for military service. It was typical of the attitude prevalent in Germany at the time that I should be later released from active service, not to develop computers, but as an aircraft engineer. However, in my spare time, and with the help of friends, I was able to complete the machine. By 1941 it was working and I was able to show it to the aircraft construction authorities. The German Aircraft Research Institute in Berlin-Adlershof showed greatest interest. Professor Teichmann, who had been working on the problem of wing flutter, was particularly attracted. Unlike aircraft stress, wing flutter results in critical instability due to vibration of the wings, sometimes in conjunction with the tail unit. Complex calculations were needed in order to overcome this design problem. The most difficult part was calculating the so-called “Küssner determinants” based on complex numbers and unknown quantities in the main diagonal. I achieved a breakthrough using my equipment for this calculation. Unfortunately the Aircraft Research Institute had not been given a high enough priority for me to be released from military service. Only Professor Herbert Wagner, who was working on the development of remote-controlled flying bombs, and for whom I worked as a stress analyst, was in this enviable position. However, Wagner was very understanding, and helped as much as possible by allowing me to use some of my work time on the project. By then I had already set up my own small engineering business, the “Zuse-Ingenieur-Büro” in Berlin. The Z3 was later destroyed after bombing raids. Because of its historic importance we rebuilt it 20 years later; a replica now stands in the Deutsches Museum in Munich.

Around 1942 it was decided to build a more powerful, improved Z4. We thought that we would be able to have it ready within one, to one-and-a-half years. It was to have a mechanical memory with a capacity of 1,024 words, several card readers and punches, and various facilities to enable flexible programming (address translation, conditional branching).

Construction of the machine started well but it was not long before the War imposed its delays. In the end, construction was not completed until the close of the War. Procurement of staff and materials became increasingly difficult, and around 1943 the Berlin blitz began, with heavy bomber raids nearly every day. Several times we had to move location with the machine. During the last few weeks of the War we found refuge in Göttingen. The Z4 was the only model we were able to save, and this in the face of considerable difficulties. On the 28 April 1945 we were able to demonstrate the Z4 to Professors Prandtl, Betz and Küssner. But the Western and Eastern fronts were drawing closer daily and nobody could say whether Göttingen would be bombed or not, or whether the Z4 was safe there. The Ministry of Aviation ordered us to take the machine to the underground works in the Harz. It was there that we first learnt of the terrible conditions under which the so-called reprisal weapons – the V1 and V2 – were being built. We refused to leave the machine there, and, with the help of Wernher von Braun’s staff, we managed to get hold of a truck to transport it elsewhere. And so the Z4 odyssey continued. We then moved south, ending up in a small Alpine village called Hinterstein in the Allgäu, where we were finally able to find a good place to store the machine.

The Brits may have beaten the Americans, but it seems we were both pipped by the Germans. No, not football. Computers.

Colossus was not, in fact, the world’s first programmable computer: that particular distinction belongs to the Z3, built in 1941 by Konrad Zuse, a German civil engineer.

The Z3 was based on a binary floating-point number and switching system. It could perform between three and four additions per second, and could multiply in around five seconds. The program was fed in on a old movie film punched with holes, as paper was in short supply. It could perform basic arithmetic: addition, subtraction, multiplication and division and it could calculate square roots.

His early experiments building a mechanical computer were based on telephone relays: the most widely available and reliable ‘yes/no’ devices available to him at the time. Although he was aware of vacuum tubes, he opted to use relays in the Z3 because they were more reliable.

Zuse’s machine saw use during the war, but not as a codebreaker. Instead it was used to perform statistical analysis of the stresses on aircraft wings, and in particular, a problem known as wing-flutter. This vibration of an aircraft’s wing can cause a critical instability during flight. The calculations needed to overcome this design issue were incredibly complex, and it was this problem that the Z3 solved.

The Z3 was destroyed during bombing raids in the war, but Zuse managed to escape to Switzerland with its successor – the Z4 – which can now now be seen at the Deutsches Museum in Munich. ®

The First Freely Programmable Computer invented by Konrad Zuse

Konrad Zuse

Konrad Zuse (1910-1995) was a construction engineer for the Henschel Aircraft Company in Berlin, Germany at the beginning of WWII. Konrad Zuse earned the semiofficial title of “inventor of the modern computer” for his series of automatic calculators, which he invented to help him with his lengthy engineering calculations. Zuse has modestly dismissed the title while praising many of the inventions of his contemporaries and successors as being equally if not more important than his own.

One of the most difficult aspects of doing a large calculation with either a slide rule or a mechanical adding machine is keeping track of all intermediate results and using them, in their proper place, in later steps of the calculation. Konrad Zuse wanted to overcome that difficulty. He realized that an automatic-calculator device would require three basic elements: a control, a memory, and a calculator for the arithmetic.

Konrad Zuse's Z1 Circa 1938

In 1936, Zuse made a mechanical calculator called the Z1, the first binary computer. Zuse used it to explore several groundbreaking technologies in calculator development: floating-point arithmetic, high-capacity memory and modules or relays operating on the yes/no principle. Zuse’s ideas, not fully implemented in the Z1, succeeded more with each Z prototype.

In 1939, Zuse completed the Z2, the first fully functioning electro-mechanical computer.

Konrad Zuse completed the Z3 in 1941, with recycled materials donated by fellow university staff and students. This was the world’s first electronic, fully programmable digital computer based on a binary floating-point number and switching system. Zuse used old movie film to store his programs and data for the Z3, instead of using paper tape or punched cards. Paper was in short supply in Germany during the war.

According to “The Life and Work of Konrad Zuse” (by Horst Zuse)

In 1941, the Z3 contained almost all of the features of a modern computer as defined by John von Neumann and his colleagues in 1946. The only exception was the ability to store the program in the memory together with the data. Konrad Zuse did not implement this feature in the Z3, because his 64-word memory was too small to support this mode of operation. Due to the fact that he wanted to calculate thousands of instructions in a meaningful order, he only used the memory to store values or numbers.

The block structure of the Z3 is very similar to a modern computer. The Z3 consisted of separate units, such as a punch tape reader, control unit, floating-point arithmetic unit, and input/output devices.

Konrad Zuse wrote the first algorithmic programming language called ‘Plankalkül’ in 1946, which he used to program his computers. He wrote the world’s first chess-playing program using Plankalkül.

The Plankalkül language included arrays and records and used a style of assignment (storing the value of an expression in a variable) in which the new value appears in the right column. An array is a collection of identically typed data items distinguished by their indices (or “subscripts”), for example written something like A[i,j,k], where A is the array name and i, j and k are the indices. Arrays are best when accessed in an unpredictable order. This is in contrast to lists, which are best when accessed sequentially.

Zuse was unable to convince the Nazi government to support his work for a computer based on electronic valves. The Germans thought they were close to winning the War and felt no need to support further research.

The Z1 through Z3 models were destroyed during the war along with Zuse Apparatebau, the first computer company that Zuse formed in 1940. Zuse left for Zurich to finish his work on the Z4, smuggling the Z4 from Germany in a military truck, which he hid in stables on route to Zurich, Switzerland. He completed and installed the Z4 in the Applied Mathematics Division of Zurich’s Federal Polytechnical Institute, in use there until 1955. The Z4 had a mechanical memory with a capacity of 1,024 words and several card readers. Zuse no longer had to use movie film to store programs; he could now use punched cards. The Z4 had punches and various facilities to enable flexible programming including address translation and conditional branching. In 1949, he moved back to Germany to form a second company called Zuse KG for the construction and marketing of his designs. Zuse later rebuilt models of the Z3 in 1960 and the Z1 in 1984.