1902 Teleprinters

In 1902, a young electrical engineer called Frank Pearne approached Mr. Joy Morton, the president of the well-known Morton Salt Company. Pearne had been experimenting with printing telegraphs and needed a sponsor. Morton discussed the situation with his friend, the distinguished mechanical engineer Charles L. Krum, and they eventually decided they were interested in pursuing this project.
After a year of unsuccessful experiments, Pearne lost interest and wandered off into the sunset to become a teacher. Krum continued to investigate the problem and, in 1906, was joined by his son Howard, who had recently graduated as an electrical engineer. The mechanical and electrical talents of the Krums Senior and Junior complemented each other. After solving the problem of synchronizing the transmitter and receiver, they oversaw their first installation on postal lines between New York City and Boston in the summer of 1910.

These devices, called teleprinters, had a typewriter-style keyboard for entering outgoing messages and a roll of paper for printing incoming messages. The Krums continued to improve the reliability of their systems over the years. By 1914, teleprinters were being used by the Associated Press to deliver copy to newspaper offices throughout America, and by the early 1920s they were in general use around the world.

Meanwhile, toward the end of the 1920s and the early 1930s, scientists and engineers began to focus their attentions on the issue of computing. The first devices, such as Vannevar Bush's Differential Analyzer, were predominantly analog, but not everyone was a devotee of analog computing.
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1906 The vacuum Tube

Edison did not develop his light bulb vacuum tube findings any further, but an English physicist, John Ambrose Fleming, discovered that the Edison Effect could also be used to detect radio waves and to convert them to electricity. Fleming went on to develop a two-element vacuum tube known as diode

In 1906, the American inventor Lee de Forest introduced a third electrode called the grid into the vacuum tube. The resulting triode could be used as both an amplifier and a switch, and many of the early radio transmitters were built by de Forest using these triodes (he also presented the first live opera broadcast and the first news report on radio).
De Forest's triodes revolutionized the field of broadcasting and were destined to do much more, because their ability to act as switches was to have a tremendous impact on digital computing.
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1918 The Enigma machine

Enigma was an electro-mechanical device that utilised a series of three (and then four) stepping wheels in a system to 'scramble' a plain text message to produce cipher text via polyalphabetic substitution.
The number of cipher text alphabets is enormous, leading Germany's military authorities to believe, wrongly as it turned out, in the absolute security of this cipher system.
Although this machine had been available since the 1918, and exhibited in 1920, it was only seen as a usable coding machine by the Polish and German armies.
At this exhibition the British secret service also purchased an Enigma machine to evaluate but thought it too complicated. This machine lay undetected in a basement at MI5 HQ all through the Second World War. Had it been found many more lives may have been saved through its use. A good source of information can be found here>>  here>> and here>>
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1920 Arrays

John Logie Baird in England and Clarence Hansell in the US patent the idea of using ARRAYS of hollow pipes or transparent rods to transmit images - basic fibre optics.
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1926 The Transistor Pt1

The transistor and subsequently the integrated circuit must certainly qualify as two of the greatest inventions of the twentieth century. These devices are formed from materials known as semiconductors, whose properties were not well-understood until the 1950s. However, as far back as 1926, Dr. Julius Edgar Lilienfield from New York filed for a patent on what we would now recognize as an NPN junction transistor being used in the role of an amplifier (the patent title was "Method and apparatus for controlling electric currents" More here>>
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1931 The electric logic machine

In 1936, the American psychologist Benjamin Burack from Chicago constructed what was probably the world's first electrical logic machine. Burack's device used light bulbs to display the logical relationships between a collection of switches, but for some reason he didn't publish anything about his work until 1949.
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1937 First electric computer

John Vincent Atanasoff conceived basic design principles for the first electronic-digital computer in the winter of 1937 and, assisted by his graduate student, Clifford E. Berry, constructed a prototype in October 1939. It used binary numbers, direct logic for calculation, and a regenerative memory. It embodied concepts that would be central to the future development of computers.
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.  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 (aka ABC). 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 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.

1937 Turing Machine

1937 Zuse's Z1

Zuse's Z1 The first known working binary digital computer was called the ZI and was built by Konrad Zuse. It had a mechanical memory system.
A prototype with electromagnetic relays called the Z2 was built a year later, with storage capacity for 16 words, plus card punch and reader 1/0. It had 200 relays and operated with 16-bit integer arithmetic. The idea was to use this basic design in a bigger system like the ZI. The result was the Z3, which had a 64-word capacity, floating point arithmetic,22-bit word length and 2,400 relays.

Of these, 600 were for calculations and 1,800 for memory. Although based on relays, the Z3 was very sophisticated for its time; for example, it utilized the binary number system and could handle floating-point arithmetic. (Zuse had considered employing vacuum tubes, but he decided to use relays because they were more readily available, and also because he feared that tubes were somewhat unreliable).
Construction was interrupted in 1939 when Zuse was called up for military service, so the, Z3 wasn't completed until 1941. The Z3 was the first fully functioning, program-controlled electromechanical digital computer.

The first three Z computers were destroyed during the war (although a new Z3 was reconstructed in the 1960s). Zuse started work on a general-purpose relay computer called the Z4. this did survive the bombing (in a cave in the Bavarian Alps) and by 1950 it was up and running in a Zurich bank. The Z4 was started in 1942 and was intended to have a storage capacity of 1,024 words.

It is interesting to note that paper was in short supply in Germany during to the war, so instead of using paper tape or punched cards, Zuse was obliged to punch holes in old movie film to store his programs and data. We may only speculate as to the films Zuse used for his hole-punching activities; for example, were any first-edition Marlene Dietrich classics on the list? (Marlene Dietrich fell out of favor with the Hitler regime when she emigrated to America in the early 1930s, but copies of her films would still have been around during the war.)

Zuse was an amazing man, who, in many respects, was well ahead of his time. For example, in 1958 he proposed a parallel processor called a field computer, years before parallel computing became well understood. He also wrote (but never implemented) Pkankalkül, which is a strong contender as the first high-level programming language.

To fully appreciate Zuse's achievements, it is necessary to understand that his background was in construction engineering. Also, Zuse was completely unaware of any computer-related developments in Germany or in other countries until a very late stage. In 1957, Zuse received the honorary degree of Dr.techn. in Berlin, and he was subsequently showered with many other honors and awards. There is an excellent site here>> with a biography and an image gallery of the various machines.
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1940 Claud Shannon   The connection between Boolean algebra and circuits based on switches had been recognized as early as 1886 by an educator called Charles Pierce, but nothing substantial happened in this area until Claude E. Shannon published his 1938 paper.
Following Shannon's paper, a substantial amount of attention was focused on developing electronic logic machines. Unfortunately, interest in special-purpose logic machines waned in the 1940s with the advent of general-purpose computers, which proved to be much more powerful and for which programs could be written to handle formal logic.
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1940 Teleprinters to modems

At a meeting in New Hampshire in September 1940 George Robert Stibitz used a digital machine to perform the first demonstration of remote computing. Leaving his computer in New York City, he took a teleprinter to the meeting which he connected to the computer using a telephone line. Stibitz then proceeded to astound the attendees by allowing them to pose problems which were entered on the teleprinter; within a minute, the teleprinter printed the answers generated by the computer.
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1941 Tom Flowers

The design for the theoretical Turing Machine (later Colossus) was invented and built by a post office engineer called Tom Flowers.

Flowers was a Londoner with a passion for electronics. Having gained his degree in electronic engineering he went to work for the Post Office. His dream was to try to convert Britain's mechanical telephone system into an electronic one, but opinion was against him. During the Second World War he was drafted into Bletchley Park to join the ranks of mathematicians and cryptographers who were trying to crack Germany's code system. When he saw the project for Turing's machine from Professor Max Newman (one of Turing's old tutors at Cambridge) he felt that the overall machine was similar to an automatic telephone exchange system.
The need now became an urgency for a machine  powerful enough to break the Lorenz code created by the German Geheimfernschreiber (secret telegraph), which was far stronger than ENIGMA and indeed was the code used by Adolph Hitler himself for his secret transmissions.

Tom Flowers felt that what was needed for this machine was a massive collection of switches just like his ideas for the new automatic telephone exchange. The current problem of running two teleprinter tapes in line fully synchronised with each other had not been solved. The tapes kept running out of step with each other. What was needed was a faster system that memorised one side of the stream making side by side synchronising a thing of the past.
To do this he was to use over 1800 valves instead of mechanical switches. Valves were not seen to be reliable enough however Flowers suggested that valves were fine if never switched off and had proved this with the post office exchanges.
Due to the war offices belief in the unreliability of valves and the time it would take to build they dismissed the idea.
Flowers decided however to build one himself using at the GPO research facility at Dolly's hill. Using his own money and working around the clock he designed and built it in only 10 months. This machine was called Colossus (because it was colossal filling a whole room). The Colossus Mark I was one of the world's earliest (if not the first) working programmable electronic digital computer and could crack the most comprehensive German code within hours giving the allies a huge advantage. The war office immediately ordered 10 machines even after their initial cynicism.

After the war Tommy returned to the GPO and tried to convince his superiors of the use of computers. The were unaware that he had built one already because of the official secrets act. They were unconvinced and Britain again lost out to the Americans on the computer revolution.

Without doubt it was Tommy Flowers who turned the genius of Alan Turin's ideas into a real working computer that turned the tide of world events at the time and started the revolution of the electronic computer. Tommy Flowers died on 28 October 1998, aged 92.

1943 Colossus

The Colossus Mark I consisted of 1,800 vacuum tubes (valves), and was soon superseded by (and upgraded to) the Mark 2. Due to the 1800 valves Colossus was huge and filled a whole room. It could read data at 5,000 characters per second and could perform up to 100 Boolean operations simultaneously through each of its five tape channels across a five-character matrix, in 200 microseconds. Although it's hard to equate this with today's calculating power, Colossus' extreme specialisation makes it fast at breaking codes even compared to today's computers. It was calculated that the war was shortened by a whole year and countless lives saved. In D-Day alone the awareness of two Panzer divisions on a proposed landing site saved many lives. At the end of the war all but two of the Colossus machines (they were used by GCHQ to spy on de-code Russian information and at least one may still be intact)  were dismantled however  In 1996, a Colossus was rebuild and went on show at Bletchley Park museum.
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1945 ENIAC

Considered by some to be the first electronic digital computer, this massive American machine with 18,000 tubes was predated by both Colossus and Konrad Zuse's first four Z systems. The American military were pushing for a machine that would calculate ballistics and therefore were providing substantial funding.
ENIAC was the prototype from which most other modern computers evolved. It embodied almost all the components  and concepts of today's high- speed, electronic digital computers. Its designers conceived what has now become standard circuitry such as the gate (logical "and" element), buffer (logical "or" element) and used a modified Eccles-Jordan flip-flop as a logical, high-speed storage-and-control device. The machine's counters and accumulators, with more sophisticated innovations, were made up of combinations of these basic elements.
ENIAC could discriminate the sign of a number, compare quantities for equality, add, subtract, multiply, divide, and extract square roots. ENIAC stored a maximum of twenty 10-digit decimal numbers. Its accumulators combined the functions of an adding machine and storage unit. No central memory unit existed, per se. Storage was localized within the functioning units of the computer.
The primary aim of the designers was to achieve speed by making ENIAC as all-electronic as possible. The only mechanical elements in the final product were actually external to the calculator itself. These were an IBM card reader for input, a card punch for output, and the 1,500 associated relays. More information can be found here>>
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1948 Cybernetics

Cybernetics is the fancy name for systems theory, which studies the way feedback loops work. It was invented during the 1940s at the Massachusetts Institute of Technology and paved the way for automation and computing. A multidisciplinary team including Norbert Wiener (mathematician), Warren McCulloch (neurophysiologist) and Jay Forrester (electronics engineer) modelled theories of how living organisms worked on self-regulating mechanical processes, and vice versa. Wiener's Cybernetics, or Control and Communication in the Animal and the Machine, and The Mathematical Theory of Communication by Claude Shannon and Warren Weaver, both published in 1948, marked the arrival of a new epoch. The latter founded info!mation theory.
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In 1948 The Transistor Pt22

Bell Laboratories in the United States began research into semiconductors in 1945, and physicists William Shockley, Walter Brattain and John Bardeen succeeded in creating the first point- contact germanium transistor on the 23rd December, 1947 (they took a break for the Christmas holidays before publishing their achievement, which is why some reference books state that the first transistor was created in 1948). More here>>

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1949 EDSAC

Maurice Wilkes assembled the EDSAC, the first practical stored-program computer, at Cambridge University. His ideas grew out of the Moore School lectures he had attended three years earlier. EDSAC contained 3,000 vacuum tubes and used mercury delay lines for memory.
For programming the EDSAC, Wilkes established a library of short programs called subroutines stored on punched paper tapes. Output results were passed to a tele-printer. Additionally, EDSAC is credited as using one of the first assemblers called "Initial Orders," which allowed it to be programmed symbolically instead of using machine code. An article on Maurice Wilkes reproduced from the excellent Personal Computer World can be found here>>
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1949 Joseph Lyons start development of "LEO"

In October 1947, the directors of J. Lyons & Company, a British catering company famous for its teashops but with strong interests in new office management techniques, decided to take an active role in promoting the commercial development of computers .
See also this excellent web page on the development of LEO>> and an excellent timeline here>>
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1950 Bipolar Transistor

By the late 1950s, bipolar transistors were being manufactured out of silicon rather than germanium (although germanium had certain electrical advantages, silicon was cheaper and easier to work with). Bipolar junction transistors are formed from the junction of three pieces of doped silicon called the collector base, and emitter. The original bipolar transistors were manufactured using the mesa process, in which a doped piece of silicon called the mesa (or base) was mounted on top of a larger piece of silicon forming the collector, while the emitter was created from a smaller piece of silicon embedded in the base.
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1950 The first digital modem

Digital modems developed from the need to transmit data for North American air defence during the 1950s. Modems were used to communicate data over the public switched telephone network or PSTN. Analogue telephone circuits can only transmit signals that are within the frequency range of voice communication. A modem sends and receives data between two computers. Modem stands for modulate/demodulate.
See also the Modem tutorial for all you need to know about modems here>>.
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1951 LEO becomes operational

In 1951 the "LEO I" computer was operational and ran the orld's first regular routine office computer job.The company LEO Computers Ltd was formed in 1954.
LEO II computers were installed in many British offices, including Ford Motor Company, British Oxygen Company and the 'clerical factory' of the Ministry of Pensions at Newcastle. LEO lll computers were installed in Customs & Excise, Inland Revenue, The Post Office and in Australia, South Africa and Czechoslovakia.

LEO Computers Ltd merged with the computer interests of English Electric in 1963 to form English Electric LEO, and later, English Electric Leo Marconi (EELM). Subsequent mergers eventually found LEO incorporated into ICL in 1968, whilst the Bureau operation, based at Hartree House, combined with Barclays to form Baric.
See also this excellent web page on the development of LEO>> and an excellent timeline here>>
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1956 IBM RAMAC

The era of magnetic disk storage dawned with IBM's shipment of a 305 RAMAC to Zellerbach Paper in San Francisco. The IBM 350 disk file served as the storage component for the Random Access Method of Accounting and Control. It consisted of 50 magnetically coated metal platters with 5 million bytes of data. The platters, stacked one on top of the other, rotated with a common drive shaft.
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1959 The Integrated Circuit

The invention of the IC (Integrated Circuit) was central to the industry as we know it. In the late 1950s, electrical engineers were confounded by a problem they called the Tyranny of Numbers. This grandiose title referred to the problem of manufacturing the constituent electrical parts to make increasing complex circuits from discrete components. The problem was that as the design for circuits improved, the number of components required grew exponentially, far in excess of the number that could actually be physically assembled together. The solution to this came from two men. John Kilby was working at Texas Instruments and Robert Noyce at Fairchild Semiconductors. Their answer was to fabricate complete networks of components on to a single crystal of semiconductor material. This breakthrough, named the monolithic integrated circuit, enabled devices to be made much smaller, more complex and considerably faster, and is credited as being the discovery that kicked off the computer revolution of the late 20th century. In fact, Robert Royce went on to be one of the key instigators of this revolution as co-founder of chip giant Intel.
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