Replica of the Atanasoff–Berry computer at Iowa State UniversityThe 1946 ENIAC computer used more than 17,000 vacuum tubes
A vacuum-tube computer, now termed a first-generation computer, is a computer that uses vacuum tubes for logic circuitry. While the history of mechanical aids to computation goes back centuries, if not millennia, the history of vacuum tube computers is confined to the middle of the 20th century. Lee De Forest invented the triode in 1906. The first example of using vacuum tubes for computation, the Atanasoff–Berry computer, was demonstrated in 1939. Vacuum-tube computers were initially one-of-a-kind designs, but commercial models were introduced in the 1950s and sold in volumes ranging from single digits to thousands of units. By the early 1960s vacuum tube computers were obsolete, superseded by second-generationtransistorized computers.
Much of what we now consider part of digital computing evolved during the vacuum tube era. Initially, vacuum tube computers performed the same operations as earlier mechanical computers, only at much higher speeds. Gears and mechanical relays operate in milliseconds, whereas vacuum tubes can switch in microseconds. The first departure from what was possible prior to vacuum tubes was the incorporation of large memories that could store thousands of bits of data and randomly access them at high speeds. That, in turn, allowed the storage of machine instructions in the same memory as data—the stored program concept, a breakthrough which today is a hallmark of digital computers.
Other innovations included the use of magnetic tape to store large volumes of data in compact form (UNIVAC I) and the introduction of random access secondary storage (IBM RAMAC 305), the direct ancestor of all the hard disk drives we use today. Even computer graphics began during the vacuum tube era with the IBM 740 CRT Data Recorder and the Whirlwind light pen. Programming languages originated in the vacuum tube era, including some still used today such as Fortran & Lisp (IBM 704), Algol (Z22) and COBOL. Operating systems, such as the GM-NAA I/O, also were born in this era.
Development
The use of cross-coupled vacuum-tube amplifiers to produce a train of pulses was described by Eccles and Jordan in 1918. This circuit became the basis of the flip-flop, a circuit with two states that became the fundamental element of electronic binary digital computers.
The Atanasoff–Berry computer, a prototype of which was first demonstrated in 1939, is now credited as the first vacuum-tube computer.[1] However, it was not a general-purpose computer, being able to only solve a system of linear equations, and was also not very reliable.
The Colossus computer at Bletchley Park
During World War II, special-purpose vacuum-tube digital computers such as Colossus were used to break German machine (teleprinter) ciphers known as Fish. The military intelligence gathered by these systems was essential to the Allied war effort. By the end of the war 10 Mark II COLOSSI were in use at Bletchley Park; they superseded the Heath Robinson. Each COLOSSI used 1,600 vacuum tubes (Mark I) and 2,400 vacuum tubes (Mark II).[1] The wartime codebreaking at BP was kept secret until the 1970s.[1]
Also during the war, electro-mechanical binary computers were being developed by Konrad Zuse. The German military establishment during the war did not prioritize computer development. An experimental electronic computer circuit with around 100 tubes was developed in 1942, but destroyed in an air raid.
In the United States, work started on the ENIAC computer late in the Second World War. The machine was completed in 1945. Although one application which motivated its development was the production of firing tables for artillery, one of the first uses of ENIAC was to carry out calculations related to the development of a hydrogen bomb. ENIAC was initially programmed with plugboards and switches instead of an electronically stored program. A post-war series of lectures disclosing the design of ENIAC, and a report by John von Neumann on a foreseeable successor to ENIAC, First Draft of a Report on the EDVAC, were widely distributed and were influential in the design of post-war vacuum-tube computers.
Early machines used to tabulate punch cards could only add and subtract. In 1931 IBM introduced an electromechanical multiplying punch, the IBM 601. After World War II, IBM made a version, the 603, that used vacuum tubes to perform the calculations.[2] Surprised by market demand for it, it introduced, in 1948, a more compact version the IBM 604, using 1250 miniature vacuum tubes in removable plug-in modules. Much faster than the 601, it could divide and perform up to 60 program steps in one card cycle. Some 5400 units were leased or sold, making it the first successful commercial application of electronic computation.
The Ferranti Mark 1 (1951) is considered the first commercial stored program vacuum tube computer. The first mass-produced computers were the Bull Gamma 3 (1952, 1,200 units) and the IBM 650 (1954, 2,000 units).
Design
Vacuum-tube technology required a great deal of electricity. The ENIAC computer (1946) had over 17,000 tubes and suffered a tube failure (which would take 15minutes to locate) on average every two days. In operation the ENIAC consumed 150kilowatts of power,[3] of which 80kilowatts were used for heating tubes, 45kilowatts for DC power supplies, 20kilowatts for ventilation blowers, and 5kilowatts for punched-card auxiliary equipment.
An IBM 650 at Texas A&M University
Because the failure of any one of the thousands of tubes in a computer could result in errors, tube reliability was of high importance. Special quality tubes were built for computer service, with higher standards of materials, inspection and testing than standard receiving tubes.
One effect of digital operation that rarely appeared in analog circuits was cathode poisoning. Vacuum tubes that operated for extended intervals with no plate current would develop a high-resistivity layer on the cathodes, reducing the gain of the tube. Specially selected materials were required for computer tubes to prevent this effect. To avoid mechanical stresses associated with warming the tubes to operating temperature, often the tube heaters had their full operating voltage applied slowly, over a minute or more, to prevent stress-related fractures of the cathode heaters. Heater power could be left on during standby time for the machine, with high-voltage plate supplies switched off. Marginal testing was built into sub-systems of a vacuum-tube computer; by lowering plate or heater voltages and testing for proper operation, components at risk of early failure could be detected. To regulate all the power-supply voltages and prevent surges and dips from the power grid from affecting computer operation, power was derived from a motor-generator set that improved the stability and regulation of power-supply voltages.[citation needed]
Two broad types of logic circuits were used in construction of vacuum-tube computers. The "asynchronous", or direct, DC-coupled type used only resistors to connect between logic gates and within the gates themselves. Logic levels were represented by two widely separated voltages. In the "synchronous", or "dynamic pulse", type of logic, every stage was coupled by pulse networks such as transformers or capacitors. Each logic element had a "clock" pulse applied. Logic states were represented by the presence or absence of pulses during each clock interval. Asynchronous designs potentially could operate faster, but required more circuitry to protect against logic "races", as different logic paths would have different propagation time from input to stable output. Synchronous systems avoided this problem, but needed extra circuitry to distribute a clock signal, which might have several phases for each stage of the machine. Direct-coupled logic stages were somewhat sensitive to drift in component values or small leakage currents, but the binary nature of operation gave circuits considerable margin against malfunction due to drift.[4] An example of a "pulse" (synchronous) computer was the MIT Whirlwind. The IAS computers (ILLIAC and others) used asynchronous, direct-coupled logic stages.
Tube computers primarily used triodes and pentodes as switching and amplifying elements. At least one specially designed gating tube had two control grids with similar characteristics, which allowed it to directly implement a two-input AND gate.[4]Thyratrons were sometimes used, such as for driving I/O devices or to simplify design of latches and holding registers. Often vacuum-tube computers made extensive use of solid-state ("crystal") diodes to perform AND and OR logic functions, and only used vacuum tubes to amplify signals between stages or to construct elements such as flip-flops, counters, and registers. The solid-state diodes reduced the size and power consumption of the overall machine.
Memory technology
Early systems used a variety of memory technologies prior to finally settling on magnetic-core memory. The Atanasoff–Berry computer of 1942 stored numerical values as binary numbers in a revolving mechanical drum, with a special circuit to refresh this "dynamic" memory on every revolution. The war-time ENIAC could store 20 numbers, but the vacuum-tube registers used were too expensive to build to store more than a few numbers. A stored-program computer was out of reach until an economical form of memory could be developed.
In 1944, J. Presper Eckert proposed using mercury delay-line memory in a successor to the ENIAC which would become the EDVAC. Eckert had earlier worked with delay line memory for radar signal processing. Maurice Wilkes built EDSAC in 1947, which had a mercury delay-line memory that could store 32words of 17bits each. Since the delay-line memory was inherently serially organized, the machine logic was also bit-serial as well.[5] Eckert and John Mauchly used the technology in the 1951 UNIVAC I and received a patent for delay-line memory in 1953. Bits in a delay line are stored as sound waves in the medium, which travel at a constant rate. The UNIVACI (1951) used seven memory units, each containing 18 columns of mercury, storing 120bits each. This provided a memory of 1,000 12-character words with an average access time of 300microseconds.[6] This memory subsystem formed its own walk-in room.
Williams tubes were the first true random-access memory device. The Williams tube displays a grid of dots on a cathode-ray tube (CRT), creating a small charge of static electricity over each dot. The charge at the location of each of the dots is read by a thin metal sheet just in front of the display. Frederic Calland Williams and Tom Kilburn applied for patents for the Williams tube in 1946. The Williams tube was much faster than the delay line, but suffered from reliability problems. The UNIVAC 1103 used 36 Williams tubes with a capacity of 1,024bits each, giving a total random access memory of 1,024words of 36bits each. The access time for Williams-tube memory on the IBM 701 was 30microseconds.[6]
Magnetic drum memory was invented in 1932 by Gustav Tauschek in Austria.[7][8] A drum consisted of a large rapidly rotating metal cylinder coated with a ferromagnetic recording material. Most drums had one or more rows of fixed read-write heads along the long axis of the drum for each track. The drum controller selected the proper head and waited for the data to appear under it as the drum turned. The IBM650 had a drum memory of 1,000 to 4,000 10-digit words with an average access time of 2.5milliseconds.
Core memory from Project Whirlwind, circa 1951
Magnetic-core memory was patented by A Wang in 1951. Core uses tiny magnetic ring cores, through which wires are threaded to write and read information. Each core represents one bit of information. The cores can be magnetized in two different ways (clockwise or counterclockwise), and the bit stored in a core is zero or one depending on that core's magnetization direction. The wires allow an individual core to be set to either a one or a zero and for its magnetization to be changed by sending appropriate electric current pulses through selected wires. Core memory offered random access and greater speed, in addition to much higher reliability. It was quickly put to use in computers such as the MIT/IBM Whirlwind, where an initial 1,024 16-bit words of memory were installed replacing Williams tubes. Likewise the UNIVAC 1103 was upgraded to the 1103A in 1956, with core memory replacing Williams tubes. The core memory used on the 1103 had an access time of 10microseconds.[6]
Start of the computer industry
The 1950s saw the evolution of the electronic computer from a research project to a commercial product, with common designs and multiple copies made,[9] thereby starting a major new industry. The early commercial machines used vacuum tubes and a variety of memory technologies, converging on magnetic core by the end of the decade.
Many of the early commercial machines carried on from the one-off machines and were designed for rapid mathematical calculations needed for scientific, engineering and military purposes. But some were designed for data-processing workloads generated by the large, existing punch card ecosystem. IBM in particular divided its computers into scientific and commercial lines, which shared electronic technology and peripherals but had completely incompatible instruction set architectures and software. This practice continued into its second-generation (transistorized) machines, until reunification by the IBM System/360 project. SeeIBM 700/7000 series
Below is a list of these first generation commercial computers.
Built by IBM, also known as the Defense Calculator, based on the IAS computer, with Williams tube memory. The head of IBM famously expected to sell 5 units, but got orders for 18 on the first sales trip.[10] First machine in the IBM 700/7000 series.
Made by Compagnie des Machines Bull, one of the first mass-produced electronic digital computers. Initially designed to supplement punched card machines.[11][12]
A small computer for scientific and industrial purposes by the Bendix Corporation. It had a total of about 450 tubes (mostly dual triodes) and 300 germanium diodes.
The history of computing hardware covers the developments from early simple devices to aid calculation to modern day computers.
EDVAC was one of the earliest electronic computers. It was built by Moore School of Electrical Engineering, Pennsylvania. Along with ORDVAC, it was a successor to the ENIAC. Unlike ENIAC, it was binary rather than decimal, and was designed to be a stored-program computer.
BINAC is an early electronic computer that was designed for Northrop Aircraft Company by the Eckert–Mauchly Computer Corporation (EMCC) in 1949. Eckert and Mauchly had started the design of EDVAC at the University of Pennsylvania, but chose to leave and start EMCC, the first computer company. BINAC was their first product, the first stored-program computer in the United States; BINAC is also sometimes claimed to be the world's first commercial digital computer even though it was limited in scope and never fully functional after delivery.
Whirlwind I was a Cold War-era vacuum tube computer developed by the MIT Servomechanisms Laboratory for the U.S. Navy. Operational in 1951, it was among the first digital electronic computers that operated in real-time for output, and the first that was not simply an electronic replacement of older mechanical systems.
Magnetic-core memory is a form of random-access computer memory. It predominated for roughly 20 years between 1955 and 1975, and is often just called core memory, or, informally, core.
The UNIVAC I was the first general-purpose electronic digital computer design for business application produced in the United States. It was designed principally by J. Presper Eckert and John Mauchly, the inventors of the ENIAC. Design work was started by their company, Eckert–Mauchly Computer Corporation (EMCC), and was completed after the company had been acquired by Remington Rand. In the years before successor models of the UNIVAC I appeared, the machine was simply known as "the UNIVAC".
The IBM 650 Magnetic Drum Data-Processing Machine is an early digital computer produced by IBM in the mid-1950s. It was the first mass-produced computer in the world. Almost 2,000 systems were produced, the last in 1962, and it was the first computer to make a meaningful profit. The first one was installed in late 1954 and it was the most popular computer of the 1950s.
UNIVAC was a line of electronic digital stored-program computers starting with the products of the Eckert–Mauchly Computer Corporation. Later the name was applied to a division of the Remington Rand company and successor organizations.
The ERA 1101, later renamed UNIVAC 1101, was a computer system designed and built by Engineering Research Associates (ERA) in the early 1950s and continued to be sold by the Remington Rand corporation after that company later purchased ERA. Its (initial) military model, the ERA Atlas, was the first stored-program computer that was moved from its site of manufacture and successfully installed at a distant site. Remington Rand used the 1101's architecture as the basis for a series of machines into the 1960s.
The IBM 701 Electronic Data Processing Machine, known as the Defense Calculator while in development, was IBM’s first commercial scientific computer and its first series production mainframe computer, which was announced to the public on May 21, 1952. It was designed and developed by Jerrier Haddad and Nathaniel Rochester and was based on the IAS machine at Princeton.
The UNIVAC 1103 or ERA 1103, a successor to the UNIVAC 1101, was a computer system designed by Engineering Research Associates and built by the Remington Rand corporation in October 1953. It was the first computer for which Seymour Cray was credited with design work.
The IBM 700/7000 series is a series of large-scale (mainframe) computer systems that were made by IBM through the 1950s and early 1960s. The series includes several different, incompatible processor architectures. The 700s use vacuum-tube logic and were made obsolete by the introduction of the transistorized 7000s. The 7000s, in turn, were eventually replaced with System/360, which was announced in 1964. However the 360/65, the first 360 powerful enough to replace 7000s, did not become available until November 1965. Early problems with OS/360 and the high cost of converting software kept many 7000s in service for years afterward.
The UNIVAC Solid State was a magnetic drum-based solid-state computer announced by Sperry Rand in December 1958 as a response to the IBM 650. It was one of the first computers offered for sale to be (nearly) entirely solid-state, using 700 transistors, and 3000 magnetic amplifiers (FERRACTOR) for primary logic, and 20 vacuum tubes largely for power control. It came in two versions, the Solid State 80 and the Solid State 90. In addition to the "80/90" designation, there were two variants of the Solid State – the SS I 80/90 and the SS II 80/90. The SS II series included two enhancements – the addition of 1,280 words of core memory and support for magnetic tape drives. The SS I had only the standard 5,000-word drum memory described in this article and no tape drives.
The UNIVAC LARC, short for the Livermore Advanced Research Computer, is a mainframe computer designed to a requirement published by Edward Teller in order to run hydrodynamic simulations for nuclear weapon design. It was one of the earliest supercomputers.
The First Draft of a Report on the EDVAC is an incomplete 101-page document written by John von Neumann and distributed on June 30, 1945 by Herman Goldstine, security officer on the classified ENIAC project. It contains the first published description of the logical design of a computer using the stored-program concept, which has come to be known as the von Neumann architecture; the name has become controversial due to von Neumann's failure to name other contributors.
The UNIVAC II computer was an improvement to the UNIVAC I that the UNIVAC division of Sperry Rand first delivered in 1958. The improvements included the expansion of core memory from 2,000 to 10,000 words; UNISERVO II tape drives, which could use either the old UNIVAC I metal tapes or the new PET tapes; and some transistorized circuits. It was fully compatible with existing UNIVAC I programs for both code and data. It weighed about 16,000 pounds.
SEAC was a first-generation electronic computer, built in 1950 by the U.S. National Bureau of Standards (NBS) and was initially called the National Bureau of Standards Interim Computer, because it was a small-scale computer designed to be built quickly and put into operation while the NBS waited for more powerful computers to be completed. The team that developed SEAC was organized by Samuel N. Alexander. SEAC was demonstrated in April 1950 and was dedicated in June 1950; it is claimed to be the first fully operational stored-program electronic computer in the US.
The IBM 702 was an early generation tube-based digital computer produced by IBM in the early to mid-1950s. It was the company's response to Remington Rand's UNIVAC, which was the first mainframe computer to use magnetic tapes. As these machines were aimed at the business market, they lacked the leading-edge computational power of the IBM 701 and ERA 1103, which were favored for scientific computing, weather forecasting, the aircraft industry, and the military and intelligence communities.
The IBM Naval Ordnance Research Calculator (NORC) was a one-of-a-kind first-generation computer built by IBM for the United States Navy's Bureau of Ordnance. It went into service in December 1954 and was likely the most powerful computer at the time. The Naval Ordnance Research Calculator (NORC), was built at the Watson Scientific Computing Laboratory under the direction of Wallace Eckert.
Philco was one of the pioneers of transistorized computers. After the company developed the surface barrier transistor, which was much faster than previous point-contact types, it was awarded contracts for military and government computers. Commercialized derivatives of some of these designs became successful business and scientific computers. The TRANSAC Model S-1000 was released as a scientific computer. The TRANSAC S-2000 mainframe computer system was first produced in 1958, and a family of compatible machines, with increasing performance, was released over the next several years.
1 2 Edward L. Braun, Digital Computer Design: Logic, Circuitry, and Synthesis. Academic Press, 2014, ISBN1483275736, pp.116–126.
↑ Mark Donald Hill, Norman Paul Jouppi, Gurindar Sohi (ed.), Readings in Computer Architecture, Gulf Professional Publishing, 2000, ISBN1558605398, pages3–4.
↑ US Patent 2,080,100. Gustav Tauschek, Priority date August 2, 1932, subsequent filed as German Patent DE643803, "Elektromagnetischer Speicher für Zahlen und andere Angaben, besonders für Buchführungseinrichtungen" (Electromagnetic memory for numbers and other information, especially for accounting institutions).
↑ Universität Klagenfurt (ed.). "Magnetic drum". Virtual Exhibitions in Informatics. Retrieved 2011-08-21.
↑ "Monthly Computer Census". Computers and Automation. April 1962.
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