The Manchester Baby, also known as the Small-Scale Experimental Machine (SSEM),was the world's first electronic stored-program computer. It was built at the Victoria University of Manchester, England, by Frederic C. Williams, Tom Kilburn, and Geoff Tootill, and ran its first program on 21 June 1948.
A stored-program computer is a computer that stores program instructions in electronic memory. This contrasts with machines where the program instructions are stored on plugboards or similar mechanisms.
The former Victoria University of Manchester, now the University of Manchester, was founded in 1851 as Owens College. In 1880, the college joined the federal Victoria University, gaining an independent university charter in 1904 as the Victoria University of Manchester after the collapse of the federal university.
Sir Frederic Calland Williams,, known as F.C. Williams or Freddie Williams, was an English engineer, a pioneer in radar and computer technology.
The machine was not intended to be a practical computer, but was instead designed as a testbed for the Williams tube, the first truly random-access computer memory. Although considered "small and primitive" even by the standards of its own time, it was nonetheless the first working machine to contain all the elements essential to a modern electronic computer. Manchester Mark 1 . The Mark 1 in turn quickly became the prototype for the Ferranti Mark 1, the world's first commercially available general-purpose computer.As soon as the Baby had demonstrated the feasibility of its design, a project was initiated at the university to develop it into a more usable computer, the
A testbed is a platform for conducting rigorous, transparent, and replicable testing of scientific theories, computational tools, and new technologies.
The Williams tube, or the Williams–Kilburn tube after inventors Freddie Williams and Tom Kilburn, is an early form of computer memory. It was the first random-access digital storage device, and was used successfully in several early computers.
Random-access memory is a form of computer data storage that stores data and machine code currently being used. A random-access memory device allows data items to be read or written in almost the same amount of time irrespective of the physical location of data inside the memory. In contrast, with other direct-access data storage media such as hard disks, CD-RWs, DVD-RWs and the older magnetic tapes and drum memory, the time required to read and write data items varies significantly depending on their physical locations on the recording medium, due to mechanical limitations such as media rotation speeds and arm movement.
The Baby had a 32-bit word length and a memory of 32 words (1 kilobit). As it was designed to be the simplest possible stored-program computer, the only arithmetic operations implemented in hardware were subtraction and negation; other arithmetic operations were implemented in software. The first of three programs written for the machine calulated the highest proper divisor of 218 (262,144), an algorithm that would take a long time to execute—and so prove the computer's reliability—by testing every integer from 218 downwards, as division was implemented by repeated subtraction of the divisor. The program consisted of 17 instructions and ran for 52 minutes before reaching the correct answer of 131,072, after the Baby had performed 3.5 million operations (for an effective CPU speed of 1.1 kIPS).
The bit is a basic unit of information in information theory, computing, and digital communications. The name is a portmanteau of binary digit.
In computing, a word is the natural unit of data used by a particular processor design. A word is a fixed-sized piece of data handled as a unit by the instruction set or the hardware of the processor. The number of bits in a word is an important characteristic of any specific processor design or computer architecture.
In computing, memory refers to the computer hardware integrated circuits that store information for immediate use in a computer; it is synonymous with the term "primary storage". Computer memory operates at a high speed, for example random-access memory (RAM), as a distinction from storage that provides slow-to-access information but offers higher capacities. If needed, contents of the computer memory can be transferred to secondary storage; a very common way of doing this is through a memory management technique called "virtual memory". An archaic synonym for memory is store.
The first design for a program-controlled computer was Charles Babbage's Analytical Engine in the 1830s. A century later, in 1936, mathematician Alan Turing published his description of what became known as a Turing machine, a theoretical concept intended to explore the limits of mechanical computation. Turing was not imagining a physical machine, but a person he called a "computer", who acted according to the instructions provided by a tape on which symbols could be read and written sequentially as the tape moved under a tape head. Turing proved that if an algorithm can be written to solve a mathematical problem, then a Turing machine can execute that algorithm.
Charles Babbage was an English polymath. A mathematician, philosopher, inventor and mechanical engineer, Babbage originated the concept of a digital programmable computer.
The Analytical Engine was a proposed mechanical general-purpose computer designed by English mathematician and computer pioneer Charles Babbage. It was first described in 1837 as the successor to Babbage's difference engine, a design for a simpler mechanical computer.
Alan Mathison Turing was an English mathematician, computer scientist, logician, cryptanalyst, philosopher and theoretical biologist. Turing was highly influential in the development of theoretical computer science, providing a formalisation of the concepts of algorithm and computation with the Turing machine, which can be considered a model of a general-purpose computer. Turing is widely considered to be the father of theoretical computer science and artificial intelligence. Despite these accomplishments, he was never fully recognised in his home country during his lifetime, due to his homosexuality, which was then a crime in the UK.
Konrad Zuse's Z3 was the world's first working programmable, fully automatic computer, with binary digital arithmetic logic, but it lacked the conditional branching of a Turing machine. On 12 May 1941, it was successfully presented to an audience of scientists of the Deutsche Versuchsanstalt für Luftfahrt ("German Laboratory for Aviation") in Berlin.The Z3 stored its program on an external tape, but it was electromechanical rather than electronic. The Colossus of 1943 was the first electronic computing device, but it was not a general-purpose machine.
Konrad Zuse was a German civil engineer, inventor and computer pioneer. His greatest achievement was the world's first programmable computer; the functional program-controlled Turing-complete Z3 became operational in May 1941. Thanks to this machine and its predecessors, Zuse has often been regarded as the inventor of the modern computer.
The Z3 was a German electromechanical computer designed by Konrad Zuse. It was the world's first working programmable, fully automatic digital computer. The Z3 was built with 2,600 relays, implementing a 22-bit word length that operated at a clock frequency of about 4–5 Hz. Program code was stored on punched film. Initial values were entered manually.
Computer programming is the process of designing and building an executable computer program for accomplishing a specific computing task. Programming involves tasks such as: analysis, generating algorithms, profiling algorithms' accuracy and resource consumption, and the implementation of algorithms in a chosen programming language. The source code of a program is written in one or more languages. The purpose of programming is to find a sequence of instructions that will automate the performance of a task on a computer, often for solving a given problem. The process of programming thus often requires expertise in several different subjects, including knowledge of the application domain, specialized algorithms, and formal logic.
The ENIAC (1946) was the first machine that was both electronic and general purpose. It was Turing complete, with conditional branching, and programmable to solve a wide range of problems, but its program was held in the state of switches in patchcords, not in memory, and it could take several days to reprogram.Researchers such as Turing and Zuse investigated the idea of using the computer's memory to hold the program as well as the data it was working on, and it was mathematician John von Neumann who wrote a widely distributed paper describing that computer architecture, still used in almost all computers.
ENIAC was amongst the earliest electronic general-purpose computers made. It was Turing-complete, digital and able to solve "a large class of numerical problems" through reprogramming.
In computability theory, a system of data-manipulation rules is said to be Turing complete or computationally universal if it can be used to simulate any Turing machine. This means that this system is able to recognize or decide other data-manipulation rule sets. Turing completeness is used as a way to express the power of such data-manipulation rule set. The expression power of these grammars is captured in the Chomsky hierarchy. Virtually all programming languages today are Turing Complete. The concept is named after English mathematician and computer scientist Alan Turing.
John von Neumann was a Hungarian-American mathematician, physicist, computer scientist, and polymath. Von Neumann was generally regarded as the foremost mathematician of his time and said to be "the last representative of the great mathematicians"; a genius who was comfortable integrating both pure and applied sciences.
The construction of a von Neumann computer depended on the availability of a suitable memory device on which to store the program. During the Second World War researchers working on the problem of removing the clutter from radar signals had developed a form of delay line memory, the first practical application of which was the mercury delay line,developed by J. Presper Eckert. Radar transmitters send out regular brief pulses of radio energy, the reflections from which are displayed on a CRT screen. As operators are usually interested only in moving targets, it was desirable to filter out any distracting reflections from stationary objects. The filtering was achieved by comparing each received pulse with the previous pulse, and rejecting both if they were identical, leaving a signal containing only the images of any moving objects. To store each received pulse for later comparison it was passed through a transmission line, delaying it by exactly the time between transmitted pulses.
Turing joined the National Physical Laboratory (NPL) in October 1945,by which time scientists within the Ministry of Supply had concluded that Britain needed a National Mathematical Laboratory to co-ordinate machine-aided computation. A Mathematics Division was set up at the NPL, and on 19 February 1946 Alan Turing presented a paper outlining his design for an electronic stored-program computer to be known as the Automatic Computing Engine (ACE). This was one of several projects set up in the years following the Second World War with the aim of constructing a stored-program computer. At about the same time, EDVAC was under development at the University of Pennsylvania's Moore School of Electrical Engineering, and the University of Cambridge Mathematical Laboratory was working on EDSAC.
The NPL did not have the expertise to build a machine like ACE, so they contacted Tommy Flowers at the General Post Office's (GPO) Dollis Hill Research Laboratory. Flowers, the designer of Colossus, the world's first programmable electronic computer, was committed elsewhere and was unable to take part in the project, although his team did build some mercury delay lines for ACE.The Telecommunications Research Establishment (TRE) was also approached for assistance, as was Maurice Wilkes at the University of Cambridge Mathematical Laboratory.
The government department responsible for the NPL decided that, of all the work being carried out by the TRE on its behalf, ACE was to be given the top priority.NPL's decision led to a visit by the superintendent of the TRE's Physics Division on 22 November 1946, accompanied by Frederic C. Williams and A. M. Uttley, also from the TRE. Williams led a TRE development group working on CRT stores for radar applications, as an alternative to delay lines. Williams was not available to work on the ACE because he had already accepted a professorship at the University of Manchester, and most of his circuit technicians were in the process of being transferred to the Department of Atomic Energy. The TRE agreed to second a small number of technicians to work under Williams' direction at the university, and to support another small group working with Uttley at the TRE.
Although early computers such as EDSAC made successful use of mercury delay line memory,the technology had several drawbacks; it was heavy, it was expensive, and it did not allow data to be accessed randomly. In addition, because data was stored as a sequence of acoustic waves propagated through a mercury column, the device's temperature had to be very carefully controlled, as the velocity of sound through a medium varies with its temperature. Williams had seen an experiment at Bell Labs demonstrating the effectiveness of cathode ray tubes (CRT) as an alternative to the delay line for removing ground echoes from radar signals. While working at the TRE, shortly before he joined the University of Manchester in December 1946, he and Tom Kilburn had developed a form of electronic memory known as the Williams tube or Williams–Kilburn tube, based on a standard CRT, the first random-access digital storage device. The Baby was designed to show that the system was a practical storage device, by testing that data held within it could be read and written at the speed necessary for use in a computer.
For use in a binary digital computer, the tube had to be capable of storing either one of two states at each of its memory locations, corresponding to the binary digits (bits) 0 and 1. It exploited the positive or negative electric charge generated by displaying either a dash or a dot at any position on the CRT screen, a phenomenon known as secondary emission. A dash generated a positive charge, and a dot a negative charge, either of which could be picked up by a detector plate in front of the screen; a negative charge represented 0, and a positive charge 1. The charge dissipated in about 0.2 seconds, but it could be automatically refreshed from the data picked up by the detector.
The Williams tube used in Baby was based on the CV1131, a commercially available 12-inch (300 mm) diameter CRT, but a smaller 6-inch (150 mm) tube, the CV1097, was used in the Mark I.
After developing the Colossus computer for code breaking at Bletchley Park during World War II, Max Newman was committed to the development of a computer incorporating both Alan Turing's mathematical concepts and the stored-program concept that had been described by John von Neumann. In 1945, he was appointed to the Fielden Chair of Pure Mathematics at Manchester University; he took his Colossus-project colleagues Jack Good and David Rees to Manchester with him, and there they recruited F. C. Williams to be the "circuit man" for a new computer project for which he had secured funding from the Royal Society.
"Having secured the support of the university, obtained funding from the Royal Society, and assembled a first-rate team of mathematicians and engineers, Newman now had all elements of his computer-building plan in place. Adopting the approach he had used so effectively at Bletchley Park, Newman set his people loose on the detailed work while he concentrated on orchestrating the endeavor."
Following his appointment to the Chair of Electrical Engineering at Manchester University, Williams recruited his TRE colleague Tom Kilburn on secondment. By the autumn of 1947 the pair had increased the storage capacity of the Williams tube from one bit to 2,048, arranged in a 64 by 32-bit array,and demonstrated that it was able to store those bits for four hours. Engineer Geoff Tootill joined the team on loan from TRE in September 1947, and remained on secondment until April 1949.
"Now let's be clear before we go any further that neither Tom Kilburn nor I knew the first thing about computers when we arrived at Manchester University ... Newman explained the whole business of how a computer works to us."
Kilburn had a hard time recalling the influences on his machine design:
"[I]n that period, somehow or other I knew what a digital computer was . . . Where I got this knowledge from I’ve no idea."
Jack Copeland explains that Kilburn's first (pre-Baby) accumulator-free (decentralized, in Jack Good's nomenclature) design was based on inputs from Turing, but that he later switched to an accumulator-based (centralized) machine of the sort advocated by von Neumann, as written up and taught to him by Jack Good and Max Newman.
The Baby's 7-op instruction set was approximately a subset of the 12-op instruction set proposed in 1947 by Jack Good, in the first known document to use the term "Baby" for this machine.Good did not include a "halt" instruction, and his proposed conditional jump instruction was more complicated than what the Baby implemented.
Although Newman played no engineering role in the development of the Baby, or any of the subsequent Manchester computers, he was generally supportive and enthusiastic about the project, and arranged for the acquisition of war-surplus supplies for its construction, including GPO metal racksand "…the material of two complete Colossi" from Bletchley.
By June 1948 the Baby had been built and was working. 17 feet (5.2 m) in length, 7 feet 4 inches (2.24 m) tall, and weighed almost 1 long ton (1.0 t). The machine contained 550 valves (vacuum tubes)—300 diodes and 250 pentodes—and had a power consumption of 3500 watts. The arithmetic unit was built using EF50 pentode valves, which had been widely used during wartime. The Baby used one Williams tube to provide 32 by 32-bit words of random-access memory (RAM), a second to hold a 32-bit accumulator in which the intermediate results of a calculation could be stored temporarily, and a third to hold the current program instruction along with its address in memory. A fourth CRT, without the storage electronics of the other three, was used as the output device, able to display the bit pattern of any selected storage tube.It was
Each 32-bit word of RAM could contain either a program instruction or data. In a program instruction, bits 0–12 represented the memory address of the operand to be used, and bits 13–15 specified the operation to be executed, such as storing a number in memory; the remaining 16 bits were unused. The Baby's 0-operand instruction set|single operand architecture meant that the second operand of any operation was implicit: the accumulator or the program counter (instruction address); program instructions specified only the address of the data in memory.
A word in the computer's memory could be read, written, or refreshed, in 360 microseconds. An instruction took four times as long to execute as accessing a word from memory, giving an instruction execution rate of about 700 per second. The main store was refreshed continuously, a process that took 20 milliseconds to complete, as each of the Baby's 32 words had to be read and then refreshed in sequence.
The Baby represented negative numbers using two's complement, − 1 (decimal: −2,147,483,648 to +2,147,483,647).as most computers still do. In that representation, the value of the most significant bit denotes the sign of a number; positive numbers have a zero in that position and negative numbers a one. Thus, the range of numbers that could be held in each 32-bit word was −231 to +231
The Baby's instruction format had a three-bit operation code field, which allowed a maximum of eight (23) different instructions. In contrast to the modern convention, the machine's storage was described with the least significant digits to the left; thus a one was represented in three bits as "100", rather than the more conventional "001".
|Binary code||Original notation||Modern mnemonic||Operation|
|000||S, Cl||JMP S||Jump to the instruction at the address obtained from the specified memory address S (absolute unconditional jump)|
|100||Add S, Cl||JRP S||Jump to the instruction at the program counter plus (+) the relative value obtained from the specified memory address S (relative unconditional jump)|
|010||-S, C||LDN S||Take the number from the specified memory address S, negate it, and load it into the accumulator|
|110||c, S||STO S||Store the number in the accumulator to the specified memory address S|
|SUB S||SUB S||Subtract the number at the specified memory address S from the value in accumulator, and store the result in the accumulator|
|011||Test||CMP||Skip next instruction if the accumulator contains a negative value|
The awkward negative operations were a consequence of the Baby's lack of hardware to perform any arithmetic operations except subtraction and negation. It was considered unnecessary to build an adder before testing could begin as addition can easily be implemented by subtraction,i.e. x+y can be computed as −(−x−y). Therefore, adding two numbers together, X and Y, required four instructions:
LDN X // load negative X into the accumulator SUB Y // subtract Y from the value in the accumulator STO S // store the result at S LDN S // load negative value at S into the accumulator
Programs were entered in binary form by stepping through each word of memory in turn, and using a set of 32 buttons and switches known as the input device to set the value of each bit of each word to either 0 or 1. The Baby had no paper-tape reader or punch.
Three programs were written for the computer. The first, consisting of 17 instructions, was written by Kilburn, and so far as can be ascertained first ran on 21 June 1948. It was designed to find the highest proper factor of 218 (262,144) by trying every integer from 218 − 1 downwards. The divisions were implemented by repeated subtractions of the divisor. The Baby took 3.5 million operations and 52 minutes to produce the answer (131,072). The program used eight words of working storage in addition to its 17 words of instructions, giving a program size of 25 words.
Geoff Tootill wrote an amended version of the program the following month, and in mid-July Alan Turing — who had been appointed as a reader in the mathematics department at Manchester University in September 1948 — submitted the third program, to carry out long division. Turing had by then been appointed to the nominal post of Deputy Director of the Computing Machine Laboratory at the university, although the laboratory did not become a physical reality until 1951.
Williams and Kilburn reported on the Baby in a letter to the Journal Nature , published in September 1948. Manchester Mark 1 , work on which began in August 1948. The first version was operational by April 1949, and it in turn led directly to the development of the Ferranti Mark 1, the world's first commercially available general-purpose computer.The machine's successful demonstration quickly led to the construction of a more practical computer, the
In 1998, a working replica of the Baby, now on display at the Museum of Science and Industry in Manchester, was built to celebrate the 50th anniversary of the running of its first program. Demonstrations of the machine in operation are held regularly at the museum.In 2008, an original panoramic photograph of the entire machine was discovered at the University of Manchester. The photograph, taken on 15 December 1948 by a research student, Alec Robinson, had been reproduced in The Illustrated London News in June 1949.
The Electronic delay storage automatic calculator (EDSAC) was an early British computer. Inspired by John von Neumann's seminal First Draft of a Report on the EDVAC, the machine was constructed by Maurice Wilkes and his team at the University of Cambridge Mathematical Laboratory in England. EDSAC was the second electronic digital stored-program computer to go into regular service.
The history of computing hardware covers the developments from early simple devices to aid calculation to modern day computers. Before the 20th century, most calculations were done by humans. Early mechanical tools to help humans with digital calculations, like the abacus, were called "calculating machines", called by proprietary names, or referred to as calculators. The machine operator was called the computer.
The IAS machine was the first electronic computer to be built at the Institute for Advanced Study (IAS) in Princeton, New Jersey. It is sometimes called the von Neumann machine, since the paper describing its design was edited by John von Neumann, a mathematics professor at both Princeton University and IAS. The computer was built from late 1945 until 1951 under his direction. The general organization is called Von Neumann architecture, even though it was both conceived and implemented by others. The computer is in the collection of the Smithsonian National Museum of American History but is not currently on display.
The von Neumann architecture—also known as the von Neumann model or Princeton architecture—is a computer architecture based on a 1945 description by the mathematician and physicist John von Neumann and others in the First Draft of a Report on the EDVAC. That document describes a design architecture for an electronic digital computer with these components:
The School of Computer Science at the University of Manchester is the longest established school of Computer Science in the United Kingdom and one of the largest. It is located in the Kilburn building on the Oxford Road and currently has over 800 students taking a wide range of undergraduate and postgraduate courses and 60 full-time academic staff.
The Ferranti Mark 1, also known as the Manchester Electronic Computer in its sales literature, and thus sometimes called the Manchester Ferranti, was the world's first commercially available general-purpose electronic computer. It was "the tidied up and commercialised version of the Manchester computer". The first machine was delivered to the Victoria University of Manchester in February 1951 ahead of the UNIVAC I, which was supplied to the United States Census Bureau on 31 March 1951, although not delivered until late December the following year.
Tom Kilburn was an English mathematician and computer scientist. Over the course of a productive 30-year career, he was involved in the development of five computers of great historical significance. With Freddie Williams he worked on the Williams–Kilburn tube and the world's first electronic stored-program computer, the Manchester Baby, while working at the University of Manchester. His work propelled Manchester and Britain into the forefront of the emerging field of computer science.
The Automatic Computing Engine (ACE) was a British early electronic stored-program computer designed by Alan Turing.
The Metrovick 950 was a transistorized computer, built from 1956 onwards by British company Metropolitan-Vickers, to the extent of six or seven machines, which were "used commercially within the company" or "mainly for internal use". The 950 appears to have been Metrovick's first and last commercial computer offering.
Mary Lee Woods was an English mathematician and computer programmer who worked in a team that developed programs in the School of Computer Science, University of Manchester Mark 1, Ferranti Mark 1 and Mark 1 Star computers. She met and married Conway Berners-Lee while working at Ferranti. Sir Tim Berners-Lee is one of their children.
Geoff C. Tootill was an electronic engineer and computer scientist who worked in the Electrical Engineering Department at the University of Manchester with Freddie Williams and Tom Kilburn developing the Manchester Baby, "the world's first wholly electronic stored-program computer".
The Atlas Computer was one of the world's first supercomputers, in use from 1962 until 1971. It was considered to be the most powerful computer in the world at that time. It is notable for being the first machine with virtual memory using paging techniques; this approach quickly spread, and is now ubiquitous.
The Manchester computers were an innovative series of stored-program electronic computers developed during the 30-year period between 1947 and 1977 by a small team at the University of Manchester, under the leadership of Tom Kilburn. They included the world's first stored-program computer, the world's first transistorised computer, and what was the world's fastest computer at the time of its inauguration in 1962.
The Manchester Mark 1 was one of the earliest stored-program computers, developed at the Victoria University of Manchester from the Manchester Baby. It was also called the Manchester Automatic Digital Machine, or MADM. Work began in August 1948, and the first version was operational by April 1949; a program written to search for Mersenne primes ran error-free for nine hours on the night of 16/17 June 1949.
The Computing Machine Laboratory at the University of Manchester in the north of England was established by Max Newman shortly after the end of World War II, around 1946.
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