This article is about the early British computer. The term "Manchester Mark I" can also refer to the Avro Manchester heavy bomber in RAF service during the early stages of World War II. The Avro 679 Manchester was a British twin-engined Heavy bomber developed during the Second World War by the Avro aircraft company in the

Manchester Mark 1 was one of the world's first stored program computers.

The Manchester Mark I was one of the earliest electronic computers, built at the University of Manchester in England, in 1949. A computer is a Machine that manipulates data according to a list of instructions. The University of Manchester is a " red brick " civic University located in Manchester, England. England is a Country which is part of the United Kingdom. Its inhabitants account for more than 83% of the total UK population whilst its mainland Year 1949 ( MCMXLIX) was a Common year starting on Saturday (link will display the full calendar of the Gregorian calendar. It was also called Manchester Automatic Digital Machine, or MADM. It was developed from the Small-Scale Experimental Machine (SSEM) or "Baby". The Manchester Small-Scale Experimental Machine (SSEM, nicknamed Baby, was the world's first stored-program Computer. It is especially historically significant due to its pioneering inclusion of a kind of index register in its architecture, as well as being the platform on which Autocode was developed, one of the first "high-level" computer languages. An index register in a computer's CPU is a Processor register used for modifying Operand addresses during the run of a program typically for doing vector/ Autocode is the name of a family of High-level programming languages devised in the 50's and 60's for a series of Digital computers at the Universities of Manchester

Development of the Mark I started after the SSEM demonstrated the utility of the stored-program approach, which dramatically improved a machine's flexibility. This approach was being looked at by other researchers, notably Alan Turing's efforts on the Pilot ACE, Cambridge University's EDSAC, and EDVAC in the US. Alan Mathison Turing, OBE, FRS (ˈt(jʊ(ərɪŋ (23 June 1912 &ndash 7 June 1954 was an English Mathematician The Pilot ACE was one of the first Computers built in the United Kingdom, at the National Physical Laboratory (NPL in the early 1950s The University of Cambridge (often Cambridge University) located in Cambridge, England, is the second-oldest university in the Electronic Delay Storage Automatic Calculator ( EDSAC) was an early British Computer. EDVAC ( E lectronic D iscrete V ariable A utomatic C omputer) was one of the earliest electronic Computers The SSEM differed primarily in the choice of memory system, using the much faster Williams tubes instead of mercury delay lines. The Williams tube or the Williams-Kilburn tube (after inventors Freddie Williams and Tom Kilburn) developed about 1946 or 1947 Genesis in radar The basic concept of the delay line originated with World War II Radar research as a system to reduce clutter from reflections from the ground

With the successful demonstration of the SSEM, the British government contracted Ferranti in October 1948 to deliver a full-scale machine based on its basic concepts. Ferranti or Ferranti International plc was a major UK Electrical engineering and equipment firm known primarily for defence Electronics and Key improvements in the design were going to include a magnetic drum for loading programs into the machine's Williams tube memory, replacing the SSEM's paper tape, the addition of index registers and a hardware multiplier. Drum memory is a magnetic Data storage device and was an early form of Computer memory widely used in the 1950s and into the 1960s invented by Gustav Tauschek Punched tape or paper tape is a largely obsolete form of Data storage, consisting of a long strip of paper in which holes are punched to store data The word size was increased slightly from 32-bits to 40, read and written as four 10-bit "short words". Instructions used a single short word, addresses two, and numeric data four. Although the 10-bit instructions could hold up to 1,024 different codes, the machine only had 30 in its final version. Standard instruction time was 1,800 microseconds, but multiplication was much slower. To help compare Orders of magnitude of different Times this page lists times between 10&minus6 seconds and 10&minus5 seconds (1 micro The Ferranti Mark 1 (based on the Manchester Mark 1) had an addition time of 1,200 microseconds and a multiplication time of 2,160 microseconds. Ferranti or Ferranti International plc was a major UK Electrical engineering and equipment firm known primarily for defence Electronics and

The SSEM included two registers on its Williams tube, the accumulator A and program counter C. In a Computer 's central processing unit ( CPU) an accumulator is a register in which intermediate arithmetic and logic results are stored The program counter, or shorter PC (also called the instruction pointer, part of the instruction sequencer in some Computers is a register in Mark I added another, D, for holding one side of a multiplication, leaving B the natural place to hold the index register. An index register in a computer's CPU is a Processor register used for modifying Operand addresses during the run of a program typically for doing vector/ Since the system used a 20-bit address, the B-line on the tube held two address offsets. This is the earliest known implementation of such index/base registers – an important innovation in computer architecture, unknown in other machines until the emergence of second-generation computers (approximately 1955–1964). The history of computer hardware encompasses the hardware, its architecture, and its impact on software. The Mark I included two tubes, each storing 64 rows ("double density") of 40 points, for a total of 128 words. 64 words was considered to be a single "page", so the system stored 4 pages. Freddie Williams deliberately sized the drum to store two "pages" of Williams tube data – that is, 2x32x40 = 2,560 bits – per track, and 32 tracks in total. Sir Frederic Calland Williams ( June 26, 1911. Stockport &ndash August 11 1977. The drum was timed to spin at the refresh rate of the Willams tubes, allowing pages to be read and written between refreshes, a task that took about 30 cycles.

The first version of the machine was running in April 1949, known as the Intermediary Version. This version was largely feature complete, but lacked input/output instructions to move data from the drum to the tubes or paper tape to the drum. In Computing, input/output, or I/O, refers to the communication between an Information processing system (such as a Computer) and the outside

The first realistic program to be run on the Mark I was a test of Mersenne primes, run in early April 1949. In Mathematics, a Mersenne number is a positive integer that is one less than a Power of two: M_n=2^n-1 The computer ran error-free for 9 hours on the night of June 16-17, 1949. The Final Specification version was completed in October 1949, adding a second drum and various instructions to read one line of data to and from the drum to tubes and drum to paper tape. Over time the existing drums were used to store more data, typically 47 tracks.

The machine used 4,200 vacuum tubes for logic, which proved to be a terrible reliability problem. This article is about the electronic device not an evacuated pipe used for experiments in Free-fall. In one calculation the machine spent almost 25% of its time "down", due both to the tubes and the drums. Downtime or outage refers to a period of time or a percentage of a timespan that a System is unavailable or Offline. Nevertheless the University was successful in attracting commercial users to rent time on the machine for £50 an hour.

After the Mark I was running, development continued in several directions. Dick Grimsdale and Doug Webb attempted to improve the reliability of the Mark I by building the machine out of transistors, perhaps being the first transistorized computer when their prototype ran in November 1953. Richard Lawrence Grimsdale, ( September 18, 1929 – December 6, 2005) was a British electrical engineer and computer pioneer who In Electronics, a transistor is a Semiconductor device commonly used to amplify or switch electronic signals Their work was later picked up by Metropolitan-Vickers to create the Metrovick 950, of which seven were sold. Metropolitan-Vickers, Metrovick, or Metrovicks, was a British heavy electrical engineering company of the early-to-mid 20th century formerly known as The Metrovick 950 was the first commercial Transistor computer, built from 1959 onwards by British company Metropolitan-Vickers to the extent

The main Mark I team, Tom Kilburn and Freddie Williams, concluded that computers would be used more in scientific roles than pure math, and decided to start development of a new model including a floating point unit. Tom Kilburn ( August 11, 1921 - January 17, 2001) was an English Engineer. Freddie Williams could refer to any of these people Frederic Calland Williams (1911-1977 English engineer Freddie Williams (speedway rider A floating point unit (FPU is a part of a Computer system specially designed to carry out operations on Floating point numbers The resulting machine, Meg, was both simpler than the Mark I as well as much faster for math problems. Ferranti, who had built the Mark I, rebuilt Meg with core memory and sold the resulting design as the Ferranti Mercury. Ferranti or Ferranti International plc was a major UK Electrical engineering and equipment firm known primarily for defence Electronics and Magnetic core memory, or ferrite-core memory, is an early form of Random access Computer memory. The Mercury was an early 1950s commercial Computer built by Ferranti.

Among the Mark I team were mathematicians Conway Berners-Lee and Mary Lee Woods, who would later marry; their son, Tim Berners-Lee, is acknowledged as the inventor of the World Wide Web. Conway Berners-Lee (born 1921 is an English mathematician who worked in the team that developed the Manchester Mark I computer at the University of Mary Lee Woods is a British mathematician who worked in the team that developed the Manchester Mark I computer at the University of Manchester Sir Timothy John Berners-Lee OM KBE FRS FREng FRSA (born 8 June 1955 is an English computer scientist who is credited The World Wide Web (commonly shortened to the Web) is a system of interlinked Hypertext documents accessed via the Internet.

The Met. Office used the Mark I to develop its first prototype computer programs for weather forecasting; they used difference equations to calculate atmospheric pressure.

References

• Lavington, Simon H. The history of computer hardware encompasses the hardware, its architecture, and its impact on software. Computer programs (also software programs, or just programs) are instructions for a Computer. In computability theory, several closely-related terms are used to describe the "computational power" of a computational system (such as an Abstract machine or Konrad Zuse (ˈkɔnʁat ˈtsuːzə June 22, 1910 Berlin - December 18, 1995 Hünfeld) was a German Konrad Zuse 's Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. In Engineering, electromechanics combines the Sciences of Electromagnetism of Electrical engineering and mechanics. This focuses on Motion picture film For Still photography film see Photographic film. Konrad Zuse 's The Atanasoff–Berry Computer ( ABC) was the first electronic Digital Computing device The United States of America —commonly referred to as the The Colossus machines were electronic Computing devices used by British codebreakers to read Encrypted German messages during The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located The IBM Automatic Sequence Controlled Calculator ( ASCC) called the Mark I by Harvard University, was the first large-scale automatic digital The United States of America —commonly referred to as the The decimal ( base ten or occasionally denary) Numeral system has ten as its base. In Engineering, electromechanics combines the Sciences of Electromagnetism of Electrical engineering and mechanics. Punched tape or paper tape is a largely obsolete form of Data storage, consisting of a long strip of paper in which holes are punched to store data Konrad Zuse 's ENIAC, short for Electronic Numerical Integrator And Computer, was the first general-purpose electronic Computer. The United States of America —commonly referred to as the The decimal ( base ten or occasionally denary) Numeral system has ten as its base. The Manchester Small-Scale Experimental Machine (SSEM, nicknamed Baby, was the world's first stored-program Computer. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located The von Neumann architecture is a design model for a stored-program Digital computer that uses a processing unit and a single separate storage structure The Williams tube or the Williams-Kilburn tube (after inventors Freddie Williams and Tom Kilburn) developed about 1946 or 1947 ENIAC, short for Electronic Numerical Integrator And Computer, was the first general-purpose electronic Computer. The United States of America —commonly referred to as the The decimal ( base ten or occasionally denary) Numeral system has ten as its base. Electronic Delay Storage Automatic Calculator ( EDSAC) was an early British Computer. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located The von Neumann architecture is a design model for a stored-program Digital computer that uses a processing unit and a single separate storage structure Genesis in radar The basic concept of the delay line originated with World War II Radar research as a system to reduce clutter from reflections from the ground The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located The Williams tube or the Williams-Kilburn tube (after inventors Freddie Williams and Tom Kilburn) developed about 1946 or 1947 Drum memory is a magnetic Data storage device and was an early form of Computer memory widely used in the 1950s and into the 1960s invented by Gustav Tauschek CSIRAC ( C ouncil for S cientific and I ndustrial R esearch A utomatic C omputer, pronounced /'sаɪræk/ For a topic outline on this subject see List of basic Australia topics. The von Neumann architecture is a design model for a stored-program Digital computer that uses a processing unit and a single separate storage structure Genesis in radar The basic concept of the delay line originated with World War II Radar research as a system to reduce clutter from reflections from the ground (1980). Early British Computers. Manchester University Press. ISBN 0-932376-08-8.  

External links

• The Manchester Mark I
• Early computers at Manchester University
• A simulator of the Manchester Mark I, executing Christopher Strachey's Love letter algorithm from 1952
• Lavington, Simon H. (Jul-Sept 1993). "Manchester Computer Architectures, 1948-1975". IEEE Annals of the History of Computing 15 (3): 44-54. IEEE. doi:http://doi.ieeecomputersociety.org/10.1109/85.222841. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.