Percy Edwin Ludgate (2 August 1883 – 16 October 1922) was an
Irish
Irish may refer to:
Common meanings
* Someone or something of, from, or related to:
** Ireland, an island situated off the north-western coast of continental Europe
***Éire, Irish language name for the isle
** Northern Ireland, a constituent unit ...
amateur scientist who designed the second
analytical engine
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, which was a design ...
(general-purpose
Turing-complete
In computability theory, a system of data-manipulation rules (such as a computer's instruction set, a programming language, or a cellular automaton) is said to be Turing-complete or computationally universal if it can be used to simulate any Tur ...
computer) in history.
Life
Ludgate was born on 2 August 1883 in
Skibbereen
Skibbereen (; ) is a town in County Cork, Ireland. It is located in West Cork on the N71 national secondary road. The name "Skibbereen" (sometimes shortened to "Skibb") means "little boat harbour". The River Ilen runs through the town; it reac ...
,
County Cork
County Cork ( ga, Contae Chorcaí) is the largest and the southernmost county of Ireland, named after the city of Cork, the state's second-largest city. It is in the province of Munster and the Southern Region. Its largest market towns are ...
, to Michael Ludgate and Mary McMahon.
In the 1901 census, he is listed as
Civil Servant
The civil service is a collective term for a sector of government composed mainly of career civil servants hired on professional merit rather than appointed or elected, whose institutional tenure typically survives transitions of political leader ...
National Education (Boy Copyist) in
Dublin. In the 1911 census, he is also in Dublin, as a Commercial Clerk (Corn Merchant). He studied accountancy at
Rathmines College of Commerce, earning a gold medal based on the results his final examinations in 1917.
At some date before or after then, he joined Kevans & Son, accountants.
Work on analytical engine
It seems that Ludgate worked as a clerk for an unknown corn merchants, in Dublin, and pursued his interest in calculating machines at night.
[ ]Charles Babbage
Charles Babbage (; 26 December 1791 – 18 October 1871) was an English polymath. A mathematician, philosopher, inventor and mechanical engineer, Babbage originated the concept of a digital programmable computer.
Babbage is considered ...
in 1843 and Ludgate in 1909 designed the only two mechanical analytical engines before the electromechanical analytical engine of Leonardo Torres y Quevedo of 1920 and its few successors, and the six first-generation electronic
Electronic may refer to:
*Electronics, the science of how to control electric energy in semiconductor
* ''Electronics'' (magazine), a defunct American trade journal
*Electronic storage, the storage of data using an electronic device
*Electronic co ...
analytical engines of 1949.
Working alone, Ludgate designed an analytical engine while unaware of Babbage's designs, although he later went on to write about Babbage's machine. Ludgate's engine used multiplication as its base mechanism (unlike Babbage's which used addition). It incorporated the first multiplier-accumulator, and was the first to exploit a multiplier-accumulator to perform division, using multiplication seeded by reciprocal, via the convergent series .
Ludgate's engine also used a mechanism similar to slide rules, but employing his unique discrete Logarithmic Indexes (now known as Irish logarithms), and provided a very novel memory using concentric cylinders, storing numbers as displacements of rods in shuttles. His design featured several other novel features, including for program control (e.g., preemption and subroutines – or microcode
In processor design, microcode (μcode) is a technique that interposes a layer of computer organization between the central processing unit (CPU) hardware and the programmer-visible instruction set architecture of a computer. Microcode is a lay ...
, depending on viewpoint). The design is so different from Babbage's as to be a second type of analytical engine
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, which was a design ...
, preceding the third ( electromechanical) and fourth (electronic
Electronic may refer to:
*Electronics, the science of how to control electric energy in semiconductor
* ''Electronics'' (magazine), a defunct American trade journal
*Electronic storage, the storage of data using an electronic device
*Electronic co ...
) types. The engine's precise mechanism is unknown as the only written accounts which survive do not detail its workings, although he stated in 1914 that " mplete descriptive drawings of the machine exist, as well as a description in manuscript" – these have never been found.
Ludgate was one of a few independent workers in the field of science and mathematics. His inventions were worked on outside a lab. He worked on them only part-time, often until the early hours of the morning. Many publications refer to him as an accountant, but that came eight years after his 1909 analytical engine paper. Little is known about his personal life, as his only records are his scientific writings. Until 2016 the best source of information about Ludgate and his significance lie in the work of Professor Brian Randell
Brian Randell (born 1936) is a British computer scientist, and Emeritus Professor at the School of Computing, Newcastle University, United Kingdom. He specialises in research into software fault tolerance and dependability, and is a noted auth ...
. As from then, a further investigation is underway at Trinity College, Dublin under the auspices of the John Gabriel Byrne Computer Science Collection.
Ludgate died of pneumonia in 19 October 1922, and is buried in Mount Jerome Cemetery in Dublin.[
]
Legacy
In 1991, a prize for the best final-year project in the Moderatorship in computer science course at Trinity College, Dublin – the Ludgate Prize – was instituted in his honour, and in 2016 the Ludgate Hub e-business incubation centre was opened in Skibbereen
Skibbereen (; ) is a town in County Cork, Ireland. It is located in West Cork on the N71 national secondary road. The name "Skibbereen" (sometimes shortened to "Skibb") means "little boat harbour". The River Ilen runs through the town; it reac ...
, where he was born.[
In October 2022, a plaque from the was unveiled at Ludgate's home in Drumcondra by the Provost of Trinity College, ]Linda Doyle
Linda E. Doyle is an Irish academic and educator who is the 45th provost and president of Trinity College Dublin (TCD), the university's chief officer. An electrical engineer, she has had a long academic career at Trinity, from the 1990s, most ...
.
References
Bibliography
* Available on-line at:
Fano.co.UK
*
* (A subscription to the journal or payment on a per-article basis is required to view this article) �
full version
*
*
* (extensive background and research document), and . In: online catalog of The John Gabriel Byrne Computer Science Collection
* Brian Coghlan (2019) "An exploration of the life of Percy Ludgate": and , presented at the West Cork History Festival 2019, Skibbereen, Ireland
* (see als
* (see als
* online catalog
* Mobile-friendly Ludgate folder of the above catalog
* (see Book Depositor
also see BookFinde
{{DEFAULTSORT:Ludgate, Percy
1883 births
1922 deaths
People from Skibbereen
20th-century Irish businesspeople
20th-century Irish scientists
Irish inventors
Businesspeople from Dublin (city)
Scientists from Dublin (city)
Computer designers
Deaths from pneumonia in the Republic of Ireland
Burials at Mount Jerome Cemetery and Crematorium