László "Les" Bélády (born April 29, 1928, in

Budapest Budapest (, ; ) is the capital and most populous city of Hungary. It is the ninth-largest city in the European Union by population within city limits and the second-largest city on the Danube river; the city has an estimated population ...

; died November 6, 2021) was a Hungarian

computer scientist A computer scientist is a person who is trained in the academic study of computer science. Computer scientists typically work on the theoretical side of computation, as opposed to the hardware side on which computer engineers mainly focus (al ...

notable for devising the Bélády's Min theoretical memory caching

algorithm In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algorithms are used as specificat ...

in 1966 while working at

IBM Research IBM Research is the research and development division for IBM, an American multinational information technology company headquartered in Armonk, New York, with operations in over 170 countries. IBM Research is the largest industrial research org ...

. He also demonstrated the existence of a Bélády's anomaly. During the 1980s, he was the

editor-in-chief An editor-in-chief (EIC), also known as lead editor or chief editor, is a publication's editorial leader who has final responsibility for its operations and policies. The highest-ranking editor of a publication may also be titled editor, managing ...

of the

IEEE Transactions on Software Engineering The ''IEEE Transactions on Software Engineering'' is a monthly peer-reviewed scientific journal published by the IEEE Computer Society. It was established in 1975 and covers the area of software engineering. It is considered the leading journal i ...

Education

Bélády earned

B.S. A Bachelor of Science (BS, BSc, SB, or ScB; from the Latin ') is a bachelor's degree awarded for programs that generally last three to five years. The first university to admit a student to the degree of Bachelor of Science was the University ...

Mechanical Engineering Mechanical engineering is the study of physical machines that may involve force and movement. It is an engineering branch that combines engineering physics and mathematics principles with materials science, to design, analyze, manufacture, and ...

, then an

M.S. A Master of Science ( la, Magisterii Scientiae; abbreviated MS, M.S., MSc, M.Sc., SM, S.M., ScM or Sc.M.) is a master's degree in the field of science awarded by universities in many countries or a person holding such a degree. In contrast to ...

Aeronautical Engineering Aerospace engineering is the primary field of engineering concerned with the development of aircraft and spacecraft. It has two major and overlapping branches: Aeronautics, aeronautical engineering and Astronautics, astronautical engineering. A ...

at the

Technical University of Budapest Technical may refer to: * Technical (vehicle), an improvised fighting vehicle * Technical analysis, a discipline for forecasting the future direction of prices through the study of past market data * Technical drawing, showing how something is co ...

in 1950.

Life and career

He left Hungary after the

Hungarian Revolution of 1956 The Hungarian Revolution of 1956 (23 October – 10 November 1956; hu, 1956-os forradalom), also known as the Hungarian Uprising, was a countrywide revolution against the government of the Hungarian People's Republic (1949–1989) and the Hunga ...

. Then he worked as a draftsman at

Ford Motor Company Ford Motor Company (commonly known as Ford) is an American multinational automobile manufacturer headquartered in Dearborn, Michigan, United States. It was founded by Henry Ford and incorporated on June 16, 1903. The company sells automobi ...

in Cologne and as an aerodynamics engineer at

Dassault Dassault Group (; also GIM Dassault or Groupe Industriel Marcel Dassault SAS) is a French group of companies established in 1929 with the creation of Société des Avions Marcel Bloch (now Dassault Aviation) by Marcel Dassault, and led by son Ser ...

in Paris. In 1961, he immigrated to the United States. In the 1960s and 1970s, he primarily lived in

New York City New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the L ...

with stints in

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

and

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

, where he joined International Business Machines and did early work in operating systems, virtual machine architectures, program behavior modeling, memory management, computer graphics, Asian character sets, and data security.Oral history interview with László A. Bélády

Charles Babbage Institute The IT History Society (ITHS) is an organization that supports the history and scholarship of information technology by encouraging, fostering, and facilitating archival and historical research. Formerly known as the Charles Babbage Foundation, ...

, University of Minnesota. From 1961 – 1981, he worked at IBM Corp. at the

Thomas J. Watson Research Center The Thomas J. Watson Research Center is the headquarters for IBM Research. The center comprises three sites, with its main laboratory in Yorktown Heights, New York, U.S., 38 miles (61 km) north of New York City, Albany, New York and with ...

, where he worked as

program manager Program Manager is the shell of Windows 3.x and Windows NT 3.x operating systems. This shell exposed a task-oriented graphical user interface (GUI), consisting of ''icons'' (shortcuts for programs) arranged into ''program groups''. It replaced ' ...

for

software Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work. At the lowest programming level, executable code consists ...

technology. In his later years at IBM, he was responsible for

software engineering Software engineering is a systematic engineering approach to software development. A software engineer is a person who applies the principles of software engineering to design, develop, maintain, test, and evaluate computer software. The term '' ...

worldwide until leaving for

Tokyo Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, with an estimated 37.468 ...

to create its software research lab. In 1981, he worked as manager of

Japan Science Institute IBM Research is the research and development division for IBM, an American multinational information technology company headquartered in Armonk, New York, with operations in over 170 countries. IBM Research is the largest industrial research org ...

for two years. In 1984, he joined the

Microelectronics and Computer Technology Corporation Microelectronics and Computer Technology Corporation, originally the Microelectronics and Computer Consortium and widely seen as the acronym MCC, was the first, and at one time one of the largest, computer industry research and development con ...

in Austin and founded its Software Technology Program. He focused the program on creating advanced technology for aiding the distributed design of large complex software systems. From 1991 to 1998, he served as president and CEO of

Mitsubishi Electric Research Laboratories Mitsubishi Electric Research Laboratories (MERL) is a subsidiary of Mitsubishi Electric US Holdings, Inc., which, in its turn, is the principal subsidiary of Mitsubishi Electric in the United States. MERL is the North American arm of the Corpora ...

, Inc. (MERL). He has been in various University advisory roles including a member of the computer science advisory board at the

University of Colorado at Boulder The University of Colorado Boulder (CU Boulder, CU, or Colorado) is a public research university in Boulder, Colorado. Founded in 1876, five months before Colorado became a state, it is the flagship university of the University of Colorado sys ...

and foreign member of the

Hungarian Academy of Sciences The Hungarian Academy of Sciences ( hu, Magyar Tudományos Akadémia, MTA) is the most important and prestigious learned society of Hungary. Its seat is at the bank of the Danube in Budapest, between Széchenyi rakpart and Akadémia utca. Its ma ...

. In his retirement he spent much of his time in

and

Austin Austin is the capital city of the U.S. state of Texas, as well as the seat and largest city of Travis County, with portions extending into Hays and Williamson counties. Incorporated on December 27, 1839, it is the 11th-most-populous city ...

Attainment

Bélády is known for the "Belady Algorithm", the OPT (or MIN)

Page Replacement Algorithm In a computer operating system that uses paging for virtual memory management, page replacement algorithms decide which memory pages to page out, sometimes called swap out, or write to disk, when a page of memory needs to be allocated. Page repl ...

. He co-designed and built

IBM M44/44X The IBM M44/44X was an experimental computer system from the mid-1960s, designed and operated at IBM's Thomas J. Watson Research Center at Yorktown Heights, New York. It was based on an IBM 7044 (the 'M44'), and simulated multiple 7044 virtual mach ...

, an experimental machine which is the first computer with multiple virtual machine organization. He is co-founder of an industrial research consortium, the MCC. Bélády also participated in the design of the earliest commercial

time-sharing In computing, time-sharing is the sharing of a computing resource among many users at the same time by means of multiprogramming and multi-tasking.DEC Timesharing (1965), by Peter Clark, The DEC Professional, Volume 1, Number 1 Its emergence a ...

systems, the TSS-67.

Awards

* 1969 & 1973: IBM Outstanding Contribution Awards * 1988: IEEE "for contributions to the design of large software systems" * 1990: J. D. Warnier Prize for Excellence in Information

Publications

* Belady, Laszlo A., "A Study of Replacement Algorithms for a Virtual Storage Computer," IBM Systems Journal, Vol. 5, No. 2 June 1966, pp. 78–10. * Belady, Laszlo A., and Meir L. Lehman, Program Evolution, Processes of Software Change,

Academic Press Academic Press (AP) is an academic book publisher founded in 1941. It was acquired by Harcourt, Brace & World in 1969. Reed Elsevier bought Harcourt in 2000, and Academic Press is now an imprint of Elsevier. Academic Press publishes reference ...

London London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...

, 1985.

References

{{DEFAULTSORT:Belady, Laszlo 1928 births 2021 deaths Hungarian computer scientists Computer systems researchers American software engineers Businesspeople in software Hungarian chief executives IBM employees Mitsubishi Electric people University of Colorado Boulder faculty Budapest University of Technology and Economics alumni Hungarian emigrants to the United States Hungarian expatriates in Germany Hungarian expatriates in France Scientists from Budapest