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László Bélády

László Bélády is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand László Bélády rather than just read about it. In short: László "Les" Bélády (April 29, 1928, in Budapest – November 6, 2021) was a Hungarian computer scientist notable for devising the Bélády's Min theoretical memory caching algorithm in 1966 while working at IBM Research. He also demonstrated the existence of a Bélády's anomaly.

Key takeaways

  • László Bélády belongs to computer science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect László Bélády to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of László Bélády from memory before moving on to harder problems.

Reference excerpt

László "Les" Bélády (April 29, 1928, in Budapest – November 6, 2021) was a Hungarian computer scientist notable for devising the Bélády's Min theoretical memory caching algorithm in 1966 while working at IBM Research. He also demonstrated the existence of a Bélády's anomaly. During the 1980s, he was the editor-in-chief of the IEEE Transactions on Software Engineering.

Education Bélády earned B.S. in Mechanical Engineering, then an M.S. in Aeronautical Engineering at the Technical University of Budapest in 1950.

Life and career He left Hungary after the Hungarian Revolution of 1956. Then he worked as a draftsman at Ford Motor Company in Cologne and as an aerodynamics engineer at Dassault in Paris. In 1961, he immigrated to the United States. In the 1960s and 1970s, he primarily lived in New York City with stints in California and England, 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. From 1961–1981, he worked at IBM Corp. at the Thomas J. Watson Research Center, where he worked as program manager for software technology. In his later years at IBM, he was responsible for software engineering worldwide until leaving for Tokyo to create its software research lab. In 1981, he worked as manager of software engineering at Japan Science Institute for two years. In 1984, he joined the Microelectronics and Computer Technology Corporation 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, 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 and foreign member of the Hungarian Academy of Sciences. In his retirement he spent much of his time in Budapest and Austin.

Attainment Bélády is known for the "Belady Algorithm", the OPT (or MIN) Page Replacement Algorithm. He co-designed and built IBM M44/44X, 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 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, London, 1985.

References

Worked examples

Example 1 — a first encounter with László Bélády

Start with the simplest possible case. Write down what László Bélády claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to László Bélády before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about László Bélády ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of László Bélády

In research
László Bélády appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses László Bélády in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
László Bélády is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1928 births, 2021 deaths, American software engineers, so understanding it makes those chapters shorter.
In everyday life
Look for László Bélády outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study László Bélády in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what László Bélády means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain László Bélády out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is László Bélády in simple terms?

László "Les" Bélády (April 29, 1928, in Budapest – November 6, 2021) was a Hungarian computer scientist notable for devising the Bélády's Min theoretical memory caching algorithm in 1966 while working at IBM Research. He also demonstrated the existence of a Bélády's anomaly.

Why does László Bélády matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study László Bélády?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on László Bélády.

Tags

  • 1928 births
  • 2021 deaths
  • American software engineers
  • Budapest University of Technology and Economics alumni
  • Businesspeople in the software industry
  • Computer systems researchers
  • Hungarian chief executives
  • Hungarian computer scientists
  • Hungarian emigrants to the United States
  • Hungarian expatriates in France
  • Hungarian expatriates in Germany
  • IBM employees

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