computer science

J. W. J. Williams

J. W. J. Williams 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 J. W. J. Williams rather than just read about it. In short: John William Joseph (Bill) Williams (September 1930 – 29 September 2012) was a computer scientist best known for inventing heapsort and the binary heap data structure in 1963 while working for Elliot Bros. (London) Ltd.

Key takeaways

J. W. J. Williams 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 J. W. J. Williams to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of J. W. J. Williams from memory before moving on to harder problems.

Reference excerpt

John William Joseph (Bill) Williams (September 1930 – 29 September 2012) was a computer scientist best known for inventing heapsort and the binary heap data structure in 1963 while working for Elliot Bros. (London) Ltd.

Personal life He was born in England, in the district of Chippenham in Wiltshire County, to William Henry Williams and his wife (née Haines). On 3 March 1962 he married age 31) married Ann Zerny (a nurse, age 23) at Christ Church in Chorleywood Parish in Hertfordshire County. They had three children. In 1974, he moved to Ottawa, Ontario, Canada. He died on 29 September 2012 at age 82.

Career In 1952, he received a B.Sc. in mathematics from King's College, University of London. In England, he worked as a programmer for Elliot Automation, formerly Elliot Brothers (London) Limited, where he invented heapsort and used it to create the event-driven Elliott Simulator Package (ESP) with the help of C. A. R. (Tony) Hoare. He also worked for English Electric and GEC. He worked with Donald E. Knuth to develop a two-heap data structure that they called a "priority deque", published as an exercise in The Art of Computer Programming in 1973. After moving to Canada in 1974, he worked for Bell-Northern Research Ltd., Ottawa (BNR) and Northern Telecom (Nortel) until retiring in 1995. At BNR, he worked on various software and hardware systems such as the DMS-100 digital telephone switch, publishing a paper about their software in June 1982.

References

Worked examples

Example 1 — a first encounter with J. W. J. Williams

Start with the simplest possible case. Write down what J. W. J. Williams 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 J. W. J. Williams 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 J. W. J. Williams 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 J. W. J. Williams

In research: J. W. J. Williams 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 J. W. J. Williams 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: J. W. J. Williams is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1930 births, 2012 deaths, 20th-century Canadian inventors, so understanding it makes those chapters shorter.
In everyday life: Look for J. W. J. Williams 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 J. W. J. Williams in 20 minutes

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

Frequently asked questions

What is J. W. J. Williams in simple terms?

Why does J. W. J. Williams 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 J. W. J. Williams?

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 J. W. J. Williams.