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These computer science trivia questions cover the field from Leibniz's binary arithmetic to the P versus NP problem, in 50 questions with answers: bits, bytes and nibbles, Boole and Shannon, Ada Lovelace's Note G, Turing's machine and his test, ENIAC's 18,000 tubes, Grace Hopper's compiler and her moth, the transistor and Moore's law, the first ARPANET message, the @ sign, the Web going royalty-free, Linux, Python, Java, quicksort, RSA and Deep Blue. The early questions suit anyone who has taken an intro course or read a little history; the later ones get into complexity theory, cryptography and who really invented what first. It works as a warm-up for a CS class, a hackathon icebreaker or a tech-company trivia night. Every answer has been checked against a documented source and each question shows its citation and a short explanation after you answer.
30 of 50 questions with answers and explanations. Play the quiz
Q 01A binary number uses only which two symbols?
0 and 1
Each digit is a bit, and eight of them make a byte that can hold any value from 0 to 255.
Q 02Which mathematician formalised the modern binary system in his 1703 Explication de l'Arithmétique Binaire?
Gottfried Leibniz
A Jesuit correspondent showed him the Chinese I Ching had arrived at binary notation independently, centuries earlier.
Q 03Who coined the word 'byte' in 1956 while designing IBM's Stretch computer?
Werner Buchholz
He deliberately spelled it with a y so it could not be mistyped into 'bit'; a half-byte is a nibble.
Q 04Why is 'byte' spelled with a y rather than as 'bite'?
To avoid accidental mutation into 'bit'
Eight bits became the standard byte with the IBM System/360 in the 1960s.
Q 05George Boole introduced Boolean algebra, the basis of digital circuits, in which 1847 book?
The Mathematical Analysis of Logic
His 1854 Laws of Thought expanded it; the term 'Boolean algebra' was only coined by Henry Sheffer in 1913.
Q 06Whose 1937 master's thesis applied Boolean algebra to switching circuits?
Claude Shannon
He was 21, and the thesis has been called the most important master's thesis of the century.
Q 07Ada Lovelace's Note G of 1843, often called the first computer program, calculated what?
Bernoulli numbers
It was written for Babbage's Analytical Engine, which was never built; she was the daughter of the poet Lord Byron.
Q 08What is the significance of 1815 in the Ada programming language's standard number MIL-STD-1815?
Ada Lovelace's birth year
She died in 1852 at 36, having described her approach to mathematics as 'poetical science'.
Q 09What kind of device did Turing's 1936 paper 'On Computable Numbers' introduce?
An abstract machine
It was 36 pages long and gave a precise definition of what it means for something to be computable.
Q 10At Bletchley Park, Turing designed an electromechanical machine to break Enigma. What was it called?
The bombe
The name came from the Polish bomba kryptologiczna, an earlier machine his design improved on.
Q 11Alan Turing's portrait appeared on which Bank of England banknote from June 2021?
£50
It was released on his birthday, eight years after Queen Elizabeth II granted him a posthumous pardon.
Q 12ENIAC, completed in 1945, is usually called the first what?
Programmable electronic computer
It weighed 30 tons and had 18,000 vacuum tubes; six women wrote its programs by wiring plugboards.
Q 13ENIAC was originally built to calculate what for the US Army?
Artillery firing tables
It was finished at the University of Pennsylvania just after the war it was built for had ended.
Q 21Which company did Gordon Moore, of Moore's law, co-found?
Intel
He and Robert Noyce left Fairchild to start it in 1968; Moore himself said the exponential 'can't continue forever'.
Q 22Which characters got through in the first ARPANET message of 29 October 1969 before the crash?
LO
The intended word was LOGIN; the full message went through about an hour later.
Q 23On 1 January 1983, 'flag day', the ARPANET switched to which protocol suite that still runs the internet?
TCP/IP
It replaced the Network Control Protocol; the ARPANET itself was decommissioned in 1990.
Q 14Roughly how many vacuum tubes did ENIAC contain by the end of its life in 1956?
18,000
Plus 7,200 diodes, 6,000 relays and 70,000 resistors, all in a machine 100 feet long.
Q 15Grace Hopper popularised which term after her team found a moth in a relay of the Harvard Mark II in 1947?
Debugging
The moth is taped into the logbook; 'bug' for a fault was already engineering slang in Edison's day.
Q 16Grace Hopper's FLOW-MATIC language was the main ancestor of which business language that is still in use?
COBOL
She held the rank of rear admiral, was nicknamed Grandma COBOL, and has a guided-missile destroyer named after her.
Q 17Grace Hopper finished her A-0 System in 1952. What kind of program was it, the first of its kind?
A compiler
She called it a compiler though it worked more like a linker; the idea that code could write code was radical.
Q 18Bardeen and Brattain first demonstrated the transistor in 1947 using which element?
Germanium
They shared the 1956 Nobel Prize in Physics with William Shockley; silicon took over later.
Q 19What is the most numerously manufactured artificial object in history?
The MOSFET transistor
More than 13 sextillion had been made by 2018; Atalla and Kahng demonstrated the first one at Bell Labs in 1960.
Q 20Moore's law says the number of transistors on a chip doubles roughly how often?
Every two years
Gordon Moore first said every year in 1965 and revised it to two in 1975; it is an observation, not a physical law.
Q 24Which symbol did Ray Tomlinson choose in 1971 to separate the email user from the host?
@
He picked it because it did not appear in usernames and already meant 'at'.
Q 25Tim Berners-Lee invented the World Wide Web while working at which institution?
CERN
He wrote the first browser, called WorldWideWeb, by the end of 1990, and CERN made the code royalty-free in April 1993.
Q 26On what date did CERN make the Web's protocol and code available royalty-free to the world?
30 April 1993
The decision is widely credited with letting the Web beat rival systems like Gopher.
Q 27The Linux kernel was first released on 17 September 1991 by which Finnish student?
Linus Torvalds
Its penguin mascot Tux was drawn by Larry Ewing, and it now runs all of the world's 500 fastest supercomputers.
Q 28As of 2017, how many of the world's 500 fastest supercomputers ran Linux?
All 500
Android, the dominant smartphone system, is also built on the Linux kernel.
Q 29The programming language created by Guido van Rossum in 1991 is named after what?
Monty Python's Flying Circus
Guido van Rossum released version 0.9.0 in 1991 and was the community's 'benevolent dictator for life' until 2018.
Q 30Unlike most languages, Python marks blocks of code using what?
Indentation
Get the whitespace wrong and the program simply will not run.