Computer Science Trivia
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These computer science trivia questions cover the field from Leibniz's binary arithmetic to the P versus NP problem, in 99 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 99 questions with answers and explanations. Play the quiz
Q 01A binary number uses only which two symbols?
0 and 1
Binary needs only 0 and 1 because a circuit just has to tell two states apart, such as a switch being off or on, which also resists electrical noise.
Q 02Which mathematician formalised the modern binary system in his 1703 Explication de l'Arithmétique Binaire?
Gottfried Leibniz
Gottfried Leibniz's paper also discussed China: the Jesuit Joachim Bouvet had sent him I Ching hexagrams, which Leibniz read as binary numbers.
Q 03Which IBM computer beat Jeopardy! champions Ken Jennings and Brad Rutter in 2011?
Watson
Watson was named after IBM's first CEO, Thomas J. Watson, and it played the matches without being connected to the internet.
Q 04Why is 'byte' spelled with a y rather than as 'bite'?
To avoid accidental mutation into 'bit'
Werner Buchholz respelled 'bite' in 1956 to avoid accidental mutation into 'bit'; early Stretch bytes held one to six bits, and IBM's System/360 later made eight standard.
Q 05George Boole introduced Boolean algebra, the basis of digital circuits, in which 1847 book?
The Mathematical Analysis of Logic
The Mathematical Analysis of Logic was sparked by a public quarrel between De Morgan and Sir William Hamilton, and Boole expanded it into The Laws of Thought in 1854.
Q 06Whose 1937 master's thesis applied Boolean algebra to switching circuits?
Claude Shannon
Claude Shannon wrote it as an MIT student, and psychologist Howard Gardner called it possibly the most important, and most famous, master's thesis of the century.
Q 07Ada Lovelace's Note G of 1843, often called the first computer program, calculated what?
Bernoulli numbers
The Bernoulli numbers program was written for Babbage's Analytical Engine, which was never built, so it was not tested in Lovelace's lifetime.
Q 08What is the significance of 1815 in MIL-STD-1815, the US military's programming language standard?
Ada Lovelace's birth year
Ada Lovelace's birth year numbers the standard for Ada, the language named after her, and its manual was approved on 10 December 1980, her birthday.
Q 09What kind of device did Turing's 1936 paper 'On Computable Numbers' introduce?
An abstract machine
An abstract machine, later called the Turing machine, reads and writes symbols on an endless tape, and Turing used it to prove some problems no machine can ever solve.
Q 10Which electromechanical machine did Alan Turing design at Bletchley Park to help break Enigma?
The bombe
The bombe took its name from the Polish bomba, an earlier device, while Colossus and its predecessor Heath Robinson attacked a different German cipher, Lorenz.
Q 11Alan Turing's portrait appeared on which Bank of England banknote from June 2021?
£50
The £50 note came out on 23 June 2021, Turing's birthday, less than eight years after Queen Elizabeth II's posthumous royal pardon.
Q 12ENIAC, completed in 1945, is usually called the first what?
Programmable electronic computer
Programmable electronic computer is ENIAC's usual title, but Britain's secret Colossus was already running in 1944, so ENIAC is often called the first general-purpose one.
Q 13ENIAC was originally built to calculate what for the US Army?
Artillery firing tables
Q 21Which company did Gordon Moore, of Moore's law, co-found?
Intel
Intel was founded in 1968 by Moore and Robert Noyce, who had left Fairchild Semiconductor, the startup they had helped found as two of the 'traitorous eight'.
Q 22Which characters got through in the first ARPANET message of 29 October 1969 before the crash?
LO
LO got through because the system crashed after the first two letters of LOGIN, and the full login worked 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
TCP/IP replaced the older NCP on flag day, when the new protocols were permanently switched on, and the ARPANET itself was decommissioned in 1990.
Artillery firing tables were being worked out by hand, and ENIAC could compute a shell's trajectory in seconds instead of hours.
Q 14Roughly how many vacuum tubes did ENIAC contain by the end of its life in 1956?
18,000
ENIAC's 18,000 vacuum tubes let it run at electronic speed, with no mechanical parts slowing its calculations.
Q 15Grace Hopper popularised which term after her team found a moth in a relay of the Harvard Mark II in 1947?
Debugging
Debugging and 'bug' already existed as engineering slang, which is why the operators' log joked that the moth was the first actual case of a bug being found.
Q 16Grace Hopper's FLOW-MATIC language was the main ancestor of which business language that is still in use?
COBOL
COBOL inherited FLOW-MATIC's English word commands, which Hopper introduced because business customers refused to learn symbols.
Q 17What kind of program was Grace Hopper's 1952 A-0 System, often called the first of its kind?
A compiler
A compiler was the name for A-0 then, though it worked more like a linker, and Hopper said nobody would touch it because computers 'could only do arithmetic'.
Q 18Which element did Bardeen and Brattain use to build the first working transistor at Bell Labs in 1947?
Germanium
Germanium carried the first point-contact transistor in December 1947, and Bardeen, Brattain and Shockley shared the 1956 Nobel Prize in Physics for it.
Q 19What is the most numerously manufactured artificial object in history?
The MOSFET transistor
The MOSFET transistor passed an estimated 13 sextillion units by 2018, since a single memory chip or microprocessor can hold billions of them.
Q 20Moore's law says the number of transistors on a chip doubles roughly how often?
Every two years
Every two years was Gordon Moore's 1975 revision of his 1965 forecast of every year, and the 'law' is an observed trend, not a law of physics.
Q 24Which symbol did Ray Tomlinson choose in 1971 to separate the email user from the host?
At sign
The at sign was chosen because usernames never used it and it already read as 'at', so an address says user at host, the format email still uses.
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 26Tim Berners-Lee ran the first web server on a NeXT computer, from the company founded by whom?
Steve Jobs
Steve Jobs founded NeXT in 1985 after leaving Apple, and Apple's 1997 purchase of NeXT brought him back to the company.
Q 27Which university student released a Unix-like kernel on 17 September 1991?
Linus Torvalds
Linus Torvalds wanted to call it Freax, but his friend who ran the FTP server hosting it named the folder Linux, and the name stuck.
Q 28Which smartphone operating system is built on a modified version of the Linux kernel?
Android
Android began as an operating system for digital cameras, and its startup switched to phones in 2004, a year before Google bought it.
Q 29Which Apple computer was introduced by the famous '1984' Super Bowl commercial?
Macintosh
Macintosh's launch ad was directed by Ridley Scott and showed an athlete hurling a hammer into Big Brother's screen as a blow against conformity.
Q 30Unlike most languages, Python marks blocks of code using what?
Indentation
Indentation is part of Python's syntax, and the language itself is named after Monty Python's Flying Circus, not the snake.