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50 free Operating Systems trivia questions with answers — science & nature quiz, new questions added Aug 2026.
An operating system is the software you never chose and cannot avoid: it decides what happens when you press the power button, how two apps share one processor, and why a crash looks the way it does. Its history is full of odd detail — a pun that named Unix, a chocolate bar that named a phone release, a big cat that named a Mac, and a Bell Labs project whose title came from a terrible 1950s film. These 50 questions cover the lineage of Windows and MS-DOS, the Mac from its first OS X release to the year-numbered versions of 2025, the Linux distributions and the Unix ideas beneath Android, iOS and ChromeOS, and the plain-English concepts a first-year computing course teaches: multitasking, memory tricks, file systems, shells and the crash that is not a blue screen. Every answer comes with a one-line explanation that adds something beyond the question. Play it to find out whether you know the machine you use all day, hand it to a computing class as a revision round, or print it for a pub quiz with a technical table.
30 of 50 questions with answers and explanations. Play the quiz
Q 01The 'DOS' in MS-DOS, the command-line software Microsoft first shipped for PCs in 1981, was short for what?
Disk Operating System
Disk Operating System was a generic phrase, and the very same code also shipped on the original PC under the badge PC DOS, with rival clones borrowing the name too.
Q 02MS-DOS reserved the drive letters A: and B: for which hardware, leaving C: for the first hard disk?
Floppy drives
Floppy drives came first because early PCs often had two of them and no hard disk at all, and Windows has honoured the leftover C: ever since.
Q 03Android 4.4 was co-branded with which chocolate bar under a promotional deal struck with Nestlé?
KitKat
KitKat was agreed in a phone call to Nestlé and sealed at Mobile World Congress in February 2013, and in the US the bar is actually made by Hershey under licence.
Q 04Which big cat codenamed Mac OS X 10.0, the 2001 release that began Apple's run of feline version names?
Cheetah
Cheetah was followed six months later by version 10.1, which Apple released on 25 September 2001 as a free update for everyone who had bought 10.0.
Q 05Android Inc., bought by Google in 2005, originally set out to build an OS for which devices?
Digital cameras
Digital cameras were the plan until investors balked, and in April 2004 the team pivoted to phones as a rival to Symbian and Windows Mobile.
Q 06Windows 10 was offered as a free upgrade for its first year to owners of which earlier versions?
7, 8 and 8.1
7, 8 and 8.1 owners got twelve months to upgrade free, part of Microsoft's aim of a billion devices on Windows 10 within three years, a mark it reached only in March 2020.
Q 07Which Apple utility, shipped with Mac OS X Leopard, restarts an Intel Mac into a full copy of Windows?
Boot Camp
Boot Camp only ever made sense on Intel chips, and Apple dropped it entirely for Apple silicon Macs, which can run ARM Windows only inside a virtual machine.
Q 08Which Mac OS X Leopard backup feature lets users scroll back through hourly snapshots of their files?
Time Machine
Time Machine keeps hourly backups for the past day, daily ones for the past month and weekly ones beyond that, until the backup disk runs out of space.
Q 09In 2020 Chromebooks outsold which rival machines for the first time, by taking share from Windows laptops?
Apple's Macs
Apple's Macs were overtaken during the remote-schooling boom of 2020, when cheap Chromebooks swallowed sales that would otherwise have gone to Windows laptops.
Q 10In 2025 Apple jumped straight from iOS 18 to which version number, a year-based label shared by every Apple OS?
26
26 is a year-based label: the software serves the year after its autumn release, and Apple applied the same convention to every one of its platforms at once.
Q 11Windows 11's 2021 requirements excluded millions of capable PCs by demanding version 2.0 of which security chip?
Trusted Platform Module
Trusted Platform Module 2.0 keeps encryption keys in hardware, and Microsoft called it a 'critical building block' against firmware and hardware attacks.
Q 12Which two makers shipped the first Chromebooks in June 2011, weeks after Google unveiled them at its I/O conference?
Samsung and Acer
Samsung and Acer got there first because Google's own Cr-48 test laptop of 2010 was only ever given away to pilot users and never sold.
Q 13Microsoft's 2016 Anniversary Update let PC users run a real bash shell natively via which new compatibility layer?
Q 21Microsoft's own 1991 video said the initials of Windows NT, its 32-bit line launched in 1993, stood for what?
New Technology
New Technology was the gloss in a 1991 Bill Gates video, but by 1998 Gates was saying the letters no longer carried any specific meaning at all.
Q 22Which real-time operating system from Wind River ran NASA's Curiosity rover and the Mars Reconnaissance Orbiter?
VxWorks
VxWorks also flew on the 1994 Clementine lunar probe and the earlier Mars rovers Spirit and Opportunity, a résumé few operating systems can match.
Q 23Unix began as 'Unics', a pun on which sprawling time-sharing project that Bell Labs had just walked away from?
Multics
Windows Subsystem for Linux
Windows Subsystem for Linux at first implemented Linux system calls inside the Windows kernel; WSL 2, announced in 2019, switched to running a real Linux kernel in a lightweight virtual machine.
Q 14Which Linux distribution, bankrolled by Mark Shuttleworth, is named from a Nguni word for 'humanity to others'?
Ubuntu
Ubuntu has shipped a new version every six months since its first release in October 2004, each one named after an animal with an alliterative adjective.
Q 15Which company agreed in October 2018 to buy Red Hat, the enterprise Linux firm, for about $34 billion?
IBM
IBM closed the deal in July 2019 and kept Red Hat as an independent subsidiary, which stayed among the largest corporate contributors to the Linux kernel.
Q 16FAT32, the file system commonly used on USB sticks, cannot hold a single file larger than what size?
4 GB
4 GB minus one byte is the ceiling, which is why one large video file refuses to copy onto a FAT32 stick until it is reformatted as exFAT, FAT's successor.
Q 17Which multitasking scheme of classic Mac OS and 16-bit Windows relies on each program voluntarily yielding the CPU?
Cooperative
Cooperative multitasking let one hung program freeze the whole machine, which is why Windows 95 and Mac OS X both moved to preemptive scheduling that forcibly shares time.
Q 18Edsger Dijkstra's dining philosophers puzzle, five thinkers sharing five forks, illustrates which multitasking hazard?
Deadlock
Deadlock strikes when every philosopher grabs the fork on the left and waits forever for the right one, and operating systems face the same trap with locks on files and memory.
Q 19Which technique, pioneered on Manchester's Atlas computer, lets programs address more RAM than is physically installed?
Virtual memory
Virtual memory parks idle pages on disk and pulls them back on demand, and when a machine spends all its time doing that the condition is called thrashing.
Q 20What do Linux and macOS call the fatal crash that Windows users know as the blue screen of death?
Kernel panic
Kernel panic is the Unix-family term, and Mac OS X 10.2 to 10.7 announced one with a multilingual message telling the user to restart the computer.
Multics was a joint venture of Bell Labs, General Electric and a university partner, and the Bell researchers who quit it built Unix as a pared-down replacement.
Q 24Ken Thompson's wish to keep playing which game of his own on a spare Bell Labs minicomputer helped spark Unix in 1969?
Space Travel
Space Travel simulated a flight through the solar system, and rewriting it for a cast-off PDP-7 is how Thompson came to write the first pieces of Unix.
Q 25In 1992 Andrew Tanenbaum declared 'Linux is obsolete' on Usenet because Torvalds had spurned which design for its core?
Microkernel
Microkernel designs push drivers and file systems out of the privileged core, as Tanenbaum's own teaching system did, yet the monolithic Linux went on to win the world.
Q 26Bell Labs' research successor to Unix took the name 'Plan 9' from a 1957 film by which notoriously inept director?
Ed Wood
Ed Wood's Plan 9 from Outer Space supplied the title, and the system's lasting gift was UTF-8, which Ken Thompson invented as its native text encoding.
Q 27Bash, the default command shell on most Linux systems, is a pun on the surname of which earlier shell's author?
Stephen Bourne
Stephen Bourne wrote the original sh for Version 7 Unix in 1979, and Brian Fox's 1989 'Bourne Again SHell' was the GNU project's free replacement for it.
Q 28The Unix command 'sudo', which runs a single command with administrator rights, was originally short for what?
Superuser do
Superuser do lets an ordinary account borrow root's powers for one command, which is why Linux how-to guides are littered with it.
Q 29In preemptive multitasking, what is the term for the few milliseconds a process gets before the scheduler moves on?
Time slice
Time slice, also called a quantum, is what a frozen program can no longer hog: when it expires the core forcibly hands the processor to the next process in line.
Q 30In which CPU mode do ordinary apps run, with the hardware itself refusing any privileged instruction they attempt?
User
User mode is the fenced-off side of the divide; the core of the OS runs with unrestricted power, and every system call is a controlled crossing between the two.