How do computers keep time?

My first laptop lost track of time, so that got me thinking: how do computers keep track of time? Can they do it forever? And why don't they lose track of time when we turn them off?

Turns out the answer is a combination of processor, quartz crystal and the internet. They all work together to keep time.

Sources

This video wouldn't be possible without the work of others. Here are the sources I've used during my research & script writing:

Schmidt, B. (2015, December). CPU Clocks and Clock Interrupts, and Their Effects on Schedulers. Accu. Retrieved from https://accu.org/index.php/journals/2185

Infographics: Operation Costs in CPU Clock Cycles. (2016, September 12). Retrieved from http://ithare.com/infographics-operation-costs-in-cpu-clock-cycles/

Jackson, J. (2015, March 2). Why computers still struggle to tell the time. PCWorld. Retrieved from https://www.pcworld.com/article/2891892/why-computers-still-struggle-to-tell-the-time.html

Year 2000 problem. Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Year_2000_problem

Year 2038 problem. Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Year_2038_problem

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APPLE II PLUS IIE THUNDERCLOCK PLUS CLOCK CARD. WorthPoint. Retrieved from https://www.worthpoint.com/worthopedia/apple-ii-plus-iie-thunderclock-plus-1792393546

Apple II system clocks. Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Apple_II_system_clocks

Clock Interrupt. (2009, November 1). Microsoft. Retrieved from https://social.microsoft.com/Forums/en-US/11ae5810-cb78-42a3-9761-efa3e8455993/clock-interrupt?forum=kernel

Clock Speed. (2017, May 22). TechTerms. Retrieved from https://techterms.com/definition/clockspeed

How do computers keep track of time? (2016, March 25). StackExchange. Retrieved from https://cs.stackexchange.com/questions/54933/how-do-computers-keep-track-of-time

Hertz. Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Hertz

Woodford, C. (2018, April 29). Quartz clocks and watches. Explain that stuff. Retrieved from https://www.explainthatstuff.com/quartzclockwatch.html

Network Time Protocol. Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Network_Time_Protocol

Nonvolatile BIOS memory. Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Nonvolatile_BIOS_memory

Quartz clock. Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Quartz_clock

Real-time clock. Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Real-time_clock

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