What Time is It?
Image by Rich Bowen on Flickr
Learn about the origin of Unix time, the calendar system used by digital devices.
You know the day and time when your classes begin but have you thought about what time is? Why 24 hours, for example, or 7 days in a week not 5? Who decided?
Keeping time is a technology and, like many technologies, it’s created by humans to solve problems. Mostly time is used to keep people synchronized. We might agree to have breakfast when the sun rises but what about lunch? What about classes or sports?
Computers have a similar problem. Not only do they have to share data — and a standard way to describe data, but computers also need to manage time to perform tasks and to work with other computers.
Computers use Unix time. The start time is January 1, 1970 at 00:00:00 minus any leap seconds since then. From that moment, computers count forward in units of time that generate a long integer or number which can be translated into dates humans recognize. For example, this issue is released on February 1, 2018 which in Unix time is 1517443200. That’s easy to remember, isn’t it? Computers would tell you 1517443200 is easier to remember.
Why 1970? Because the Unix operating system was under development around 1969 to the early 1970s and January 1, 1970 at midnight was an easy reference point.
Of course, it’s not that easy. There are old 32-bit computers which will run out digits to count Unix time at 2147483647 or what we call January 19, 2038 at 3:14:08 in the morning. Be sure to put that in your calendar if you happen to have an old computer. The other kind of computer, a modern 64-bit computer, will run out of digits on Sunday, December 4, 292277026596, or almost 22 times the estimated current age of the universe.
There are calculators online to help convert our dates into Unix time. And using a command line interface on some computers, typing date +%s displays the current day and time in Unix time.
What other systems have humans created to track and measure time? We currently use the Gregorian calendar which improved on the Julian calendar from the Roman empire. But there’s Jewish, Chinese, Muslim, Egyptian, and other cultures also have created their own calendars.
Learn More
Unix Time
https://en.wikipedia.org/wiki/Unix_time
Epoch Converter
https://www.epochconverter.com/
Why Does Unix Time Start at 1970/01/01?
https://www.quora.com/Why-does-Unix-time-start-at-1970-01-01
French Republican Calendar
https://en.wikipedia.org/wiki/French_Republican_Calendar
Author
Also In The February 2018 Issue
In an era before telephones, a clever code was created to send messages by telegraph.
A simple coding activity that creates a virtual tic-tac-toe board with pieces.
Seven days to design, code, and debug a program with PyGame. What could go wrong?
Play with your friends or connect to Minecraft servers all around the world.
Turning scientific data into music can lead to new insights and new solutions.
Tools to help you design and print your own jewelry. Who says geeks can’t be fashionable?
Say hello to your new favorite robot: spherical, programmable, and durable. It can even swim!
Introduction to a dynamic, Python-like language that can do scientific calculations at high speed.
The perfect language to help you transition into a new way of coding.
Create a new and improved variation of the classic 1960s board game with micro:bit.
Learn about the origin of Unix time, the calendar system used by digital devices.
Help students apply their computational thinking skills outside the classroom.
Could a human brain be simulated by a computer? Would it think and feel like we do?
Links from the bottom of all the February 2018 articles, collected in one place for you to print, share, or bookmark.
Interesting stories about computer science, software programming, and technology for February 2018.
